Compressor Checks; Locked Rotor Voltage Test; Single Phase Connections; Determine Locked Rotor Voltage - Friedrich H)A09K25L Service Manual

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-22
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.

COMPRessOR CheCks

WARNING
ELECTRIC SHOCK HAZARD
Turn off electric power before service or
installation. Extreme care must be used, if it
becomes necessary to work on equipment with
power applied.
Failure to do so could result in serious injury or
death.
Locked Rotor Voltage (L.R.V.) Test
Locked rotor voltage (L.R.V.) is the actual voltage available
at the compressor under a stalled condition.

single Phase Connections

Disconnect power from unit. Using a voltmeter, attach one
lead of the meter to the run "R" terminal on the compressor
and the other lead to the common "C" terminal of the com-
pressor. Restore power to unit.
Determine L.R.V.
Start the compressor with the volt meter attached; then stop
the unit. Attempt to restart the compressor within a couple
of seconds and immediately read the voltage on the meter.
The compressor under these conditions will not start and will
usually kick out on overload within a few seconds since the
pressures in the system will not have had time to equalize.
Voltage should be at or above minimum voltage of 197 VAC,
as specified on the rating plate. If less than minimum, check
for cause of inadequate power supply; i.e., incorrect wire
size, loose electrical connections, etc.
Amperage (L.R.A.) Test
The running amperage of the compressor is the most impor-
tant of these readings. A running amperage higher than that
indicated in the performance data indicates that a problem
exists mechanically or electrically.
Single Phase Running and L.R.A. Test
NOTE: Consult the specification and performance section
for running amperage. The L.R.A. can also be found on the
rating plate.
Select the proper amperage scale and clamp the meter
probe around the wire to the "C" terminal of the compressor.
Turn on the unit and read the running amperage on the me-
ter. If the compressor does not start, the reading will indicate
the locked rotor amperage (L.R.A.).
Overloads
The compressor is equipped with an external or internal
overload which senses both motor amperage and winding
temperature. High motor temperature or amperage heats
the overload causing it to open, breaking the common circuit
within the compressor.
Heat generated within the compressor shell, usually due to
recycling of the motor, is slow to dissipate. It may take any-
where from a few minutes to several hours for the overload
to reset.

Checking the Overload

WARNING
ELECTRIC SHOCK HAZARD
Turn off electric power before service or
installation. Extreme care must be used, if it
becomes necessary to work on equipment
with power applied.
Failure to do so could result in serious injury or
death.
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