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10.2. Precautions concerning piping
connection and valve operation
•
Conduct piping connection and valve operation accurately and carefully.
•
Removing the pinched connecting pipe
When shipped, a pinched connecting pipe is attached to the on site high-
pressure and low-pressure valves to prevent gas leakage.
Take the following steps 1 through 4 to remove the pinched connecting
pipe before connecting refrigerant pipes to the heat source unit.
1 Check that the refrigerant service valve is fully closed (clockwise).
2 Connect a charging hose to the service port on the low-pressure/
high-pressure refrigerant service valve, and extract the gas in the piping
between the refrigerant service valve and the pinched connecting pipe
(Tightening torque 12N·m).
3 After vacuuming gas from the pinched connecting pipe, sever the
pinched connecting pipe at the location shown in [Fig.10.2.1] and drain
the refrigerant.
4 After completing 2 and 3, heat the brazed section to remove the
pinched connecting pipe.
[Fig. 10.2.1] (P.8)
<A> Service valve for refrigerant
(Liquid side/brazed for PQHY-P·T(S)HMU-A/Y(S)HMU-A)
(High-pressure side/brazed for PQRY-P·T(S)HMU-A/Y(S)HMU-A)
<B> Service valve for refrigerant
(Gas side/brazed for PQHY-P·T(S)HMU-A/Y(S)HMU-A)
(Low-pressure side/brazed for PQRY-P·T(S)HMU-A/Y(S)HMU-A)
A
Shaft
B
Service port
C
Cap
D
Pinched connecting pipe severing portion
E
Pinched connecting pipe brazing portion
Warning:
•
The areas between the refrigerant service valves and the pinched
connecting pipes are ¿ lled with gas and refrigerant oil. Extract the gas
and refrigerant oil in that section before heating the brazed section.
- If the brazed section is heated without ¿ rst extracting the gas and
refrigerant oil, the pipe may burst or the pinched connecting pipe may blow
off and ignite the refrigerant oil, causing serious injury.
Caution:
•
Place a wet towel on the refrigerant service valve before heating the brazed
section to keep the valve temperature from exceeding 120 ÛC [248ÛF].
•
Direct the À ame away from the wiring and metal sheets inside the unit.
Caution:
•
Refrigerant pipe connection
This product includes connecting pipes for front piping. (Refer to [Fig.10.2.2])
Check the high-pressure/low-pressure piping dimensions before connecting
the refrigerant pipe.
Refer to item 9.2 Refrigerant piping system for piping dimensions.
Make sure that the refrigerant pipe does not touch other refrigerants pipes,
unit panels, or base plates.
Use non-oxidative brazing when connecting pipes.
Do not burn the wiring and plate when brazing.
22
<Example of refrigerant piping connection>
[Fig.10.2.2] (P.8)
1
Connecting pipe (ID 19.05 [3/4], ID 15.88 [5/8]) <Included with heat source
unit>
2
Connecting pipe (ID 25.4 [1], ID 19.05 [3/4]) <Included with heat source unit>
3
Connecting pipe (ID 25.4 [1], ID 22.2 [7/8]) <Included with heat source unit>
4
Connecting pipe (ID 19.05 [3/4], OD 25.4 [1]) <Included with heat source
unit>
<A> Front pipe routing
<C> High-pressure side PQRY-
P·T(S)HMU-A/Y(S)HMU-A
(Liquid side PQHY-P·T(S)HMU-A/
Y(S)HMU-A)
A
Shape
B
Without a low-pressure twinning pipe
C
With a low-pressure twinning pipe (PQRY-P·TSHMU-A/YSHMU-A ONLY)
D
Refrigerant service valve pipes
E
Field-supplied piping (low-pressure connecting pipe)
F
Field-supplied piping (high-pressure connecting pipe)
G
Twinning kit (sold separately)
H
Field-supplied piping (low-pressure connecting pipe: to BC controller)
I
Field-supplied piping (low-pressure connecting pipe: to heat source unit)
J
75 mm [2-31/32 in] (reference)
K
ID ø25.4 mm [1 in] side
L
Portion removed
*1 To attach the Twinning pipe (sold separately), refer to the
instructions included in the kit.
*2 Connection pipe is not used when the Twinning Kit is attached.
*3 Use a pipe cutter to sever.
•
Pipe routing (for PQHY-P·THMU-A/YHMU-A)
P72
: Expand the high-pressure side ¿ eld-supplied piping
P96, P120
(ID9.52 [3/8'']) and connect to the refrigerant service
valve piping.
: Use the included connecting pipe 2, 4 to connect.
P72
: Use the included connecting pipe 3 to connect.
P96, P120
•
Pipe routing (for PQRY-P·THMU-A/YHMU-A)
: Use the included connecting pipe 1 to connect.
P72
P96, P120
: Expand the high-pressure side ¿ eld-supplied piping
(ID19.05 [3/4'']) and connect to the refrigerant
service valve piping.
: Use the included connecting pipe 2 to connect.
P72
: Use the included connecting pipe 3 to connect.
P96, P120
Satisfy the minimum insertion depth in the table below when expanding ¿ eld-
supplied piping
Pipe diameter
(mm [in])
5 [7/32] or more, less than 8 [11/32]
8 [11/32] or more, less than 12 [1/2]
12 [1/2] or more, less than 16 [21/32]
16 [21/32] or more, less than 25 [1]
25 [1] or more, less than 35 [1-13/32]
35 [1-13/32] or more, less than 45 [1-25/32]
•
After evacuation and refrigerant charging, ensure that the handle is fully
open. If keep the valve closed, the high- or low-pressure side of the
refrigerant circuit may be subjected to abnormal pressure and may damage
the compressor, four-way valve, etc.
•
Determine the amount of additional refrigerant charge by using the formula,
and charge refrigerant through the service port after connecting the pipes.
•
Tighten the service port and cap securely so gas does not leak. (Refer to the
table below for appropriate tightening torque.)
<B> Low-pressure side PQRY-
P·T(S)HMU-A/Y(S)HMU-A
(Gas side PQHY-P·T(S)HMU-A/
Y(S)HMU-A)
<D> Severing portion referral ¿ gure
Minimum insertion depth
(mm [in])
6 [1/4]
7 [9/32]
8 [11/32]
10 [13/32]
12 [1/2]
14 [9/16]
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