2.1 Chiller Rules
2.1.3.1 - Chilled Water Leaving Temperature Greater Than Setpoint
Summary
The chilled water leaving temperature is greater than the leaving water temperature setpoint, indicating bad control, energy waste, and potential comfort complaints.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chilled Water Leaving Temperature |
ChWLTemp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chilled Water Setpoint |
ChWSp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
60 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| Temperature Threshold |
Numeric |
2 |
This number (in Fahrenheit) is the temperature threshold. The chilled water leaving temperature must exceed the sum of the temperature threshold added to the chilled water setpoint for a period longer than the delay in order for a fault condition to exist. |
2.1.4.1 - Chilled Water Leaving Temperature Less Than Setpoint
Summary
The chiller water leaving temperature is less than the leaving water temperature setpoint, indicating bad control and energy waste.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chilled Water Leaving Temperature |
ChWLTemp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chilled Water Setpoint |
ChWSp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
60 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| Temperature Threshold |
Numeric |
2 |
This number (in Fahrenheit) is the temperature threshold. The chilled water leaving temperature must not exceed the difference between the temperature threshold subtracted from the chilled water setpoint for a period longer than the delay in order for a fault condition to exist. |
2.1.5.1 - Chiller Low Temperature Differential (Low Delta T)
Summary
The chiller temperature differential (Delta T) is much lower than design.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chiller Water Entering Temperature |
ChWETemp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chilled Water Leaving Temperature |
ChWLTemp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
120 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| Minimum Temperature Differential |
Numeric |
5 |
This number (in Fahrenheit) is the minimum temperature differential. The difference value of the chilled water leaving temperature subtracted from the chilled water entering temperature must not exceed the minimum temperature differential for a period longer than the delay in order for a fault condition to exist. |
2.1.6.1 – Chilled Water Leaving Temperature Sensor Failure
Summary
The chilled water leaving temperature sensor has failed. The temperature sensor point is invariant or is outside the expected range.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chilled Water Leaving Temperature |
ChWLTemp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
120 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| High Threshold |
Numeric |
70 |
This number (in Fahrenheit) is the maximum allowed value of the chilled water leaving temperature. The chilled water leaving temperature must exceed the high threshold for a period longer than the delay in order for a fault condition to exist. |
| Low Threshold |
Numeric |
20 |
This number (in Fahrenheit) is the minimum allowed value of the chilled water leaving temperature. The chilled water leaving temperature must not exceed the low threshold for a period longer than the delay in order for a fault condition to exist. |
| Variance Threshold |
Numeric |
0.01 |
This number (in Fahrenheit) is the variance threshold. The difference value of the high threshold and low threshold must not exceed the variance threshold for a period longer than the delay in order for a fault condition to exist. |
2.1.6.2 - Chilled Water Entering Temperature Sensor Failure
Summary
The chilled water entering temperature sensor has failed. The temperature sensor point is invariant or is outside the expected range.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chilled Water Entering Temperature |
ChWETemp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
120 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| High Threshold |
Numeric |
70 |
This number (in Fahrenheit) is the maximum allowed value of the chilled water entering temperature. The chilled water entering temperature must exceed the high threshold for a period longer than the delay in order for a fault condition to exist. |
| Low Threshold |
Numeric |
20 |
This number (in Fahrenheit) is the minimum allowed value of the chilled water entering temperature. The chilled water entering temperature must not exceed the low threshold for a period longer than the delay in order for a fault condition to exist. |
| Variance Threshold |
Numeric |
0.01 |
This number (in Fahrenheit) is the variance threshold. The difference value of the high threshold and low threshold must not exceed the variance threshold for a period longer than the delay in order for a fault condition to exist. |
2.1.6.3 - Condenser Water Entering Temperature Sensor Failure
Summary
The condenser water entering temperature sensor has failed. The temperature sensor point is invariant or is outside the expected range.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Condenser Water Entering Temperature |
