Equipment Commissioning Procedures Reference

Why this matters

Commissioning is the systematic process of verifying that newly installed equipment operates per design before customer acceptance. Skipping it produces "installed and forgot it" systems with hidden problems - undersized airflow, undercharge, miswired control, leaks at fittings. Commissioning takes 30-90 minutes per install and is what separates installations that operate at nameplate vs ones that limp along. ASHRAE Guideline 0 and ACCA QI standards both require commissioning as part of quality installation.

The four phases of commissioning

1. Planning - before equipment selection / install. Define commissioning scope, responsibilities, and acceptance criteria.

2. Construction-phase verification - during install. Verify materials match spec, installation methods follow code and manufacturer requirements.

3. Startup commissioning - at energization. Verify equipment starts, operates within design parameters, controls function.

4. Acceptance - formal sign-off. Customer accepts the equipment as commissioned; warranty starts.

For residential service work, the commissioning is usually steps 3 and 4 (with step 2 informally during install).

Pre-startup checklist

Before energizing or pressurizing:

Mechanical (HVAC):

• All conductors landed and torqued per spec
• Refrigerant lines brazed with nitrogen purge
• Refrigerant system evacuated (≤500 microns, decay test passed)
• All fittings checked for leaks
• Drain pan and condensate drain installed
• All access panels closed
• Owner's manual reviewed for any startup procedures

Electrical:

• Service connection verified
• Conductors sized correctly
• All terminations torqued
• Ground continuity verified
• Phase rotation correct (3-phase)
• Working clearance per NEC 110.26

Plumbing:

• Supply lines pressure-tested
• DWV system tested (air or water test)
• Backflow protection in place
• Fixtures correctly installed
• Drain slopes correct

Controls / BMS:

• Wiring correct per schematic
• Sensors calibrated or factory-set
• Programming uploaded
• Communication established with BMS

HVAC startup commissioning procedure

For a residential split AC / heat pump:

Step 1: Initial energization

1. Restore power; verify nameplate voltage at compressor and air handler
2. Turn on thermostat; verify call signal reaches air handler
3. Listen for normal startup sequence - blower starts, no unusual noises

Step 2: Refrigerant system verification

1. Connect manifold to service ports
2. Run system 15-20 minutes at full capacity (typical 75 °F indoor, 95 °F outdoor for cooling)
3. Read suction pressure, discharge pressure
4. Read suction line temp, liquid line temp
5. Calculate superheat (SH) and subcooling (SC)
6. Compare to manufacturer target (typical SC 8-12 °F for TXV)
7. Adjust charge if needed (small increments)

Step 3: Electrical verification

1. Measure compressor amperage (compare to nameplate FLA)
2. Measure condenser fan amperage
3. Measure blower amperage
4. Verify capacitor function (if PSC blower)

Step 4: Airflow verification

1. Measure return air temperature
2. Measure supply air temperature
3. Calculate ΔT (typical 18-22 °F for cooling)
4. Measure total external static pressure (TESP) - should be ≤0.5 in. w.c.
5. Verify CFM matches design (often calculated from temperature differential)

Step 5: Drainage verification

1. Pour water into condensate drain
2. Verify it flows freely to termination
3. Check trap is wet (water seal)
4. Check overflow safety switch (if equipped)

Step 6: Operational tests

1. Run heat call (if heat pump or with backup heat)
2. Verify aux heat / strip if applicable
3. Cycle compressor off, verify gradual shutdown
4. Verify no oil residue or leak at compressor

Step 7: Documentation

• Record all measurements
• Photograph manifold readings
• Write up the commissioning report

Plumbing system commissioning

For a major plumbing install (full repipe, new bathroom):

Step 1: Pressure test the supply side

• Air test or water test at 1.5× working pressure (typically 100 psig for water, 50 psig for air)
• Hold for 15-30 minutes
• Verify no pressure drop = no leak

Step 2: Test the DWV side

• Plug all outlets except one for testing
• Fill with water to roof vent (water test) OR pressurize to 5 psi air
• Hold 15 min - no leaks

Step 3: Operational checks

• Run every fixture; verify supply pressure
• Verify drain flow (no slowness)
• Verify hot water reach (water heater functioning, mixing valves correct)
• Verify cleanouts accessible
• Verify all shutoffs work

Step 4: Documentation

• Photos of test gauges holding pressure
• Written report
• Customer signature on acceptance

Electrical system commissioning

For a new electrical service or major sub-panel:

Step 1: De-energized verification

• Verify all conductor connections torqued to spec
• Verify all conductor identification correct (color codes, phase markings)
• Verify grounding electrode system per NEC 250
• Verify sub-panel bond removed (if sub)
• Verify working clearance per NEC 110.26

Step 2: Insulation resistance test (Megger)

• Disconnect line-side
• Test each phase to neutral and phase to ground
• Expect >100 MΩ for new wiring
• Document readings

Step 3: Energization

• Energize with main off
• Bring main breaker on
• Verify voltage at each phase to neutral (≈120 V) and phase to phase (≈208 or 240 V)
• Verify phase rotation (3-phase systems; rotation matters for motors)

Step 4: Branch circuit verification

• Turn on each branch breaker
• Verify voltage at each receptacle / equipment (with plug-in tester for proper polarity)
• Verify GFCI / AFCI trip and reset
• Verify equipment functions normally

Step 5: Documentation

• Photo of panel with all breakers labeled
• Megger readings
• Phase voltage measurements
• Customer signature

Controls commissioning (BMS / BAS for commercial)

For modern building controls:

Point-to-point checkout:

• Verify each sensor reads correctly (correct calibration, no random values)
• Verify each actuator responds to control signal
• Verify each control loop reaches setpoint

Sequence-of-operations verification:

• Walk through the control logic per manufacturer
• Trigger events (call for heat, call for cool, occupied vs unoccupied)
• Verify system response

Trending:

• Configure BMS to record key parameters
• Run for 24-48 hours
• Review for anomalies

Customer training:

• Walk through the BMS interface
• Show how to schedule, override, view trends
• Provide user manual

Verification standards

ASHRAE Guideline 0: The Commissioning Process. Standard reference for commissioning practice.

ASHRAE Standard 202: Commissioning Process for Buildings and Systems.

References

• ASHRAE Guideline 0 (Commissioning Process)
• ASHRAE Standard 202 (Commissioning Process for Buildings)
• ACCA QI Standard (HVAC quality installation)
• BSCC Commissioning Handbook
• LEED v4 (Commissioning credit requirements)
• ANSI/ICC 700 (National Green Building Standard)
• Manufacturer install manuals (always include startup procedures)