This checklist identifies Key Commissioning Test Requirements and Key Preparations and Cautions for the terminal equipment associated with an air handler. 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.
Link Legend:
 |
Test Guidance |
 |
Tips |  |
Typical Problems |
 |
Design Issues |
 |
Control System Design Guide |
Key Commissioning Test Requirements
Key Component Test Requirements
Component-level functionality can be verified through spot-checking randomly selected units.
- ___ 1. The functional testing sampling plan includes a sufficient percentage of terminal units, and all types of units are included in the sample.
- ___ 2. 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) The terminal unit passes static inspection, and the contractor has completed the necessary items from the construction checklist.
- b) The sensors (typically space temperature and terminal unit air flow) are calibrated, and the reading at the building automation system is within the limit specified when compared to the test instrument-measured value.
- c) The strainer is clean and the water loop is clear of debris that may prevent design water flow through the coil.
- d) The reheat coil design flow rate is met.
- e) Three-way valves are checked for proper installation, set-up, and programming (if present).
- f) If the terminal unit has a hot water valve that does not provide position feedback to the BAS, heating water valve calibration to actuator position is verified.
- a) The terminal unit passes static inspection, and the contractor has completed the necessary items from the construction checklist.
- ___ 3. Terminal unit checks include the following:
- a) Documentation
- b) Cooling minimum and maximum flow rate setpoints
- c) Heating minimum and maximum flow rate setpoints
- d) K-factor (flow coefficient)
- e) Zone temperature adjustment range
- f) Occupied cooling and heating zone temperature setpoints
- g) Unoccupied cooling and heating zone temperature setpoints
- h) Heating coil valve stroke rate for incremental valves
- i) Cooling space temperature setpoint proportional band
- j) Heating space temperature setpoint proportional band
- k) Primary air damper proportional band
- l) Damper stroke time (value comes from controller specification/cut sheet)
- m) Duct area inlet
- n) Auto-zero function schedule (set and enable)
- ___ 4. The heating coil valve closes fully and does not leak water through the valve.
- ___ 5. Unit performance is verified by automated terminal unit diagnostics.
Key System Test Requirements:
System-level testing verifies that terminal units respond according to the sequence of operations. These tests are performed primarily by changing setpoints and observing response in the control system.
- ___ 6. The ability of the terminal unit to respond to zone cooling and heating loads is verified.
- ___ 7. The stability of the heating coil valve control loop is verified.
- ___ 8. Space temperature stability is verified. The space is kept within ±1°F of setpoint at all times, except during air handler start-up.
- ___ 9. Demand-controlled ventilation performance at the zone level (if present) is verified. For example, the VAV box minimum flow rate is reset baced on CO2 concentration.
- ___ 10. Occupancy sensor control is verified (if present). For exemple, zone temperature setpoint and/or VAV box minimum flow rate is reset based on an occupancy signal.
- ___ 11. Unoccupied and override control are verified.
- ___ 12. Night low limit and night high limit control sequences are verified. Note that these sequences are typically different for fan-powered terminal units than for non-fan-powered units.
- ___ 13. Morning warm-up cycle and morning pre-cool cycle control sequences are verified.
- ___ 14. The integration of the terminal unit control with the AHU fan speed control is verified.
- ___ 15. Reheat is minimized. Note that excessive airflow may cause excessive reheat. During design review, verify that VAV box minimum flow rates are acceptable to meet design loads. Prior to functional testing, verify the minimum flow rate setting in the BAS control system is programmed per design. During functional testing, use trends to help identify excess reheat. One option to minimize reheat is to lower the minimum flow rate setpoints, especially if actual occupancy is less than design.
- ___ 16. Proper coordination and sequence of operations between zonal heat (i.e. finned tube, radiant panels, etc) and VAV box flow rate/reheat is verified, if applicable.
- ___ 17. For VAV boxes with electric resistance reheat, it may be necessary to check ALL units for proper minimum air flow rate to ensure the heating element will operate correctly. Many VAV boxes with electric reheat may require a manual reset if the heating element shuts down due to inadequate flow across the coil. This safety may not be caught if a sampling plan is utilized and minimum flow rate is not checked for each box.
Key Preparations and Cautions
- 1. Testing the terminal equipment will affect the conditions in the zone under test and may generate unacceptable zone conditions, especially if the unit fails the test. The potential impact of testing on zone conditions should be considered when planning and scheduling testing and may preclude testing with the zones occupied.
- 2. Design and installation problems can be quickly replicated across hundreds of units due to standard detailing and installation practices. Similarly, a test procedure that has a bug can be replicated across the units. Therefore, it is advisable on projects with many zones to test run test procedures prior to replicating the necessary paperwork.
- 3. Due to high zone counts, problems uncovered during terminal unit testing can rapidly escalate into a significant time commitment to resolve.
- 4. Most terminal unit tests will manipulate the various settings in the units to force certain operating conditions and observe the results. It is critical that all parameters are returned to the correct settings and that the terminal units are verified as resuming normal function following the test. This is important with any functional test, but especially critical for terminal units since they have such a direct impact on zone comfort, indoor air quality, and on the efficiency of the air handling system serving them.
- 5. Testing a VAV box may require the use of ladders or perhaps mechanical lifts to reach the unit. Proper safety precautions should be adhered to when working in an elevated position.
Page last updated: September 11, 2006