Mitsubishi Heavy Industries SRK20ZG-S Tech Manual page 33

(3) Air purge
(a) Tighten all flare nuts in the pipings both indoor and outside will so as not to cause leak.
(b) Connect service valve, charge hose, manifold valve and vacuum pump as is illustrated below.
(c) Open manifold valve handle Lo to its full width, and perform vacuum or evacuation.
Continue the vacuum or evacuation operation for 15 minutes or more and check to see that the vacuum gauge reads – 0.1 MPa
(– 76 cmHg).
(d) After completing vacuum operation, fully open service valve (Both gas and liquid sides) with hexagon headed wrench.
(e) Detach the charge hoses.
(f) Check for possible leakage of gas in the connection parts of both indoor and outdoor.
¡ Since the system uses service ports differing in diameter from those found on the conventional models, a charge hose (for R22)
presently in use is not applicable.
Please use one designed specifically for R410A
¡ Please use an anti-reverse flow type vacuum pump adapter so as to prevent vacuum pump oil from running back into the system.
Oil running back into an air-conditioning system may cause the refrigerant cycle to break down.
Additional refrigerant charge
¡ 20, 25, 35 type
Additional refrigerant charge is not required at all.
¡ 50 type
When refrigerant piping exceeds 15m conduct additional refrigerant charge by weight after refrigerant piping completion.
Additional charge amount per meter = 20g/m
[Example]
How much amount of additional charge for 25m piping?
(25 – 15)m × 20g/m = 200g 200g for additional charge
(4) Insulation of connecting portion
(a) Cover the connecting portion of the refrigerant piping with the pipe cover and seal them.
If neglecting to do so, moisture occurs on the piping and water will drip out.
Vinyl tape
(b) Finishing and fixing
1) Tie up the piping with wrapping tape, and shape it so
that it conforms to which the pipe is attached.
2) Fix them with clamps as right figure.
Service Valve
(two-way valve)
–0.1MPa
(–76cmHg)
Service Valve
(three-way valve)
Handle Lo
Service Port
Charge hose
(Designed specifically for R410A)
To cover the connecting portion with
insulation material materials, cut upper portion
and then seal it with insulation materials.
-
Compound
Pressure
pressure
gauge
gauge
Gauge Manifold
(Designed specifically for R410A)
Handle Hi.
Charge hose
(Designed specifically for R410A)
Vacuum pump
Vacuum pump adapter
(Anti-reverse flow type)
(Designed specifically for R410A)
Insulation
Refrigerant piping
Electrical wiring
Covering tape
Drain hose
Tapping screw
30
-
Cover the exterior portion with cov-
ering tape and shape the piping so
it will match the contours of the
route that the piping to take. Also
fix the wiring and pipings to the
wall with clamps.