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Fig. 26—Defrost Thermostat
C99029
FEEDER TUBE
STUB TUBE
DEFROST
THERMOSTAT
HEAT PUMP WITH PURON—QUICK REFERENCE GUIDE
Puron refrigerant operates at 50-70 percent higher pressures than R-22. Be sure that servicing equipment and replacement components are
designed to operate with Puron. Puron refrigerant cylinders are rose colored.
• Puron refrigerant cylinders manufactured prior to March 1, 1999, have a dip tube that allows liquid to flow out of cylinder in upright position.
Cylinders manufactured March 1, 1999 and later DO NOT have a dip tube and MUST be positioned upside down to allow liquid to flow.
• Recovery cylinder service pressure rating must be 400 psig (2758 kpa). DOT 4BA400 or DOT BW400.
• Puron systems should be charged with liquid refrigerant. Use a commercial type metering device in the manifold hose.
• Manifold sets should be 750 psig (5171 kpa) high-side and 200 psig (1379 kpa) low-side with 520 psig (3585 kpa) low-side retard.
• Use hoses with 750 psig (5171 kpa) service pressure rating.
• Leak detectors should be designed to detect HFC refrigerant.
• Puron, as with other HFCs, is only compatible with POE oils.
• Vacuum pumps will not remove moisture from oil.
• Only use factory specified liquid-line filter driers with rated working pressures no less than 600 psig (4137 kpa).
• Do not install a suction-line filter drier in liquid line.
• POE oils absorb moisture rapidly. Do not expose oil to atmosphere.
• POE oils may cause damage to certain plastics and roofing materials.
• Wrap all filter driers and service valves with wet cloth when brazing.
• A Puron liquid-line filter drier is required on every unit.
• Do not use an R-22 TXV.
•
Never
open system to atmosphere while it is under a vacuum.
• When system must be opened for service, break vacuum with dry nitrogen and replace filter driers.
• Do not vent Puron into the atmosphere.
• Observe all
warnings, cautions,
and
bold
text.
• Do not leave Puron suction line driers in place for more than 72 hrs.
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