Thermo King KD-II SR, Manual

Page: 64 / 182

Electrical Maintenance (Rev. 04/03)
50
5. If the switch is out of calibration, pressurize the hose
again until the tester indicates 0.7 in. (17.78 mm) H
2
O.
Adjust the screw clockwise or counterclockwise until
the switch closes and the continuity tester indicates a
completed circuit with the gauge reading 0.7 in. (17.78
mm) H
2
O. Release the pressure.
6. Repeat test procedure several times to be sure the set-
ting is correct.
7. Remove the test equipment. Install wire on switch ter-
minal and air sensing tubes on air switch. The BLACK
hose from the high pressure or air inlet side of the evap-
orator coil goes on the hose fitting on the side of the air
switch stamped BLACK. The CLEAR hose from the
low pressure or air outlet side of the evaporator coil
goes on the hose fitting on the side of the air switch
stamped CLEAR.
NOTE: Route hoses for continuous slope to avoid conden-
sate traps.
If too much frost continues to accumulate before defrost,
decrease the pressure setting. Turn the adjustment screw
counterclockwise.
If defrost action occurs with too little frost accumulation,
increase the pressure setting. Turn the adjustment screw
clockwise.
1. Tool No. 204-442
2. Squeeze Bulb Tool No. 204-494
3. Continuity Test
Testing Air Switch