Mitsubishi Electric MXZ-2C20NAHZ4 Notice D'installation page 7

4. PURGING PROCEDURES, LEAK TEST, AND TEST RUN
4-1. PURGING PROCEDURES AND LEAK TEST
1) Remove service port cap of stop valve on the side of the outdoor unit gas pipe. (The
stop valves are fully closed and covered in caps in their initial state.)
2) Connect gauge manifold valve and vacuum pump to service port of stop valve on
the side of the outdoor unit gas pipe.
3) Run the vacuum pump. (Vacuumize for more than 15 minutes.)
4) Check the vacuum with gauge manifold valve, then close gauge manifold valve,
and stop the vacuum pump.
5) Leave as it is for one or two minutes. Make sure the pointer of gauge manifold valve
remains in the same position. Confirm that pressure gauge shows -14.7 psi [Gauge]
(-0.101 MPa).
6) Remove gauge manifold valve quickly from service port of stop valve.
7) After refrigerant pipes are connected and evacuated, fully open the valve stem of
all stop valves on both sides of gas pipe and liquid pipe by the hexagonal wrench.
If the valve stem hits the stopper, do not turn it any further. Operating without fully
opening lowers the performance and this causes trouble.
8) Refer to 1-2., and charge the prescribed amount of refrigerant if needed. Be sure
to charge slowly with liquid refrigerant. Otherwise, composition of the refrigerant in
the system may be changed and affect performance of the air conditioner.
9) Tighten cap of service port to obtain the initial status.
10) Leak test
WARNING
When opening or closing the valve
below freezing temperatures,
refrigerant may spurt out from the
gap between the valve stem and the
valve body, resulting in injuries.
4-2. GAS CHARGE
Perform gas charge to unit.
1) Connect gas cylinder to the service port of stop valve.
2) Perform air purge of the pipe (or hose) coming from refrigerant gas cylinder.
3) Replenish specified amount of the refrigerant, while operating the air conditioner for cooling.
Note:
In case of adding refrigerant, comply with the quantity specified for the refrigerating cycle.
When charging the refrigerant system with additional refrigerant, be sure to use liquid
refrigerant. Adding gas refrigerant may change the composition of the refrigerant in
the system and affect normal operation of the air conditioner. Also, charge the liquid
refrigerant slowly, otherwise the compressor will be locked.
To maintain the high pressure of the gas cylinder, warm the gas cylinder with warm
water (under 104°F (40°C)) during cold season. But never use naked fire or steam.
Valve body
Cap
Valve stem
CAUTION
Compound pressure
gauge (for R410A)
-14.7 psi
Pressure gauge
(-0.101 MPa)
(for R410A)
Handle Low
Handle High
Charge hose
Gauge manifold
(for R410A)
valve
(for R410A)
Vacuum pump
(for R410A)
Service port cap
(Torque 7 to 9 ft-lb,
10 to 12 N•m, 100
to 120 kgf•cm)
Precautions when us-
ing the control valve
A
Control
valve
Open
Service port
Close
Charge hose
Body (for R410A)
Model
MXZ-2C
MXZ-3C
MXZ-5C
Union
Union
Union
Union
Refrigerant gas
cylinder
operating valve
(for R410A)
Refrigerant gas cylinder for R410A with siphon
Refrigerant (liquid)
Valve stem
Close
Open
Hexagonal wrench
Stop valve cap
(Torque 15 to
20 ft-lb, 21.5 to
27.5 N•m, 220
to 280 kgf•cm)
Stop valve cap
(Torque 18 to
22 ft-lb, 24.4 to
30.4 N•m, 250
to 310 kgf•cm)
When attaching the control valve
to the service port, valve core may
deform or loosen if excess pres-
sure is applied. This may cause
gas leak.
When attaching the control valve to
the service port, make sure that the
valve core is in closed position, and
then tighten part A. Do not tighten
part A or turn the body when valve
core is in open position.
Indoor unit
A – B
A – C
A – E
Stop valve
Liquid
pipe
Indoor
Outdoor
unit
unit
Stop valve with
Gas
service port
pipe
Gauge manifold
valve (for R410A)
Charge hose
(for R410A)
Electronic scale for refrigerant charging
en
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