GMC 1976 ZEO 6083 Maintenance Manual page 752

CLEANING AIR CONDITIONER
For proper operation the unit should be clean.
Before any tests or repair work is started, check the
filter . The filter should be checked and cleaned regu
larly as use requires . If filter is dirty, wash in soapy
water and allow to dry. Do not use compressed air
to dry filter .
Next, open the shroud that covers the air condi-
The Mark IV and Duo-Therm units (figures 1
and 2) are mounted in similar manner. The inside
panel which includes the controls, the filter access,
and air directing vents, is bolted through the mount-
ing hole in the roof to the air conditioning unit
mounted outside to the roof of the vehicle.
For convenience and safety, it is best to remove
the unit from the roof of the vehicle to a shop bench
for tests or repair .
WARNING : USE CARE WHEN REMOVING AIR
CONDITIONING UNIT FROM ROOF OF VEHI-
CLE, TO AVOID FALL BY SERVICE PERSONNEL,
OR DROPPING UNIT .
REMOVAL
1 . Turn air conditioner off. Make sure that motor
generator and external power source are discon-
BREAKING INTO THE
REFRIGERATION SYSTEM (FIGURE
17)
1 . Clamp the tap valve on the process tube as
close as possible to the pinched end. Turn the valve
handle to puncture the line .
2 . Attach the gauge set suction valve to the tap
valve.
REPAIRING OR REPLACING
REFRIGERATION COMPONENTS
1 . When you locate a leak, shut off the refrigerant
and attach a discharge hose to the center manifold .
Route the hose into an exhaust hose or shop exhaust
system .
ROOF MOUNTED AIR CONDITIONER 24E- 1 3
tioner outside of the vehicle. If dirt, leaves, or other
material is lodged inside it will effect the operation
of the unit . Clean such debris away . Make sure noth-
ing is blocking the moving parts of the fan or blower .
If the air conditioner still does not operate prop-
erly, proceed with further tests.
AIR CONDITIONER REPLACEMENT
nected . Circuit breaker for air conditioner, located in
living area electrical compartment should be turned
off.
2. Remove bolts or nuts from inside panel.
Remove inside panel .
3. Disconnect vehicle air conditioning electrical
harness from air conditioner.
4. Disconnect bolts and nuts that secure unit to
roof of vehicle. Remove unit .
INSTALLATION
Reverse the removal procedure.
REFRIGERATION SYSTEM SERVICE
2 . Discharge the refrigerant slowly and watch
that the compressor oil doesn't come out with refrig-
erant. If you see oil, slow down the discharge rate .
3 . When the pressure is five pounds or less you
can open the system to repair it .
SOLDERING AND BRAZING
All connections are made by brazing. The parts
to be brazed, must be clean. Polish with a wire brush
or emery cloth until they shine.
The recommended material for connections is
Sil-Flos or equivalent . Use just enough heat so it will
melt and flow when touched to the metal.