Toshiba MMK-AP0072H, Service Manual

Page: 7 / 125

7
5. Recharge of Refrigerant
When recharge of the refrigerant is required, charge the new refrigerant with the specified amount in the
procedure as described below.
Q
Never charge the refrigerant over the specified amount.
R
Do not charge the additional refrigerant.
If charging refrigerant additionally when refrigerant gas
leaks, the refrigerant composition in the refrigerating
cycle changes resulted in change of air conditioner
characteristics or refrigerant over the specified stan-
dard amount is charged and an abnormal high
pressure is applied to the inside of the refrigerating
cycle resulted in cause of breakage or injury.
Q
Set the equipment so that liquid refrigerant can be charged.
R
When using a cylinder with siphon pipe, liquid can be charged without inversing the cylinder.
Gauge manifold
[ Cylinder with siphon ] [ Cylinder without siphon ]
OUTDOOR unit
Gauge manifold
OUTDOOR unit
Electronic
balance
Refriger ant
cylinder
Electronic
balance
Siphon
Refrigerant
cylinder
6. Environment
Use “Vacuum pump method” for an air purge (Discharge of air in the connecting pipe) in installation time.
• Do not discharge flon gas into the air to protect the earth environment.
• Using the vacuum pump method, clear the remained air (Nitrogen, etc.) in the unit. If the air remains, the
pressure in the refrigerating cycle becomes abnormally high and an injury and others are caused due to burst.
V
L
V
H
Connected to
indoor unit
Main
pipe
Valve fully closed
(gas side)
Center unit
Low-
pressure gauge
High-
pressure gauge
Gauge
manifold
Brazed
Service
port
Service port
Ø6.4
Copper pipe
Ø6.4
Copper pipe
Fully
tightened
Fully
tightened
Reducing
valve
Nitrogen
gas
Valve fully closed
(liquid side)
Valve fully closed
(balance)
Connected to other
terminal units
(Charge the refrigerant as below.)
Recover the refrigerant and check there is no refrigerant in the
equipment.
Leave it as it is for 1 to 2 minutes and check the indicator of
the compound gauge does not return.
Set the refrigerant cylinder on the electron balance, connect
the charge hose to connecting ports of the cylinder and the
electron gauge, and then charge the liquid refrigerant from the
service port at liquid side. (Shield with the gauge manifold so
that refrigerant does not flow to gas side.)
Connect the charge hose to the packed valve service ports at gas
side, liquid side, and balance side of the outdoor unit.
Open the packed valves of the balance pipe fully at liquid and gas
sides, and then return the valve at gas side a little to the closed side.
Open fully PMV of the outdoor unit.
• Turn on power of the outdoor unit.
• Short CN30 on I/F P.C. board of the outdoor unit.
• Turn off power of the outdoor unit within 2 minutes after short-circuiting.
Open fully the handle Low of the gauge manifold, and then turn on
the power of vacuum pump for vacuuming.
When the pressure has lowered until indication of the compound
gauge pointed -0.1MPa (-76cmHg), open fully the handle Low and
turn off the power of vacuum pump.
Connect the charge hose to vacuum pump adaptor.
R410A refrigerant is consisted with HFC mixed refrigerant.
Therefore if the refrigerant gas is charged, the composition
of the charged refrigerant changes and characteristics of
the equipment changes.
4mm-hexagonal wrench is required.
FILE NO. SVM-05052