CWETemp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
120 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| High Threshold |
Numeric |
100 |
This number (in Fahrenheit) is the maximum allowed value of the condenser water entering temperature. The condenser water entering temperature must exceed this threshold for a period longer than the delay in order for a fault condition to exist. |
| Low Threshold |
Numeric |
35 |
This number (in Fahrenheit) is the minimum allowed value of the condenser water entering temperature. The condenser water entering temperature must not exceed this threshold for a period longer than the delay in order for a fault condition to exist. |
| Variance Threshold |
Numeric |
0.01 |
This number (in Fahrenheit) is the variance threshold. The difference value of the high threshold and low threshold must not exceed the variance threshold for a period longer than the delay in order for a fault condition to exist. |
Rule 2.1.6.4 - Condenser Water Leaving Temperature Sensor Failure
Summary
The condenser water leaving temperature sensor has failed. The temperature sensor point is invariant or is outside the expected range.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Condenser Water Leaving Temperature |
CWLTemp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
120 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| High Threshold |
Numeric |
100 |
This number (in Fahrenheit) is the maximum allowed value of the condenser water leaving temperature. The condenser water leaving temperature must exceed this threshold for a period longer than the delay in order for a fault condition to exist. |
| Low Threshold |
Numeric |
35 |
This number (in Fahrenheit) is the minimum allowed value of the condenser water leaving temperature. The condenser water leaving temperature must not exceed this threshold for a period longer than the delay in order for a fault condition to exist. |
| Variance Threshold |
Numeric |
0.01 |
This number (in Fahrenheit) is the variance threshold. The difference value of the high threshold and low threshold must not exceed the variance threshold for a period longer than the delay in order for a fault condition to exist. |
2.1.6.5 - Outside Air Temperature Sensor Failure
Summary
The outside air temperature sensor has failed. The temperature sensor point is invariant or is outside the expected range.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Outside Air Temperature |
OaTemp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
60 |
The delay represents a span of time in minutes during which the sensor must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| High Threshold |
Numeric |
130 |
This number (in Fahrenheit) is the maximum allowed value of the outside air temperature. The outside air temperature must exceed this threshold for a period longer than the delay in order for a fault condition to exist. |
| Low Threshold |
Numeric |
-40 |
This number (in Fahrenheit) is the minimum allowed value of the outside air temperature. The outside air temperature must not exceed this threshold for a period longer than the delay in order for a fault condition to exist. |
| Variance Threshold |
Numeric |
0.01 |
This number (in Fahrenheit) is the variance threshold. The difference value of the high threshold and low threshold must not exceed the variance threshold for a period longer than the delay in order for a fault condition to exist. |
2.1.7.1 - Chiller Status is Off When Commanded On
Summary
The chiller status indicates it is 'Off', but the chiller is being commanded 'On', indicating a problem, inefficient operation, and potential comfort complaints.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chiller Command |
ChrCmd |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
15 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
2.1.8.1 - Chiller Status is On When Commanded Off
Summary
The chiller status indicates it is 'On', but the chiller is being commanded 'Off', potentially wasting energy.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chiller Command |
ChrCmd |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
15 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
2.1.9.1 - Chilled Water Supply Temperature Setpoint is Less Than Low Limit
Summary
The chilled water supply temperature setpoint is less than the low limit, wasting energy. The setpoint may be overridden or set lower than design.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chilled Water Setpoint |
ChWSp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
15 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| Low Temperature Setpoint Limit |
Numeric |
42 |
This number (in Fahrenheit) is the minimum allowed value of the chiller supply water temperature. The chilled water setpoint must not exceed this threshold for a period longer than the delay in order for a fault condition to exist. |
2.1.10.1 - Chiller Chilled Water Flow Rate is Too High
Summary
Manufacturers have minimum chilled water flow rates through the evaporator. It is determined the flow rate for this chiller is below manufacturer's recommendations.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
