This checklist identifies Key Commissioning Test Requirements and Key Preparations and Cautions for an air-handling system. 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. During design review, the following items were addressed to avoid issues during functional testing:
- a) Sensor installation and calibration is sufficient to achieve the design control strategies.
- b) Proper control of heating coil, economizer, and cooling coil are verified in each air handler.
- c) Proper supply fan VFD control static pressure setpoint is verified in variable-air-volume systems.
- d) The maximum setpoint does not exceed the specified design pressure value.
- e) Proper coordination between individual setpoints and reset strategies is verified. For example, the discharge air temperature reset and discharge static pressure reset control strategies are coordinated.
- a) Sensor installation and calibration is sufficient to achieve the design control strategies.
- ___ 2. The following "prefunctional" checks were 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 in both automatic and manual operating modes.
- b) Outdoor, return, and exhaust dampers open, close, and modulate as intended per the specified economizer and building pressure control strategies.
- c) Control valves open, close, and modulate as intended in order to maintain stable air temperature control under all flow conditions.
- d) Control valves close off completely.
- ___ 3. The preheat, heating, and/or cooling coils meet the manufacturer's stated part load performance under the actual test conditions.
- ___ 4. Outdoor air ventilation is maintained at or above the minimum specified value as supply air flow varies to meet system load in variable-air-volume systems.
- ___ 5. Proper supply and return fan control is verified per specified sequence of operations, including (but not limited to): morning warm-up; building pressure control; heating and cooling mode; economizer mode; and fire/life safety mode.
- ___ 6. The system operates and maintains discharge air temperature setpoint in all operating modes including Morning Warm-up, Occupied/Unoccupied mode, and Night Low Limit mode.
- ___ 7. Static pressure reset control strategy is verified in variable-air-volume systems.
- ___ 8. The discharge air temperature reset control strategy is verified.
- ___ 9. Proper control sequence and integration is verified over all associated components (including start-up/shut-down procedures and time delays as well as setpoints and reset strategies).
- ___ 10. Control algorithms generate the proper setpoints based on the reset parameters.
- ___ 11. PID control loops achieve stability within a reasonable amount of time (typically 2 to 5 minutes) after a significant load change (such as start-up, or automatic or manual recovery from shut down).
- ___ 12. Operation of the air handling unit being tested does not create an unstable operating condition in any other system serving, or operating adjacent to, the unit (such as chillers, boilers, distribution pumping, terminal units, and other air handling units). This is typically best addressed through system trending under normal operating conditions.
Key Preparations and Cautions
- 1. Prefunctional checks should be completed on the components/systems serving the air handling system (including terminal units, chillers, boilers, and distribution pumps) in order to conduct functional test procedures. Prefunctional checks include, but are not limited to: completion of factory start-up procedures; smoke-fire dampers are operational; control system checkout and programming is complete; duct access doors are closed; and hydronic systems have been flushed and properly filled. In addition to prefunctional checklists, both the air-side and water-side TAB must also be complete prior to functional testing.
- 2. Safety and interlock tests, as well as some test procedures and loop tuning efforts (for example, high/low limit cut-out set points, 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.
- 3. Typically, individual components of the air handling system require testing under specific atmospheric conditions (for example, test reheat/heating coil in winter, cooling coil in summer, and economizer during swing months). If functional performance testing cannot be completed in all seasons in order to fully observe the system under normal operating conditions, system performance may still be verified by either creating false loads on the equipment or through manipulation of setpoints to accommodate existing atmospheric conditions.
- 4. Depending on when functional testing occurs, one or more control strategies may need to be tested during off-peak conditions (i.e., heating in summer and cooling in winter). Be aware of the potential impact that atypical air temperatures delivered by the unit being tested may have on the building and occupants within the respective zones. Construction work in these areas could be adversely affected if the space temperature deviates significantly from a tolerable level.
- 5. Discharge air temperature setpoint and reset schedule must be coordinated with the chilled and hot water temperature setpoints.
- 6. All resets, except the one being tested, should be overridden to prevent unwanted system interaction during testing. Once the individual reset control strategy has been verified, trending should be used to verify proper interaction and integration between the various control strategies.
- 7. Ensure that the minimum and maximum design air flow values for each terminal unit are programmed correctly prior to supply fan testing. Improper terminal unit control can lead to significant control and performance problems at the air handling unit.
- 8. Indoor air quality may not be maintained without attention to achieving design outside air flow at part-load conditions. As the supply fan slows down to meet reduced demand, the amount of outdoor air introduced into the supply air stream may also reduce (depending on the pressure in the mixed air plenum). Proper outdoor air flow can be achieved by a variety of "active" control methods, including modulation of the economizer dampers, modulation of dedicated outdoor air dampers, or through the use of an independent ventilation fan system.
- 9. The desired pressure relationship between inside and outside conditions should be maintained or there can be a large impact on infiltration. Unwanted air migrating into the building can result in significant energy waste as well as lead to potential comfort and moisture problems.
Page last updated: September 11, 2006