Daikin REYQ96MTJU, Инструкция по проектированию, установке и испытаниям, Страница: 38 / 236

Installation Si39-406
32 General Information
Heat Recovery
Series
„
Suction, Discharge Gas piping, liquid piping must be insulated.
„
Example of thermal insulation work.
„
If you think the humidity around the cooling piping might exceed 86°F and RH80%, reinforce the
insulation on the cooling piping (at least 13/16" thick). Condensation might from on the surface
of the insulation.
3.2.5 Air Tight Test
„
Operational steps
Essential Points
of Testing
(Maintaining
Pressure Over a
Period) The key to successful testing is strict adherence to the following procedure:
a) The liquid and gas piping in each refrigerant system should be pressurized in turn in accordance
with the following steps. (Nitrogen gas must be used.)
∗
Increasing the system pressure to 551psi does not guarantee the identification of minor leaks if
pressure is maintained for only a short time. It is therefore recommended that the system remain
pressurized in accordance with Step 3 above for at least 24 hours.
Note: The pressure must on no account be increased beyond 551psi.
b) Check for pressure drop
If there is no drop in pressure then the test is deemed a success.
If the pressure drops then the leak must be located. See following page.
However, if there is a change in the ambient temperature between the pressurizing stage and
the time when you check for a drop in pressure then you will have to adjust your calculations
accordingly since a change of 1°F can account for a pressure change of approximately 0.80psi.
Compensating adjustment value:
(temperature at time of pressurizing – temperature at time of checking) × 0.80
Example:
Time of pressurizing: 551psi 77°F
„
3 piping section (between outdoor unit and BS unit)
„
2 piping section (between BS unit and indoor unit)
Complete
refrigerant pipe
installation work
Pressurize Check for pressure drop Success
Locate and repair leaks
(V0987)
„
Step 1: increase pressure to 13.05psi for 3
minutes or more










Indicates existence of major leaks
„
Step 2: increase pressure to 217psi for 5
minutes or more
Indicates existence of minor leaks
„
Step 3: increase pressure to 551psi for
approx. 24 hours