(CHWFlow) || (ChWPressDiff & ChWPressDiffSp) || (EvFlowSw) |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chilled Water Pump Status |
ChWCPSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chilled Water Flow |
CHWFlow |
This point must be a direct child of the equipment that the rule is attached to. |
Optional |
Scalar |
| Evaporator Differential Pressure |
EvDifPrsSp |
This point must be a direct child of the equipment that the rule is attached to. |
Optional |
Scalar |
| Evaporator Differential Pressure Setpoint |
EvDifPrsSp |
This point must be a direct child of the equipment that the rule is attached to. |
Optional |
Scalar |
| Evaporator Flow Switch |
EvFlowSw |
This point must be a direct child of the equipment that the rule is attached to. |
Optional |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
60 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| MIN_CHW_FLOW |
Numeric |
100 |
The Minimum chilled water flow threshold. |
2.1.11.1 - Chiller Chilled Water Valve is Open When Chiller is Off
Summary
Isolation valves are required when more than one chiller is serving a chilled water system and should be closed when the chiller and associated chiller pump are off.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chilled Water Pump Status |
ChWCPSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chilled Water Isolation Valve |
ChWIsoVlvCmd |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
60 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
2.1.12.1 - Chiller Water Supply Temperature Setpoint Can Be Increased (Reset)
Summary
Most of the chilled water valve positions are less than a high valve limit, indicating an opportunity to increase the chilled water supply temperature setpoint. Chilled water supply temperature reset is required by ASHRAE Standard 90.1.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| VAV Cooling Command |
ClgCmd |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
60 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| Cooling Value Threshold |
Numeric |
90 |
This number is the cooling value threshold in percent. If most of the hot water valve positions (ClgCmd's) of the VAV/AHU/HX/FCU served by the chiller are less than the cooling valve threshold for a period longer than the delay in order for a fault condition to exist. |
| % of Cooling Equipment Valves Below Threshold |
Numeric |
90 |
This number is the % of cooling equipment valves below threshold. If most of the cooling water valve positions (ClgCmd's) of the VAV/AHU/HX/FCU served by the chiller are less than the cooling valve threshold for a period longer than the delay in order for a fault condition to exist. |
2.1.13.1 - Chiller Evaporator Saturated Refrigerant Temperature Too Low
Summary
The temperature at that a fluid will phase change from liquid to vapor is too low.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Evaporator Saturation Refrigeration Temperature |
EvSatRfgTmp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Evaporator Saturation Refrigeration Temperature Setpoint |
EvSatRfgTmpSp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
0 |
The delay represents a span of time in minutes during which the cooling tower must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| TEMP_ERR |
Numeric |
2 |
Temperature sensor error threshold. The evaporator saturation refrigeration temperature setpoint must be greater than the evaporator saturation refrigeration temperature plus this constant for a period longer than the delay for a fault to exist. |
2.1.14.1 - Chiller High Evaporator Pressure
Summary
The pressure at which the refrigerant is a phase changing from a liquid to a vapor and is too high.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Evaporator Refrigeration Pressure |
EvRfgPrs |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Evaporator Saturation Refrigeration Pressure Setpoint |
EvRfgPrsSp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
0 |
The delay represents a span of time in minutes during which the cooling tower must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| PRS_ERR |
Numeric |
5 |
Pressure sensor error threshold. |
2.1.15.1 - Chiller Low Evaporator Pressure
Summary
The pressure at which the refrigerant is a phase changing from a liquid to a vapor and is too high.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Evaporator Refrigeration Pressure |
EvRfgPrs |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Evaporator Refrigeration Pressure Setpoint |
EvRfgPrsSp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
0 |
The delay represents a span of time in minutes during which the cooling tower must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| PRS_ERR |
Numeric |
5 |
Pressure sensor error threshold. |
Rul 2.1.16.1 - Chiller Evaporator Approach Temperature is Too Large
Summary
The difference between the leaving chilled water temperature and the saturated refrigerant evaporating temperature exceeds the design approach temperature. By monitoring this and addressing the cause can extend the life of the chiller.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chilled Water Leaving Temperature |
