Compressor repair with no Ex zone - exchange valve plate

Example task: Exchange of a valve plate on a semi-hermetic reciprocating compressor operated with A2L refrigerant R454C. The compressor is located on a rack in a machinery room.

Special tools or preconditions:

• Mobile A2L gas detector
• A2L leak detector
• A2L fire extinguisher
• A2L recovery equipment
• Vacuum pump with external switch, outside room
• Extra fan
• A2L anti-sparking tool – not necessary
• Avoid Ex zone! Avoid / check for leakage!

Working steps or preconditions:

1. Educated worker
2. Read / inform for risk assessment of system
3. Have A2L fire extinguisher ready
4. Put warning sign to notify work in progress, especially where refrigerant might be released
5. Power off compressor / system
6. Ventilation on
7. a. Install extra fan
7. Go in with gas detector / check regularly with gas detector or machinery room detector
8. Close compressor shut off valves
9. Release pressure
10. a. Small gaseous amount to marked outside area
10. Oil heater on
11. Evacuate compressor
12. a. Release vacuum pump outlet to marked outside area
12. Charge compressor with Nitrogen
13. Open compressor and replace valve plate
14. a. Observe gas concentration at working place with mobile gas detector
15. b. Stop work, if gas concentration reaches alarm level and wait for ventilation!
14. Close compressor
15. Check tightness with dry Nitrogen
16. Evacuate compressor
17. Open compressor shut off valves
18. Remove warning signs
19. Take compressor into operation again