Test Comments
The following acceptance test procedures are applicable to systems controlled by individual thermostats, internal DDC, or central DDC systems. Most of the tests can be performed through simple manipulation of the individual thermostat or the DDC system controlling each packaged HVAC unit. Specific details and examples of how to perform each test are provided below.
Construction Inspection
Prior to Functional Testing, verify and document the following:
Thermostat, or temperature sensor, is located within the zone that the respective HVAC system serves.
Thermostat is wired to the HVAC unit correctly. Note that this can be inferred from the acceptance tests.
•In particular, ensure that multiple stage terminals (i.e., 1st and 2nd stage wires) on the thermostat, both cooling and heating stages, are wired to the corresponding circuits at the HVAC unit.
•Verify that no factory-installed or field-installed jumpers exist across the 1st and 2nd stage cooling terminals at the unit (this will ensure that only the economizer can be enabled as the 1st stage of cooling).
•For heat pump only, verify the “O” terminal on the thermostat is wired to the reversing valve at the unit.
•For heat pump only, verify thermostat dip switch or programmable software is set to heat pump.
•Thermostat meets the temperature adjustment and dead band requirements of §120.2(b): The thermostat shall allow a heating setpoint of 55°F or lower and a cooling setpoint of 85°F or higher. The deadband shall be at least 5°F, where heating and cooling is shut off. On the Acceptance Form MECH-04A, note the minimum heating setpoint, maximum cooling setpoint, and deadband.
•Occupied, unoccupied, and holiday schedules have been programmed per the facility’s schedule
Pre-occupancy purge has been programmed to meet the requirements of §120.1(c)2. This is typically accomplished by scheduling the unit to start one hour prior to actual occupancy. Check the method used to determine pre-occupancy purge:
•The lesser of 15 cfm per person, or the conditioned floor area times the ventilation rate from the Building Energy Efficiency Standards Table 120.1-A.
•Three complete building air changes (ACH)
Functional Testing
The following procedures are applicable to systems controlled by a programmable thermostat, internal DDC (packaged systems only), or central DDC system.
As you complete each step, check the appropriate operating mode boxes on the Acceptance Form.
Step 1: Disable economizer control and demand-controlled ventilation systems (if applicable) to prevent unexpected interactions.
The economizer can be disabled by temporarily adjusting the high-limit setpoint. The demand-controlled ventilation system can be disabled by setting the CO2 setpoint well below current zone CO2 concentration.
Step 2: Simulate a heating demand during occupied condition.
•Either set the “occupied” time schedule to include actual time or adjust time to be within the “occupied” time schedule.
•Set heating setpoint above actual space temperature.
Verify and Document
•Supply fan operates continually during occupied condition.
•Ensure all available heating stages operate; the heater stages on. This may require raising the heating setpoint even further so that multiple heating stages can become enabled. For example, many programmable thermostats and DDC control algorithms use time delays and deviation from setpoint to enable multiple heating stages. Setting the heating setpoint very high should prevent the 1st stage of heat from meeting setpoint and allow the system adequate time to enable the 2nd or 3rd stages.
•No cooling is provided by the unit.
•Outdoor air damper is open to minimum ventilation position (Note: Outdoor ventilation air requirements will be tested under section NA7.5.1.2 Constant Volume System Outdoor Air Acceptance).
Step 3: Simulate operation in the dead band (no-load condition) during occupied condition.
•Set “occupied” time schedule to include actual time or adjust time to be within the “occupied” time schedule (whichever is easier).
•Adjust heating and cooling setpoints so that actual space temperature is between the two values.
Verify and Document
•Supply fan operates continually during occupied condition.
•Neither heating nor cooling is provided by the unit.
•Outdoor air damper is open to minimum ventilation position.
Step 4: Simulate a cooling demand during occupied condition.
•Set “occupied” time schedule to include actual time or adjust time to be within the “occupied” time schedule (whichever is easier).
•Set cooling setpoint below actual space temperature.
Verify and Document
•Supply fan operates continually during occupied condition.
•Ensure all available cooling stages operate; the compressor stages on. This may require lowering the cooling setpoint even further so that multiple cooling stages can become enabled. For example, many programmable thermostats and DDC control algorithms use time delays and deviation from setpoint to enable multiple cooling stages. Setting the cooling setpoint very low should prevent the 1st stage of cooling from meeting setpoint and allow the system adequate time to enable the 2nd stage.
•No heating is provided by the unit.
•Outdoor air damper is open to minimum ventilation position.
Step 5: Simulate operation in the dead band (no-load condition) during unoccupied condition.
•Set “unoccupied” time schedule to include actual time or adjust time to be within the “unoccupied” time schedule (whichever is easier).
•Ensure actual space temperature is in between unoccupied heating and cooling setpoints. Adjust each setpoint as necessary to achieve desired control.
Verify and Document
•Supply fan shuts OFF during unoccupied condition.
•Neither heating nor cooling is provided by the unit.
•Outdoor air damper is fully closed.
Step 6: Simulate heating demand during unoccupied condition.
•Set “unoccupied” time schedule to include actual time or adjust time to be within the “unoccupied” time schedule (whichever is easier).
•Set heating setpoint above actual space temperature.
Verify and Document
•Supply fan cycles on with call for heating.
•Heating is provided by the unit; heater stages on.
•No cooling is provided by the unit.
•Outdoor air damper is either fully closed or at minimum position
Step 7: Simulate cooling demand during unoccupied condition.
•Set “unoccupied” time schedule to include actual time or adjust time to be within the “unoccupied” time schedule (whichever is easier).
•Set cooling setpoint above actual space temperature.
Verify and Document
•Supply fan cycles on with call for cooling.
•No heating is provided by the unit.
•Cooling is provided by the unit.
•Outdoor air damper is either fully closed or at minimum position.
Step 8: Simulate manual override during unoccupied condition.
•Set “unoccupied” time schedule to include actual time or adjust time to be within the “unoccupied” time schedule (whichever is easier).
•Engage the manual override. This could entail pushing an override button, triggering an occupant sensor, or enabling some other form of override control.
Verify and Document
•System reverts back to an “occupied” condition. For a DDC control system, verify the “active” heating and cooling setpoints correspond to those programmed for the occupied condition. For a programmable thermostat, the thermostat may display that it is in the “occupied” mode.
•System reverts back to an “unoccupied” condition when manual override time period expires. It may be necessary to adjust the length of the override period to minimize test time.
•Check that supply fan operates continually during occupied condition.
•Check that outside air damper is open to minimum ventilation position.
Step 9: Return system back to normal operating condition.
Ensure all schedules, setpoints, operating conditions, overrides, and control parameters are placed back at their initial conditions. Confirm testing results on the Certificate of Acceptance form NRCA-MCH-03-A.