ChWLTemp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Evaporator Saturation Refrigeration Temperature |
EvSatRfgTmp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
0 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| EV_APPROACH |
Numeric |
8 |
The evaporator approach threshold |
2.1.17.1 - Chiller Condenser Water Temperature Difference is Higher Than Normal
Summary
The condenser water temperature difference is higher than normal.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Condenser Water Circ Pump Status |
CWCPSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Condenser Water Entering Temperature |
CWETemp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Condenser Water Leaving Temperature |
CWLTemp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
0 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| Chilled Water Temperature Differential |
Numeric |
10 |
The condenser water temperature differential threshold. |
| Chilled Water Temperature Error |
Numeric |
2 |
The condenser water temperature error threshold. |
2.1.18.1 - Chiller Condenser Approach Temperature is Too Large
Summary
The difference between the condenser liquid refrigerant temperature and the leaving condenser water temperature exceeds the design approach temperature. By monitoring this and addressing the cause can extend the life of the chiller.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Condenser Water Leaving Temperature |
CWLTemp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Condenser Saturation Refrigeration Temperature |
CdSatRfgTmp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
0 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| Condenser Approach |
Numeric |
3 |
The condenser approach threshold. |
2.1.19.1 - Chiller Condenser Water Flow Rate is Too Low
Summary
Manufacturers have minimum condenser water flow rates through the condenser. It is determined the flow rate for this chiller is below manufacturer's recommendations.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
(CWFlow & CWFlowSp) || (CWFlow) || (CdDifPrs & CdDifPrsSp) || CdFlowSw |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Condenser Water Circ Pump Status |
CWCPSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Condenser Differential Pressure |
CdDifPrs |
This point must be a direct child of the equipment that the rule is attached to. |
Optional |
Scalar |
| Condenser Differential Pressure Setpoint |
CdDifPrsSp |
This point must be a direct child of the equipment that the rule is attached to. |
Optional |
Scalar |
| Condenser Flow Switch |
CdFlowSw |
This point must be a direct child of the equipment that the rule is attached to. |
Optional |
Scalar |
| Condenser Water Flow |
CWFlow |
This point must be a direct child of the equipment that the rule is attached to. |
Optional |
Scalar |
| Condenser Water Flow Setpoint |
CWFlowSp |
This point must be a direct child of the equipment that the rule is attached to. |
Optional |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
0 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| Min Condenser Water Flow |
Numeric |
100 |
The minimum condenser water flow threshold. |
2.1.20.1 - Chiller Could Be in a Surge Condition
Summary
Chiller Lift, which is the difference between condenser refrigerant pressure and evaporator refrigerant pressure. If this differential increases to where it exceeds the system's pumping capacity, refrigerant will flow backward through the compressor wheel every few seconds. Pressure builds up in the compressor, causing the refrigerant to surge forward again, and the cycle repeats.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Evaporator Saturation Refrigeration Pressure |
EvSatRfgPrs |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
0 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| Max Refrigerant Pressure |
Numeric |
110 |
The maximum refrigerant pressure differential threshold. |
2.1.21.1 - Chiller Condenser Water Isolation Valve is Open When Chiller is Off
Summary
Isolation valves are required when more than one chiller is served by a condenser water system and should be closed, when the chiller and associated chiller pump are off.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Condenser Water Circ Pump Status |
CWCPSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Condenser Water Isolation Valve |
CWIsoVlvCmd |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
0 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
2.1.22.1 - Compressor Discharge Refrigerant Temperature is Too High
Summary
The compressor discharge refrigerant temperature is too high.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Condenser Refrigeration Temperature |
CdRfgTmp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
0 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| Temperature Limit |
Numeric |
200 |
The temperature limit threshold. |
2.1.23.1 - Compressor Discharge Refrigerant Pressure is Too High
Summary
Compressor discharge refrigerant pressure is too high.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Condenser Refrigeration Pressure |
