Friedrich PDE07K Series, Service & Parts Manual

Page: 87 / 130

87 PB
COMPONENT TESTING
Replace The Reversing Valve
WARNING
HIGH PRESSURE HAZARD
Sealed Refrigeration System contains refrigerant
and oil under high pressure.
Proper safety procedures must be followed,
and proper protective clothing must be worn
when working with refrigerants.
Failure to follow these procedures could
result in serious injury or death.
NOTICE
FIRE HAZARD
The use of a torch requires extreme care and proper
judgment. Follow all safety recommended precautions and
notice could result in moderate to serious property damage.
1. Install Process Tubes. Recover refrigerant from sealed system. PROPER HANDLING OF RECOVERED
REFRIGERANT ACCORDING TO EPA REGULATIONS IS REQUIRED.
2. Remove solenoid coil from reversing valve. If coil is to be reused, remove solenoid and protect from heat while
changing valve.
3. Unbraze all lines from reversing valve.
4. Clean all excess braze from all tubing so that they will slip into fittings on new valve.
5. Remove solenoid coil from new valve.
6. Protect new valve body from heat while brazing with plastic heat sink (Thermo Trap) or wrap valve body with
wet rag.
7. Fit all lines into new valve and braze lines into new valve.
WARNING
EXPLOSION HAZARD
The use of nitrogen requires a pressure
regulator. Follow all safety procedures and
wear protective safety clothing etc.
Failure to follow proper safety procedures
could result in serious injury or death.
8. Pressurize sealed system with a combination of R-410A and nitrogen. Pressurize system to 550 psi and triple
evacuate. Check for leaks, using a suitable leak detector. Recover refrigerant per EPA guidelines.
9. Once the sealed system is leak free, install solenoid coil on new valve and charge the sealed system by
weighing in the proper amount and type of refrigerant as shown on rating plate. Crimp the process tubes and
solder the ends shut. Do not leave Schrader or piercing valves in the sealed system.
NOTE: When brazing a reversing valve into the system, it is of extreme importance that the temperature of the
valve does not exceed 250°F at any time .
Wrap the reversing valve with a large rag saturated with water. “Re-wet” the rag and thoroughly cool the valve
after each brazing operation of the four joints involved.
The wet rag around the reversing valve will eliminate conduction of heat to the valve body when brazing the line
connection.