Air Tight Test And Vacuum Drying - Daikin VRV IV-S Series Installation Manual

7-7 Air tight test and vacuum drying

After doing the piping, perform the following inspections.
Air tight test
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 is used, only pressurize to 450psi(3.1MPa) .
Vacuum drying
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
during the rainy season, if the actual work takes long enough that con-
densation 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.
Stop valve operation procedure
Precautions when handling the stop valve
• 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.
Servicing port
Valve stem
Valve cap
English
Flare nut
Field piping connection
• 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.
(Make sure that there is no gap)
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.
Direction to open
<Liquid pipe>
Precautions for handling valve cap
• A seal is attached to the point indicated by the arrow.
Take care not to damage it.
Valve cap
• Be sure to tighten the valve cap securely after operating the valves.
Liquid-side tightening torque
10.0 ~ 12.2 ft·lbf
13.5 ~ 16.5 N·m
Precautions for handling servicing port
• 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)
Silicon sealing pad
Direction to open
<Gas pipe>
Stop valve
(cap attachment)
Gas-side tightening torque
16.6 ~ 20.3 ft·lbf
22.5 ~ 27.5 N·m
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