898150-UIM-B-0113
Johnson Controls Unitary Products
19
LEAK TEST AND EVACUATION
Air and moisture remaining in the refrigerant system will have undesir-
able effects as indicated below:
1. Pressure in the system rises.
2. Operating current rises.
3. Cooling or heating efficiency drops.
4. Moisture in the refrigerant circuit may freeze and block capillary
tubing (30 kBtu size only).
5. Water may lead to corrosion of parts in the refrigeration system.
The line set between the indoor and outdoor units must be leak tested
and evacuated to remove any non-condensable and moisture from the
system.
AIR PURGING WITH VACCUM PUMP
Be sure to use a vacuum pump with counter-flow prevention function to
make oil inside the pump does not flow back into the system pipes
when the pump stops.
1. Unscrew and remove the caps from the 2-way and 3-way valves.
2. Unscrew and remove the cap from the service valve.
3. Connect the vacuum pump hose to the service valve.
4. Operate the vacuum pump for 10-15 minutes until an absolute vac-
uum of 300 microns has been reached.
5. With the vacuum pump still in operation, close the low-pressure
knob on the vacuum pump coupling. Stop the vacuum pump.
6. Open the 2-way valve by a 1/4 turn and then close it after 10 sec-
onds. Check all the joints for leaks using liquid soap or an electronic
leak device.
7. Turn the body of the 2-way and 3-way valves. Disconnect the vac-
uum pump hose.
8. Replace and tighten all the caps on the valves.
ADDING REFRIGERANT FOR LONGER LINE SET
1. Open the low side manifold gauge valve and weigh in liquid refriger-
ant. Use Table 6 to calculate the correct weigh-in charge.
2. Close manifold gauge valves.
Action
Shut-off
2-way Valve
Suction/Vapor
2-way Service Valve
Evacuating with a
vacuum pump
Outdoor unit running
Checking pressure
and adding refrigerant
FIGURE 40:
Service Valve Operation
SUCTION/VAPOR
2-WAY SERVICE VALVE
HOSE WITH
SCHRADER VALVE
PUSH
REQUIRES FIELD PROVIDED 5/16” FEMALE
FLARE TO 1/4” MALE FLAREADAPTER.
VALVE CAP
OPEN POSITION
CLOSED POSITION
SCHRADER CORE
FLARE CAP
TO LINE SET
SERVICE
PORT CAP
SERVICE
PORT
TO OUTDOOR UNIT
FLARE CAP
ALLEN WRENCH (5MM)
OPEN POSITION
CLOSED POISTION
TO OUTDOOR UNIT
TO LINE SET
CLOSED
FULLY
OPEN
FULLY
OPEN
FIGURE 41:
Air Purging Procedure
FIGURE 42:
Gauge Set Connections for Test Leaks, Evacuation
Charging
VACUUM
PUMP
VACUUM
PUMP
VACUUM
PUMP
COMPOUND
PRESSURE
GAUGE
PRESSURE GAUGE
-101kPa
(-76cmHg)
HANDLE LOW
MANIFOLD VALVE
HANDLE HIGH
(KEEP FULL
CLOSED)
CHARGE HOSE
CHARGE HOSE
CONNECTING
PIPE
PACKED VALVE
AT LIQUID SIDE
VACUUM PUMP
ADAPTER FOR
COUNTER-FLOW
PREVENTION
PACKED VALVE AT GAS SIDE
SERVICE PORT
SCHRADER CORE
VACUUM
PUMP
