Precautions Concerning Piping Connection And Valve Operation - Mitsubishi Electric CITY MULTI PQHY-P200YHM-A Manuel D'installation

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 (turned clockwise
all the way).
2 Connect a charging hose to the service port on the low-pressure/
high-pressure refrigerant service valve, and extract the gas in the
pipe section 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> Refrigerant service valve
(Liquid side/brazed type for PQHY-P·Y(S)HM-A)
(High-pressure side/brazed type for PQRY-P·Y(S)HM-A)
<B> Refrigerant service valve
(Gas side/brazed type for PQHY-P·Y(S)HM-A)
(Low-pressure side/brazed type for PQRY-P·Y(S)HM-A)
Shaft
A
Service port
B
Cap
C
Pinched connecting pipe severing portion
D
Pinched connecting pipe brazing portion
E
Warning:
• The sections between the refrigerant service valves and the pinched
connecting pipes are fi lled with gas and refrigerant oil. Extract the gas
and refrigerant oil in the above-mentioned pipe section before heating
the brazed section to remove the refrigerant service valve pinched
connecting pipe.
- If the brazed section is heated without fi 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 temperature of the valve from exceeding 120 ˚C.
• Direct the fl ame away from the wiring and metal sheets inside the unit
to prevent heat damage.
Caution:
• Do not vent R410A into the atmosphere.
• R410A is a Fluorinated Greenhouse gas, covered by the Kyoto
Protocol, with a Global Warming Potential (GWP) = 1975.
• 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 is not touching other refrigerants pipes,
unit panels, or base plates.
Be sure to use non-oxidative brazing when connecting pipes.
Be careful not to burn the wiring and plate when brazing.
<Refrigerant piping connection examples>
[Fig.10.2.2] (P.8)
Connecting pipe (ID 19.05, ID 15.88) <Included with heat source unit>
1
Connecting pipe (ID 25.4, ID 19.05) <Included with heat source unit>
2
Connecting pipe (ID 25.4, ID 22.2) <Included with heat source unit>
3
Connecting pipe (ID 19.05, OD 25.4) <Included with heat source unit>
4
<A> Front pipe routing
<C> High-pressure side PQRY-
P·Y(S)HM-A (Liquid side PQHY-
P·Y(S)HM-A)
Shape
A
When not attaching a low-pressure twinning pipe
B
When attaching a low-pressure twinning pipe (PQRY-P·YSHM-A ONLY)
C
Refrigerant service valve piping
D
On-site piping (low-pressure connecting pipe)
E
F On-site piping (high-pressure connecting pipe)
Twinning kit (sold separately)
G
On-site piping (low-pressure connecting pipe: to BC controller)
H
On-site piping (low-pressure connecting pipe: to heat source unit)
I
75 mm (reference measurement)
J
ID ø25.4 side
K
Severing portion
L
*1 For the attachment of 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·YHM-A)
P200 : Expand the high-pressure side on-site piping
P250, P300 (ID9.52) and connect to the refrigerant service valve
piping.
P200
: Use the included connecting pipe 2, 4 to connect.
P250, P300
: Use the included connecting pipe 3 to connect.
• Pipe routing (for PQRY-P·YHM-A)
P200
: Use the included connecting pipe 1 to connect.
P250, P300 : Expand the high-pressure side on-site piping
(ID19.05) and connect to the refrigerant service
valve piping.
P200
: Use the included connecting pipe 2 to connect.
P250, P300
: Use the included connecting pipe 3 to connect.
Satisfy the minimum insertion depth in the table below when expanding on-site
piping
Pipe diameter (mm)
5 or more less than 8
8 or more less than 12
12 or more less than 16
16 or more less than 25
25 or more less than 35
35 or more less than 45
• After evacuation and refrigerant charging, ensure that the handle is fully
open. If operating with the valve closed, abnormal pressure will be imparted
to the high- or low-pressure side of the refrigerant circuit, giving damage to
the compressor, four-way valve, etc.
• Determine the amount of additional refrigerant charge by using the formula,
and charge refrigerant additionally through the service port after completing
piping connection work.
• After completing work, tighten the service port and cap securely so as not to
generate any gas leakage. (Refer to the table on the below for appropriate
tightening torque.)
<B> Low-pressure side PQRY-
P·Y(S)HM-A (Gas side PQHY-
P·Y(S)HM-A)
<D> Severing portion referral fi gure
Minimum insertion depth (mm)
6
7
8
10
12
14
23