Friedrich KUHL R-410A - Manual (Page 46)

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8. Pressurize sealed system with a combination of R-410A
and nitrogen and 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.
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.
Procedure For Changing Reversing Valve
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, 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 fi ttings on new valve.
5. Remove solenoid coil from new valve.
The use of a torch requires extreme care and proper
judgment. Follow all safety recommended precautions
and protect surrounding areas with fi re proof materials.
Have a fi re extinguisher readily available. Failure to follow
this notice could result in moderate to serious property
damage.
NOTICE
FIRE HAZARD
Touch Test in Heating/Cooling Cycle
The only definite indications that the slide is in the mid-
position is if all three tubes on the suction side of the valve
are hot after a few minutes of running time.
NOTE: A condition other than those illustrated above, and
on Page 44, indicate that the reversing valve is not shifting
properly. Both tubes shown as hot or cool must be the same
corresponding temperature.
Certain unit components operate at
temperatures hot enough to cause burns.
Proper safety procedures must be followed,
and proper protective clothing must be
worn.
Failure to follow these procedures could
result in minor to moderate injury.
WARNING
BURN 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.
WARNING
EXPLOSION 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.
WARNING
HIGH PRESSURE HAZARD