Friedrich SH20J30B-A Air Conditioner User Manual


 
5
FAN MOTOR (Figure 4)
A 230 volt single phase permanent split capacitor
motor is used to drive the evaporator blower and
condenser fan. A running capacitor is wired
across the start and run terminals of the motor.
The motor is totally enclosed and is protected with
a line voltage overload located internally of the
motor. The motor shaft is stainless steel to resist
corrosion.
CHECKING COMPRESSOR EFFICIENCY
The reason for compressor inefficiency is
normally due to broken or damaged suction
and/or discharge valves, reducing the ability of
the compressor to pump refrigerant gas.
This condition can be checked as
follows:
1. Install a piercing valve on the suction and
discharge or liquid process tube.
2. Attach gages to the high and low sides of the
system.
3. Start the system and run a "cooling or
heating performance test."
If test shows:
A. Below normal high side pressure.
B. Above normal low side pressure.
C. Low temperature difference across the coil.
The compressor valves are faulty -
replace the compressor.
GROUND TEST
Use an ohmmeter set on its highest scale. Touch
one lead to the compressor body (clean point of
contact, as a good connection is a must) and the
other probe in turn to each compressor terminal.
(See Figure 3.) If a reading is obtained, the
compressor is grounded and must be replaced.
FIGURE 3 TYPICAL GROUND TEST
FAN MOTOR – TEST
Disconnect power to the unit.
1. Determine that the capacitor is serviceable.
2. Disconnect the black lead from the circuit
board.
3. Apply "live" test cord leads to the common
terminal of the capacitor and the black lead.
The motor should run at high speed.
FIGURE 4 FAN MOTOR