12
English
7-8 Air tight test and vacuum drying
After doing the piping, perform the following inspections.
Be sure to use nitrogen gas. (See the figure (“Stop valve operation pro-
cedure”) for the location of the service port.)
[Procedure]
Pressurize from the liquid pipes and gas pipes to 550psi(3.8MPa) (and
not above 550psi(3.8MPa)). If there is not pressure drop over the next
24 hours, the equipment has passed the test.
If the pressure drops, check for leakage positions. (Confirm that there is
no leakage, then release nitrogen.)
If a FXTQ indoor unit and a CXTQ unit are used, only pressurize to
450psi(3.1MPa).
Use a vacuum pump that can create a vacuum down to at least
500 microns
.
[Procedure]
Operate the vacuum pump for
at least 2 hours
from
both the liquid and
gas pipes
and decrease the pressure to at least 500 microns.
Leave at below 500 microns for at least 1 hour and make sure that the
vacuum gauge does not rise. (If it does rise, there is either still moisture
in the system or a leak.)
Cases where moisture might enter the piping
(i.e., if doing work dur-
ing the rainy season, if the actual work takes long enough that conden-
sation may form on the inside of the pipes, if rain might enter the pipes
during work, etc.)
After performing the vacuum drying for 2 hours, pressurize to
7.2psi(0.05MPa) (i.e., vacuum breakdown) with nitrogen gas, then
depressurize down to at least 500 microns a for an hour using the vac-
uum pump (vacuum drying). (If the pressure does not reach at least 500
microns even after depressurizing for at least 2 hours, repeat the vacuum
breakdown - vacuum drying process.) Leave as a vacuum for 1 hour after
that, and make sure the vacuum gauge does not rise.
(Refer to figure 27)
1.
Decompression valve
2.
Nitrogen
3.
Vacuum pump
4.
Valve (Open)
5.
Charge hose
6.
Stop valve service port
7.
Indoor unit
8.
Gas line stop valve (Close)
9.
Liquid line stop valve (Close)
10.
Indicates local procurement
11.
Outdoor unit
NOTE
The stop valve must always be turned to “closed”.
Otherwise the refrigerant in the outdoor unit will pour out.
• The names of parts needed to operate the stop valve are shown in
the figure below. The unit is shipped from the factory with the stop
valve turned to the “closed” position.
• Since the side boards may be deformed if only a torque wrench is
used when loosening or tightening flare nuts, always lock the stop
valve with a wrench and then use a torque wrench.
• In cases where the unit is run in heating mode when the outside tem-
perature is low or in other situations where the operating pressure
might drop, seal the gas-side flare nut on the stop valve with silicon
sealant or the like to prevent it from freezing.
Stop valve operation procedure
Have a hex wrench ready (size: 0.2in.(4mm) and 0.3in.(6mm)).
Opening the valve
1.
Place the hex wrench on the valve stem and turn counter-clockwise.
2.
Stop when the valve stem no longer turns. It is now open.
Close the valve
1.
Place the hex wrench on the valve stem and turn clockwise.
2.
Stop when the valve stem no longer turns. It is now closed.
• A seal is attached to the point indicated by the arrow.
Take care not to damage it.
• Be sure to tighten the valve cap securely after operating the valves.
• Use a push-rod-provided charging hose for operation.
• Be sure to tighten the valve cap securely after operation.
Tightening torque ................. 8.5 ~ 10.3 ft·lbf (10.8 ~ 14.7 N·m)
Air tight test
Vacuum drying
Stop valve operation procedure
Precautions when handling the stop valve
Servicing port
Valve stem
Flare nut
Valve cap
Field piping connection
Precautions for handling valve cap
Liquid-side tightening torque
Gas-side tightening torque
10.0 ~ 12.2 ft·lbf
13.5 ~ 16.5 N·m
16.6 ~ 20.3 ft·lbf
22.5 ~ 27.5 N·m
Precautions for handling servicing port
Silicon sealing pad
(Make sure that there is no gap)
Direction to open
Direction to open
<Gas pipe>
<Liquid pipe>
Valve cap
Stop valve
(cap attachment)
01_EN_3P591321-3B.fm Page 12 Tuesday, December 24, 2019 10:28 AM
