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APPENDIX A — AIR CONDITIONER AND HEAT PUMP WITH PURON
®
—
QUICK REFERENCE GUIDE
• Puron (R-410A) refrigerant operates at 50 percent to 70
percent higher pressures than R-22. Be sure that servicing
equipment and replacement components are designed to
operate with Puron refrigerant.
• Puron refrigerant cylinders are rose colored.
• Recovery cylinder service pressure rating must be
400 psig, DOT 4BA400 or DOT BW400.
• Puron systems should be charged with liquid refrigerant.
Use a commercial type metering device in the manifold
hose when charging into suction line with compressor op-
erating.
• Manifold sets should be 700 psig high side and 180 psig
low side with 550 psig low-side retard.
• Use hoses with 700 psig 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.
• Use only factory specified liquid-line filter driers with rat-
ed working pressures greater than 600 psig.
• 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 factory approved, liquid-line filter drier is required on
every unit.
• Do not use an R-22 TXV.
• If indoor unit is equipped with a TXV, it must be changed
to a Puron TXV.
• Never open system to atmosphere while it is under a vacuum.
• When system must be opened for service, recover refriger-
ant, break vacuum with dry nitrogen before opening
system.
• Always replace filter drier after opening system for
service.
• Do not vent Puron refrigerant into the atmosphere.
• Do not use capillary tube coils.
• Observe all warnings, cautions, and bold text.
• All Puron heat pumps must have indoor TXV.
• Do not leave Puron suction line driers in place for more
than 72 hours.
UNIT OPERATES TOO LONG OR CONTINUOUSLY
1. Low refrigerant charge. 1. Add refrigerant.
2. Control contacts fused. 2. Replace control.
3. Air in system. 3. Purge and evacuate system.
4. Partially plugged expansion valve or filter drier. 4. Clean or replace.
SYSTEM IS NOISY
1. Piping vibration. 1. Support piping as required.
2. Compressor noisy. 2. Replace compressor if bearings are worn.
COMPRESSOR LOSES OIL
1. Leak in system. 1. Repair leak.
2. Crankcase heaters not energized during shutdown. 2. Check wiring and relays. Check heater and replace if defective.
3. Improper interconnecting piping design. 3. Check piping for oil return. Replace if necessary.
FROSTED SUCTION LINE
1. Expansion valve admitting excess refrigerant. 1. Adjust expansion valve.
HOT LIQUID LINE
1. Shortage of refrigerant due to leak. 1. Repair leak and recharge.
2. Expansion valve opens too wide. 2. Adjust expansion valve.
FROSTED LIQUID LINE
1. Restricted filter drier. 1. Remove restriction or replace.
2. Liquid line solenoid valve partially closed. 2. Replace valve.
a. On 38AUD 16/25/28 systems, Outdoor Fans 2 and 4 will be off in cooling mode below 55°F ±1.5°F outdoor temperature.
Table 22 — Troubleshooting (cont)
PROBLEM SOLUTION
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