Precautions in Servicing The Models with New-type Refrigerant Si33-105
246 Appendix R407C PLUS Series Heat Recovery System
4. Precautions in Servicing The Models with New-
type Refrigerant
Compared to the conventional refrigerant R22, the brand-new refrigerant R407C is higher in
pressure. The refrigerant oil is also different in type. With this in mind, note that the piping work
procedures as well as the related tools and piping materials are partially different than ever
before.
4.1 Tools Required
Some specific tools are required for servicing the refrigerant line of the new-type refrigerant
models. Select the right tools referring to the table below.
Typical tools and materials for piping works and their interchangeability
Refrigerant Conventional type New type
R22 (single) R407C (mixed)
Refrigerant oil Mineral oil (Suniso) Synthetic oil (ether)
Condensation pressure 1.84MPa 2.01MPa
Name Work process and application Interchangeability with conventional tools and materials
Pipe cutter Refrigerant piping
work
Cutting pipes Interchangeable.
Flaring tool Flaring pipes
Refrigerant oil Applying on flared spots Specified ether oil, ester oil, alkyl benzene oil or their
mixture to be used.
Torque wrench
Connecting flare nut
Interchangeable.
Pipe expander Expanding pipes at
connections
Pipe bender Bending pipes
Nitrogen Air-tightness test Inhibiting oxidation in
pipes
Welder Brazing pipes
Gauge manifold Air-tightness test
thru refrigerant
recharging
Vacuum refrigerant
charging and running
test
Specific tools required for boosting the pressure and
preventing impurities from coming in.
Charging hose
Vacuum pump Vacuum drying Interchangeable.
(Adapter to be connected to keep the oil from flowing
back to the unit during pump shut-down. Pump with anti-
backflow function also available.)
Charging cylinder Refrigerant recharging Conventional cylinder not allowed because of different
refrigerant properties. (Need to weigh with the scale.)
Refrigerant
charging scale
Interchangeable.
Gas leak detector Gas leak test Specific detector needed. (R134a-compatible detector
allowed.)
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