Reversing Valve; Touch Testing Heating/Cooling Cycle; Procedure For Changing Reversing Valve - Friedrich H)A09K25L Service Manual

When sluggish or stuck in the mid-position, part of the
discharge gas from the compressor is directed back to the
suction side, resulting in excessively high suction pressure.
Should the valve fail to shift from coooling to heating,
block the air flow through the outdoor coil and allow the
discharge pressure to build in the system. Then switch the
system from heating to cooling.
If the valve is stuck in the heating position, block the air
flow through the indoor coil and allow discharge pressure
to build in the system. Then switch the system from heating
to cooling.
Should the valve fail to shift in either position after increasing
the discharge pressure, replace the valve.
Dented or damaged valve body or capillary tubes can
prevent the main slide in the valve body from shifting.
If you determing this is the problem, replace the reversing
valve.
After all of the previous inspections and checks have been
made and determined correct, then perform the "Touch
Test" on the reversing valve.
Reversing Valve in Heating Mode
Reversing Valve in Cooling Mode
26
Touch Test in heating/Cooling Cycle
WARNING
BURN HAZARD
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.
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 31, indicate that the reversing valve is not shifting
properly. Both tubes shown as hot or cool must be the same
corresponding temperature.

Procedure For Changing 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 protect surrounding areas with fire proof materials.
Have a fire extinguisher readily available. Failure to follow
this 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, 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.