506 01 2303 01 29
Specifications are subject to change without notice.
SER VICE
Refrigeration System
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in damage to
equipment .
This system uses R--410A refrigerant which has higher
pressures than R--22 and other refrigerants. No other
refrigerant may be used in this system. Gage set,
hoses, and recovery system must be designed to
handle R--410A. If you a re unsure consult the
equipment ma nufacturer.
CAUTION
!
Compressor Oil —
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in damage to
equipment .
The compressor in a R--410A system uses a polyolester
(POE) oil. This oil is extremely hygros copic, meaning it
abso r bs water readily. POE oils can absorb 15 times as
much water as other oils designed for HC F C and CFC
refrig er ants . Take all necessar y precaution s to avoid
exposure of the oil to the atmosphere.
CAUTION
!
Servicing Systems on Roofs with Synthetic Materials —
POE (polyolester) compre ssor lubricants a re known to
cause long term damage to some synthe tic roofing
materials. Exposure, even if immediately cleaned up, may
cause embrittlement (leading to cracking) to occur in one
year or more. When performing any service which may
risk exposure of compressor oil to the roof, ta ke
appropriate precautions to protect roofing. Procedures
which risk oil leakage include but are not limited to
compressor replacement, repairing refrigerants leaks,
replacing refrigerant components such as filter drier,
pressure switch, metering device, coil, accumulator, or
reversing valve.
Synthetic Roof Precautionary Procedure:
1. Cover extended roof working area with an imperme-
able pol yethylene (plastic) drop cloth or tarp. Cover
an approxi mate 10 x 10 ft (3.3 x 3.3 m) area.
2. Cover area in front of the unit service panel with a
terry cloth shop towel to absorb lubricant spills and
prevent run-offs, and protect drop cloth from tears
caused by t ools or components.
3. Place terry cloth shop towel inside unit immediately
under component(s) to be serviced and prevent lubri-
cant run-offs through the l ouvered openings in the
base pan.
4. Perform required service.
5. Remove and dispose of any oil contaminated mate rial
per loc al codes.
Liquid Line Filter Drier —
The factory-provided reversible filter drier is specifically
designed to operate with R-- 410A. Replace the filter drier
with factory-authorized components only with a filter
drier with desiccant made from 100% molecular sieve
grade XH-11. Filter drier must be replaced whenever the
refrigerant system i s opened.
When removing a filter drier, use a tubing cutter to cut the
drier from the system. Do not unsweat a filter drier from
the system. Heat from unsweating will release moisture
and contaminants from drier into system.
Field Refrigerant Access Ports —
Field service access to refrigerant pressures is through the
access ports located at the service valves (see Figs 28, 30
and 32). These ports are
-in SAE Flare couplings with
Schrader check valves and service caps. Use these ports to
admit nitrogen to the field tubing during brazing, to
evacuate the tubing and evaporator coil, to admit initial
refrigerant charge into the low-side of the system and
when checking and adjusting the system refrigerant
charge. When service activities are completed, ensure the
service caps are in place and secure; check for leaks. If
the Schrader check valve must be removed and
re-installed, tighten t o 2-3 in-lbs (23-34 N-cm).
Outdoor Coil Metering Devices —
The metering devices are multiple fixed–bore devices
(Acutrol) swaged into the horizont al outlet tubes from
the liquid header, located at the entrance to each outdoor
coil circuit path. These are non–adjustable. Service
requires replacing the entire liquid header assembly.
To check the outdoor coil, disconnect the outdoor fan
motor. Start the circuit in a Heating Mode (jumper R to
W1) and observe the frost pattern on the face of the
outdoor coi l. A frost pattern should develop uniformly
across the face of the outdoor coil starting at each tube at
the Acut rol nipple locations.
Failure to develop frost at an outlet tube ca n indicate a
plugged or a missing orifice.
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