This checklist identifies Key Commissioning Test Requirements and Key Preparations and Cautions for testing constant flow pumping systems. When writing a test, use this checklist to help ensure that these key areas have been covered. The buttons following the checklist items link to supporting information within the Functional Testing Guide and the Control System Design Guide.
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Key Commissioning Test Requirements
- ___ 1. The following are considered “prefunctional” checks that should be completed and verified prior to performing a functional test (note that this is not a comprehensive list of all prefunctional checks):
- a) Individual coils and/or distribution piping are flushed and pressure tested (when required).
- b) All safeties, interlocks, and alarms are programmed (or hard-wired, if applicable) and function correctly.
- c) Sensor installation and calibration is sufficient to achieve the design control strategies.
- d) Proper stroke for control valves (coil valves, isolation valves, etc.) is verified to ensure that they open and close completely.
- e) Control valve leakage testing reveals no detectable leakage when valve is commanded closed.
- f) 3-way control valves modulate correctly.
- g) Review TAB report, including flow, impeller size, and motor volt/amp measurements.
A pump performance test has been conducted to achieve the following objectives (this test should be performed if the pump appears oversized based on the TAB report and physical inspections):
- ___ 2. The impeller size has been verified.
- ___ 3. The system curve for the pumping system has been established.
- ___ 4. The operating points of the pump on the system curve with the discharge valve throttled to design flow, and with the discharge valve fully open, have been established.
- ___ 5. The match between the flow delivered by the pump with the discharge valves fully open and the actual head required to deliver design flow requirement have been assessed.
- ___ 6. If the pump capacity with the discharge valve wide open exceeds requirements, opportunities to trim the impeller or add a variable frequency drive (VFD) to reduce flow and save energy have been evaluated.
- ___ 7. The flow variations produced in the system as valves open and close have been assessed.
The control sequences have been tested to achieve the following objectives:
- ___ 8. Proper distribution pump staging is verified per the sequence of operations.
- ___ 9. Proper control sequence and integration is verified over all components (such as setpoints, start-up/shut-down procedures, and time delays). This includes verifying proper stand-by pump operation if the case of a lead pump failure.
- ___ 10. Verify that condenser pumps and primary chilled and hot water pumps are started and proof of flow is established prior to the respective equipment being enabled.
Key Preparations and Cautions
- 1. Construction prefunctional checklists should be completed throughout construction during normal commissioning site visits as installation of the various components and systems are completed. Sensor and actuator calibration is typically considered to be part of the construction prefunctional checklist.
- 2. In addition to the construction prefunctional checklists, all component start-up procedures must be complete in order to conduct functional test procedures. Water-side TAB must also be complete prior to functional testing.
- 3. Valve leakage tests and tests that are targeted at verifying valve stroke, spring range, and sequencing should be conducted with the pumping system operating at its peak differential pressure. The differential pressure across the valve plug can have a significant impact on the close-off rating and shift the operating spring range of the valve. These tests should be performed prior to temporary system operation to ensure that equipment will not be damaged during functional testing.
- 4. Ideally, functional performance testing of a constant flow water system should occur during the season in which the system is intended to operate (hot water in winter and chilled water in summer) to observe the entire system under normal operating conditions. If this is not possible due to the construction schedule, system operation and performance must be verified by either creating false loads on the equipment or through manipulation of setpoints to accommodate existing atmospheric conditions. For example, a load can be simulated by adjusting all setpoints to be 10°F above or below current ambient conditions and allowing the system to respond accordingly.
- 5. Successful execution of the constant flow water system functional tests is dependent on the operation of ancillary equipment (air handling units, heat pumps, process loads, chillers, boilers, cooling towers). At a minimum, the construction prefunctional checklists should be completed on the components/systems served by the water system and should be capable of safe temporary operation.
- 6. If testing a condenser water system during cold weather conditions, be sure all freeze protection controls operate as intended to prevent operational problems.
- 7. Safety and interlock tests, as well as some test procedures and loop tuning efforts (for example, high/low limit cut-out setpoints, emergency shut-down procedures, and failure/back-up system operation) can place the system at risk if the sequences do not function as intended. Appropriate precautions and procedures should be in place to protect personnel and machinery, including plans for quickly aborting the test if necessary.
- 8. Rapid stroking of valves during a test process can cause water hammer problems in the piping systems. Consider stroking each valve in stages to prevent slamming valves open or closed, giving the system time to respond appropriately.
- 9. It is recommended that any reset strategies be disabled first and that only one control parameter be varied at a time so that basic system operation can be verified. Reestablish the resets for other control parameters progressively and verify system operation remains stable.
Page last updated: September 11, 2006