Chilled Water System – Pump is operating with chillers OFF

Objective/ Method/Outcome

Objective: Determines if the pump is operating while chillers are inactive.

Method: Compares the pump status signal to chillers status signals and generates an insight when this fault occurs for greater than the defined daily threshold. Avoidable Cost and Potential Savings are determined by calculating unnecessary pump energy consumption.

Outcome: This rule generates an insight.

Description

Reference: ASHRAE Guideline 36-5.20.6.6 This rule determines if pump is overrunning when chillers is OFF. Free cooling from cooling tower is an exception. This rule is applied for pump. This rule is part of the CopperTree Standard rule-set.

Default Priority

High

Diagnosis

1. Inspect the equipment to see if it has been overridden manually.

2. Ensure that interfacing relays are working.

3. Verify that the status sensor is calibrated.

Message

The Chiller Pump is running out of sync with the Chiller Sequence. Please investigate the sequence of the Chilled Water System.

Rule Template

Insight Type: Fault Detection

Trigger Type: Active High

Notes

1. Expected values for “Pump Status” inputs are “0” or “1”.

2. Expected values for “Chiller Status” inputs are “0” or “1”.

3. Expected values for “Pump Speed” inputs are “100” if they are constant speed pumps or not available.

4. The input(s) that is(are) not used should be set to “0”.

Default Values:

Const. – Acceptable Daily Hours of Faulty Operation [hours]: 2

Const. – Pump Rating [HP]: 10

Const. – Electricity Rate [$/kWh]: 0.1

Const. – Weeks of Operation: 26