This checklist identifies Key Commissioning Test Requirements and Key Preparations and Cautions for testing air-cooled condensers and related systems. (Evaporative condensers are covered in the Cooling Tower checklist.) 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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Control System Design Guide |
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) All safeties, interlocks, and alarms are programmed (or hard-wired, if applicable) and function correctly, including low-ambient controls for condenser fans.
- b) Proper sensor installation and calibration is verified.
- c) Fan motors spin in the correct direction and do not have abnormal noise or vibrations.
- d) Refrigerant piping installed per the specification
- e) Refrigerant system has been pressure tested, evacuated, and properly charged per the specifications
- ___ 2. Proper condenser control and staging is verified, especially if multiple units are installed.
- ___ 3. Verify head pressure setpoint and optimize if necessary. Typically this is only applicable to air-cooled condensers serving large chiller and refrigeration systems (not package HVAC systems with air-cooled condensers).
- ___ 4. Proper head pressure control and integration is verified over all components.
- ___ 5. All control loops achieve stability within a reasonable amount of time after a significant load change.
Key Preparations and Cautions
- 1. Prefunctional checklists should be completed throughout construction during normal commissioning site visits as various components and systems are installed. Sensor and actuator calibration is typically considered to be part of the prefunctional checklist. Verification that refrigerant piping is installed, pressure tested, and evacuated per design and manufacturer's recommendations also occurs as a part of the prefunctional checklist.
- 2. In addition to the prefunctional checklists, all component start-up procedures must be complete in order to conduct functional test procedures. Both the air-side and water-side TAB must also be complete prior to functional testing.
- 3. Several points should be noted to avoid testing complications:
- a) Functional performance testing for an air-cooled condenser system can occur during virtually any atmospheric conditions except, perhaps, during extreme cold (unless the system is intended to operate even when outside air temperature is low, such as an HVAC system serving a 24/7 computer room load or a large refrigeration system). Testing some control sequences, like low-ambient head pressure controls, can only be accurate when proper atmospheric conditions exist. Therefore, complete performance verification may require a phased-testing approach to check system operation under various ambient conditions. Care should be taken to ensure that testing conditions will not have an adverse impact on the equipment.
- b) The minimum required system head pressure is based on the minimum pressure that will guarantee liquid refrigerant is available at an individual thermal expansion device. Often a liquid pump may be necessary to boost the pressure of the refrigerant in the system to ensure liquid refrigerant is supplied to the expansion device if the head pressure control strategy is aggressively optimized. Use caution if optimizing head pressure controls during commissioning.
- c) Safety and interlock tests, as well as some test procedures and loop tuning efforts (for example, high or low refrigerant cut-out setpoints, emergency shut-down procedures, and failure/back-up system operation) could 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.
Page last updated: September 11, 2006