CdRfgPrs |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constant
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
0 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| Pressure Limit |
Numeric |
136.5 |
The pressure limit threshold. |
2.1.24.1 - Compressor Suction Refrigerant Pressure is Too Low
Summary
Compressor suction refrigerant pressure is too low.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Evaporator Refrigeration Pressure |
EvRfgPrs |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
0 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| Pressure Limit |
Numeric |
31.5 |
The pressure limit threshold. |
2.1.25.1 - Compressor Suction Refrigerant Pressure is Too High
Summary
Compressor suction refrigerant pressure is too high.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Evaporator Refrigeration Pressure |
EvRfgPrs |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
0 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| Pressure Limit |
Numeric |
38.5 |
The pressure limit threshold. |
2.1.26.1 - Chiller Lift is Greater Than the Rating of the Compressor
Summary
When the compressor suction pressure is low and the compressor discharge pressure is high, the chiller could be experiencing a surge situation.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Evaporator Refrigeration Pressure |
EvRfgPrs |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Condenser Refrigeration Pressure |
CdRfgPrs |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
0 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| Chiller Lift Threshold |
Numeric |
130 |
|
2.1.27.1 - Chiller Low Oil Pressure Differential
Summary
When the oil pressure differential is lower than its threshold value while the chiller is operational.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chiller Oil Pressure Differential |
ChrOilPrsDiff |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
30 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| Low Oil Differential Pressure Threshold |
Numeric |
10
|
The pressure limit threshold. |
2.1.28.1 - Chiller High Oil Pressure Differential
Summary
When the oil pressure differential is high than its threshold value while chiller is operational.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chiller Oil Pressure Differential |
ChrOilPrsDiff |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
30 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| High Oil Differential Pressure Limit Threshold |
Numeric |
25 |
The pressure limit threshold. |
2.1.29.1 - Chiller High Oil Temperature
Summary
When the oil sump temperature is greater than its threshold value when the chiller is operational.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chiller Oil Temp |
ChrOilTemp |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
30 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| Oil Sump Temperature Limit Threshold |
Numeric |
38.5 |
The pressure limit threshold. |
2.1.30.1 - Chiller Low Compressor Discharge Superheat
Summary
Discharge temperature minus the condenser refrigerant saturated temperature represents the discharge superheat differential temperature. The fault occurs when the compressor discharge superheat differential temperature is lower than its threshold value while chiller is operational.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Condenser Refrigeration Temperature |
CdRfgTmp |
This point must be a direct child of the equipment that the rule is attached to. |
Optional |
Scalar |
| Compressor Discharge Superheat Differential Temperature |
CmpDisSprHtDifTmp |
This point must be a direct child of the equipment that the rule is attached to. |
Optional |
Scalar |
| Compressor Discharge Temperature |
CmpDisTmp |
This point must be a direct child of the equipment that the rule is attached to. |
Optional |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
30 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| Low Discharge Superheat Limit Threshold |
Numeric |
10 |
The pressure limit threshold. |
2.1.31.1- Chiller Continuous Operations at High Load
Summary
When the chiller is consistently operated at a load greater than its threshold.
| Equipment Type |
Equipment Tag Constraints |
Tuple Constraints |
| chiller |
-- |
-- |
Input Points
| Name |
Point Template |
Positional Requirements |
Optionality |
Multiplicity |
| Chiller Status |
ChrSts |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
| Chiller Load |
ChrLoad |
This point must be a direct child of the equipment that the rule is attached to. |
Mandatory |
Scalar |
Input Constants
| Name |
Data Type |
Default Value |
Description |
| Delay |
Numeric |
240 |
The delay represents a span of time in minutes during which the chiller must be in a fault state before the rule starts to actually report that it is in a fault state. The intent of the delay is to reduce the level of alert noise by ensuring that the system does not alert until the fault condition has been in effect for some minimal interval of time. |
| Chiller Max Load Threshold |
Numeric |
95
|
The pressure limit threshold. |
