Thermo King KD-II SR, Manual

Page: 63 / 182

Electrical Maintenance (Rev. 04/03)
49
With an external ammeter connected in series, a shorted
glow plug will show excessive current flow (more than
12 amps) when the PREHEAT switch is pressed or when
CB1 circuit breaker is tripped, check each plug.
CONDENSER/EVAPORATOR FAN
ROTATION (Electric Standby Operation)
The condenser and evaporator fans are belt driven. On elec-
tric standby operation, check for correct fan rotation by
placing a small cloth or sheet of paper against the condenser
fan grille on the front of the unit. Correct rotation will hold
the cloth or paper against the grille. Improper rotation will
blow the cloth or paper away from the grille. To correct
improper condenser fan rotation, reverse any two power
cord leads at the power cord. (DO NOT move the ground
wire which is normally GREEN.)
1. Ohmmeter
2. 1.5 Ohms
3. Remove Bar
Checking Glow Plugs
Defrost Air Switch Checkout and
Adjustment
Before testing or adjusting the air switch, check the clear
plastic tubing and black plastic tubing to the evaporator coil.
Make sure they are not obstructed or crushed. Check the
probes in the evaporator housing to be sure they are in
proper position, and make sure they are not obstructed.
1. Remove plastic sensing tubing from both sides of the
defrost air switch.
2. Disconnect one wire at switch terminal. Connect test
light or continuity tester to the two terminals used on
the switch.
3. Install test equipment (TK 204-442 and TK 204-494)
onto the hose fitting on the side of the air switch
stamped BLACK.
4. Pressurize the hose until the continuity tester indicates
a completed circuit. Now read the dial of the test gauge.
This is the setpoint of the air switch (correct reading is
0.7 ± 0.05 in. [17.78 ± 1.27 mm] H
2
O). Release the
pressure.
1. Adjustment Screw
Air Switch