TM 9-4120-370-14
TO 35E9-229-1
5-12. CHARGING THE REFRIGERATION SYSTEM - Continued.
a.
Check that the hose from the low pressure service valve is connected to the compound gage side of the charg-
ing manifold, The hose from the high pressure service valve should be connected to the pressure gage side
of the charging manifold.
b.
Connect the center hose from the charging manifold to a well charged drum of refrigerant22.
Loosen the hose connections to the two air conditioner service valves slightly.
c.
Open the two charging manifold valves.
d.
e.
Open the refrigerant22 drum valve slightly to allow a small amount or refrigerant to purge air from the hoses.
Tighten the hose connections at the air conditioner service valves.
f.
Close the low pressure (suction) charging manifold valve. Never introduce liquid refrigerant into the low pres-
sure (suction) service valve.
Position the refrigerant22 drum so that liquid will be used for charging. (Some drums must be inverted and
g.
some are equipped with a selector valve.)
h.
Using accurate scales, measure and record the weight of the refrigerant22 drum.
CAUTION
These Air Conditioners are critical charge units. The scale used to weigh the re-
frigerant charge should have an accuracy of 0.2 pounds and should be periodi-
cally calibrated. When charging be sure that the total charge does not exceed 6.0
pounds.
i.
Open the refrigerant22 drum valve.
Open the high pressure service valve on the air conditioner. Allow liquid refrigerant to enter the system until
j.
the drum weight has decreased by 6.0 pounds (2.72 kg) or until system pressure has equalized.
k.
Close the refrigerant drum valve and the high pressure (discharge) manifold valve.
l.
Close high (discharge) pressure service valve.
m.
Connect power.
Press and release both pressure switch reset buttons.
n.
NOTE
If power has just been connected to unit, a short (30 minute maximum during very cold
weather) warm up period is required. When compressor reaches a safe operating tem-
perature, it will come on automatically if the mode selector switch is in the COOL mode.
Turn air conditioner on and operate in the COOL mode with the TEMPerature control thermostat set at a maxi-
o.
mum DECREASE position.
If the 6.0 pound (2.72 kg) full charge was obtained, skip steps q through s. If the system pressure equalized
p.
prior to obtaining a full charge of 6.0 pounds (2.72 kg) proceed with step q.
Switch the refrigerant drum to the gas only position.
q.
r.
Be sure that the refrigerant drum has been switched to the gas position and open the refrigerant drum valve,
the low (suction) pressure charging manifold valve, and the low (suction) pressure service valve on the air con-
ditioner.
Monitor the weight of the refrigerant drum as the air conditioner compressor pulls additional refrigerant gas into
s.
the system until the full 6.0 pound (2.72 kg) charge is obtained. When the system is fully charged, immediately
close the air conditioner low pressure service valve and refrigerant drum valve.
t.
Run the air conditioner in COOL mode (with Temperature control thermostat in full DECREASE position) for
15 minutes.
5-16