Maintenance & Reliability · SOP
Commercial Chiller Startup Sequence And Refrigerant Leak Check
This SOP covers the step-by-step startup procedure for a water-cooled or air-cooled commercial chiller, including a mandatory refrigerant leak check using electronic and bubble detection methods. Designed for facilities maintenance teams working with R-134a, R-410A, or similar HFC refrigerants.
Estimated Time
90 min
Difficulty
Intermediate
Regulation
CSA B52 / ASHRAE 15
Version
1.0
Purpose
To provide a standardized, repeatable procedure for safely bringing a commercial chiller online after a scheduled shutdown or maintenance event, and to perform a refrigerant leak check that satisfies regulatory compliance and minimizes the risk of environmental release. A documented leak check also helps extend compressor life and maintain system efficiency.
Scope
This procedure applies to all commercial chillers in the facility with a refrigerant charge greater than 50 lbs (22.7 kg) and operating pressures below 400 psig. It covers single- and dual-circuit compressors (scroll, screw, or reciprocating) using HFC refrigerants. Does not cover ammonia or CO₂ systems, nor chillers under major overhaul (e.g., compressor replacement).
Safety Precautions
- Lockout/Tagout on all power sources (480V, 208V, control voltage) before opening any access panels. Verify zero energy with a calibrated voltage tester.
- Wear insulated Class 00 gloves, safety glasses with side shields, and steel-toe boots. For leak check operations, also wear chemical-resistant gloves if handling refrigerant oils.
- Refrigerant can cause frostbite and asphyxiation. Ensure adequate ventilation and use a refrigerant recovery cylinder if a leak is confirmed. Do not breathe refrigerant vapours.
- Never exceed component maximum working pressure. Monitor suction and discharge pressures continuously during startup. Rapid pressure rise may indicate a blockage or faulty expansion valve.
Required Tools & Materials
- Electronic refrigerant leak detector (Robinair TIF ZX+ or equivalent, calibrated within 30 days)
- Bubble detection solution (Big Blu or equal)
- Manifold gauge set with low-side and high-side hoses
- Thermometer (thermocouple or infrared), ±0.5°F accuracy
- Calibrated voltage tester (CAT III / CAT IV)
- Flashlight, inspection mirror, step ladder
- Refrigerant recovery cylinder and recovery machine (on standby if leak found)
- Torque wrench for service valve caps
- Safety glasses, insulated gloves, chemical-resistant gloves
- PM log sheet / digital CMMS tablet (e.g., ServiceGrid)
Procedure: Step-by-Step
1
Pre‑Start Inspection: Visual inspection of compressor, condenser, evaporator, expansion valve, piping, and electrical connections. Verify oil level within the compressor sightglass (mark level). Check for visible corrosion, loose bolts, or refrigerant oil stains around joints. Ensure all isolation valves (suction, discharge, liquid line) are in the correct position per manufacturer manual.
2
Lockout/Tagout (LOTO) Verification: Confirm LOTO is applied on the main disconnects and control panel. Test for zero energy using a calibrated voltage tester. Do not proceed until power is verified off. Only after verification, open access panels.
3
Power Up Chiller Controller: Remove LOTO and re‑energize the chiller control panel. Observe the controller boot sequence. Note any fault codes or alarms on the HMI. Record them on the PM log. Clear non‑critical alarms if allowed by site policy.
4
Set Operating Parameters: Enter the chilled water setpoint (typically 44°F / 6.7°C), condenser water setpoint (if applicable), and operating mode (cooling). Verify the setpoints match the building automation system (BAS) requirements. Enable load limiter if multiple chillers.
5
Start Compressor – Manual Mode: Initiate compressor start via the controller (manual override). Monitor amp draw on each phase and compare to motor nameplate FLA. Observe suction and discharge pressures for 5 minutes. Verify no abnormal vibration, noise, or excessive superheat (target 8–12°F). Record steady‑state values.
6
Refrigerant Leak Check – Electronic Detector: With the system running at normal operating pressures, use the calibrated electronic leak detector to scan all accessible joints, service ports, flanges, valve stems, and evaporator/condenser connections. Move the sensor at 1 inch per second, keeping it within ¼ inch of the surface. Mark any locations where the detector alarms.
7
Refrigerant Leak Check – Bubble Test: For suspected leaks (from step 6) and high‑risk areas (valve cores, Schrader ports, flare joints), apply a small amount of bubble detection solution using a squeeze bottle. Wait 30 seconds. If bubbles form, note the location, size, and severity on the PM log. Use a mirror for hidden areas.
8
Record Data & Shutdown Sequence: Log all final operating parameters: suction/discharge pressure (psig), saturated temperature, superheat, subcooling, amp draw, water in/out temperatures. If no leaks found, proceed to shutdown: stop compressor, allow equalization, then cycle the pump down if equipped. Close isolation valves if the chiller will be idle for more than 24 hours.
9
Final Verification & Restore: If a leak was repaired (using approved procedures), repeat the leak check steps (6 and 7) after repair. Restore chiller to auto mode. Confirm normal operation for 15 minutes. Complete the PM log with technician signature, date, and any recommendations. Return the chiller to service.