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Caution:
•
Use a vacuum pump with a reverse flow check valve.
- If the vacuum pump does not have a reverse flow check valve, the vacuum
pump oil may flow back into the refrigerant cycle and cause deterioration of
the refrigerant oil.
•
Do not use the tools shown below used with conventional refrigerant.
(Gauge manifold, charge hose, gas leak detector, check valve,
refrigerant charge base, vacuum gauge, refrigerant recovery
equipment)
- Mixing of conventional refrigerant and refrigerant oil may cause the
refrigerant oil to deteriorate.
- Mixing of water will cause the refrigerant oil to deteriorate.
- R410A refrigerant does not contain any chlorine. Therefore, gas leak
detectors for conventional refrigerants will not react to it.
•
Manage tools used for R410A carefully.
- If dust, dirt, or water gets in the refrigerant cycle, the refrigerant oil will
deteriorate.
•
Never use existing refrigerant piping.
- The large amount of chlorine in conventional refrigerant and refrigerant oil
in existing piping will cause the new refrigerant to deteriorate.
•
Store the piping to be used during installation indoors and keep both
ends of the piping sealed until just before brazing.
- If dust, dirt, or water get into the refrigerant cycle, the oil will deteriorate
and the compressor may fail.
•
Do not use a charging cylinder.
- Using a charging cylinder may cause the refrigerant to deteriorate.
•
Do not use special detergents to wash the piping.
9.. Refrigerant piping system
Example of refrigerant piping system
[Fig. 9..1] (P.4)
Heat source model
Gas side
Liquid pipe
Model number
The first branch of P144 ~ P240
Joint
4-Branch header (Downstream indoor unit model total <= 72)
8-Branch header (Downstream indoor unit model total <= 144)
10-Branch header (Downstream indoor unit model total <= 240)
Heat source twinning kit
A Heat source unit
C Indoor unit
E Heat source twinning kit
*1 ø12.7 for over 90 m [295-1/4in]
*2 ø12.7 for over 40 m [131-3/16in]
*3 The pipe sizes listed in columns A1 to A3 in this table correspond to the sizes
for the models listed in the unit 1, 2, and 3 columns. When the order of the
models for unit 1, 2, and 3 change, make sure to use the appropriate pipe size.
*4 B If the piping length after the first joint exceeds 40 m (≤ 90 m), use the one
size larger liquid pipe for the indoor unit. (for PQHY-P·Z(S)KMU-A)
*5 C When the height difference between the indoor units is 15 m or greater
(≤ 30 m), use the one size larger liquid pipe for the indoor unit (lower side). (for
PQHY-P·Z(S)KMU-A)
[Fig. 9..] (P.)
Heat source model
Low-pressure side
Liquid pipe
Model number
Heat source twinning kit
Low-pressure gas pipe
A Heat source unit
C BC controller (main)
E Indoor unit (06 ~ 54)
G Heat source twinning kit
*1 The pipe sizes listed in columns A1 to A2 in this table correspond to the sizes
for the models listed in the unit 1 and 2 columns. When the order of unit 1 and
2 is changed, make sure to use the appropriate pipe size for the model.
Precautions for heat source unit combinations
Refer to [Fig. 9.2.3] for the positioning of twinning pipes.
[Fig. 9..] (P.7)
<A> When the piping (from the twinning pipe) exceeds 2 m [6 ft], include a trap
(gas pipe only) within 2 m [6 ft]. Make sure the height of the trap is 200 mm
[7-7/8 in] or more.
If there is no trap, oil can accumulate inside the pipe, causing a shortage of
oil damaging the compressor. (for PQHY-P·ZSKMU-A)
<B> Example of piping connection (for PQHY-P·ZSKMU-A)
Indoor unit
A
Within 2 m [6 ft]
C
Field-supplied piping
E
Straight pipe length that is 500 mm [19-11/16 in] or more
G
Liquid side
Total capacity of indoor units
Gas pipe
Downstream unit model total
The first branch of P264 ~ P360
B 1st branch
D Cap
F Header
High-pressure side
Total capacity of indoor units
Gas pipe
Downstream unit model total
High-pressure gas pipe
B BC controller (standard)
D BC controller (sub)
F Indoor unit (72 ~ 96)
Trap (gas pipe only)
B
Twinning pipe
D
Twinning kit
F
Precautions for heat source unit combinations
Refer to [Fig. 9.2.4] for the positioning of twinning pipes.
[Fig. 9..4] (P.7)
<A> Install the piping so that oil will not accumulate in the stopped heat source
unit. (both the liquid and the gas side for PQHY-P·ZSKMU-A, the high-
pressure side only for PQRY-P·ZSKMU-A)
1.
The NG example shows that oil accumulates because the units are installed
on a reverse gradient while unit 1 is in operation, and unit 3 is stopped.
2.
The NG example shows that oil accumulates into units 1 and 2 while unit 3
is in operation, and units 1 and 2 are stopped. Vertical pipe height (h) should
be 0.2 m (7-7/8 in) or below.
3.
The NG example shows that oil accumulates into unit 1 while unit 3 is in
operation, and unit 1 is stopped. Vertical pipe height (h) should be 0.2 m
(7-7/8 in) or below.
4.
The NG example shows that oil accumulates into unit 3 while unit 1 is in
operation, and unit 3 is stopped. Vertical pipe height (h) should be 0.2 m
(7-7/8 in) or below.
<B> Slope of twinning pipes (for PQHY-P·ZSKMU-A)
Make sure the slope of the twinning pipes are at an angle within ±15° to the
horizontal plane.
If the slope exceeds the angle specified, the unit may be damaged.
<C> Example of piping connection (for PQRY-P·ZSKMU-A)
Slope downward
A
BC controller (standard or main)
C
Slope of the twinning pipe is at an angle within ±15° to the ground
E
Twinning pipe (low-pressure side)
F
Field-supplied piping (low-pressure connecting pipe: between heat source
H
units)
Field-supplied piping (low-pressure main pipe: to BC controller)
I
Field-supplied piping (high-pressure main pipe: to BC controller)
J
Caution:
•
Do not install traps to prevent oil backflow and compressor start-up
failure.
•
Do not install solenoid valves to prevent oil backflow and compressor
start-up failure.
•
Do not install a sight glass because it may show improper refrigerant
flow.
If a sight glass is installed, inexperienced technicians that use the
glass may overcharge the refrigerant.
Slope upward
B
Twinning pipe
D
Twinning pipe (high-pressure side)
G
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