6
Fig. 6
Fig. 7
Thermal insulation
(120°C or higher heat
resistance)
Duct (or similar) tape
for waterproofing
Thermal insulation
Liquid tube
(Narrow tube)
Control cable
Gas tube
(Wide tube)
5. Tubing airtightness test and vacuum application
An airtightness test is required for gas heat pump A/C as part of industry installation guidelines. Follow the
procedure below to perform the test and confirm there is no leakage from any connections.
Connect the manifold gauge to both service ports - on the wide tube side and narrow tube side. Then connect the
nitrogen tank, vacuum pump, and other items as shown in Fig. 6.
Use nitrogen to raise the pressure to the airtightness test pressure (4.15
MPa) and confirm that there is no leakage. Refrigerant leakage can cause
suffocation and injury to nearby persons.
Manifold gauge
Pressure gauge
Pressure reducing value
Value
Vacuum pump
Vacuum
gauge
Weight scale
(Outdoor unit)
Close value
(Water heat exchanger unit)
After the airtightness test is completed, apply vacuum of 667 Pa or below to the water heat exchanger unit and
tubing.
Do not leave for a long period of time after the vacuum state has been reached.
6. Charge additional refrigerant. (See Table 1, Table 2, figure 6)
For details, refer to the "To Those Undertaking the Trial Operation."
7. Thermally insulate the pipes.
Thermally insulate the pipes only after checking for leaks at the pipe connection area.
Thermal insulation must be performed on both thick and thin pipes.
