Carrier 38AU - Manual (Page 27)

27
SERVICE
Refrigeration System
Compressor Oil —
Servicing Systems on Roofs With Synthetic
Materials — POE (polyolester) compressor lubricants are
known to cause long term damage to some synthetic 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 expo-
sure of compressor oil to the roof, take appropriate precautions
to protect roofing. Procedures which risk oil leakage include
but are not limited to compressor replacement, repairing refrig-
erants 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 impermeable
polyethylene (plastic) drop cloth or tarp. Cover an ap-
proximate 3.3 x 3.3 m (10 x 10 ft) 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 tools
or components.
3. Place terry cloth shop towel inside unit immediately un-
der component(s) to be serviced and prevent lubricant
run-offs through the louvered openings in the base pan.
4. Perform required service.
5. Remove and dispose of any oil contaminated material per
local codes.
Liquid Line Filter Drier — The factory-provided filter
drier is specifically designed to operate with Puron®. 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 refrig-
erant system is 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 sys-
tem. Heat from unsweating will release moisture and contami-
nants 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 27 and 29). These ports
are ¼-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
to 23-34 N-cm (2-3 in-lbs).
Factory High-Flow Access Ports — There are two
additional access ports in the system - on the suction tube
between the compressor and the suction service valve and on
the liquid tube near the liquid service valve (see Figs 28 and
30). These are brass fittings with black plastic caps. The hose
connection fittings are standard ¼-in SAE Male Flare
couplings.
The brass fittings are two-piece High Flow valves, with a re-
ceptacle base brazed to the tubing and an integral spring-closed
check valve core screwed into the base. (See Fig. 25) This
check valve is permanently assembled into this core body and
cannot be serviced separately; replace the entire core body if
necessary. Service tools are available from RCD that allow the
replacement of the check valve core without having to recover
the entire system refrigerant charge. Apply compressor refrig-
erant oil to the check valve core's bottom o-ring. Install the fit-
ting body with 1085 ±23 N-cm (96 ±-10 in-lbs) of torque; do
not overtighten.
Fig. 25 — CoreMax Access Port Assembly
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in damage to
equipment.
This system uses Puron® refrigerant which has higher
pressures than R-22 and other refrigerants. No other refrig-
erant may be used in this system. Gage set, hoses, and re-
covery system must be designed to handle Puron®. If you
are unsure consult the equipment manufacturer.
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in damage to
equipment.
The compressor in a Puron system uses a polyolester
(POE) oil. This oil is extremely hygroscopic, meaning it
absorbs water readily. POE oils can absorb 15 times as
much water as other oils designed for HCFC and CFC re-
frigerants. Take all necessary precautions to avoid exposure
of the oil to the atmosphere.
1/2-20 UNF RH
30°
0.596
.47 5/8” HEX
SEAT CORE
WASHER
DEPRESSOR PER ARI 720
+.01/-.035
FROM FACE OF BODY
7/16-20 UNF RH
O-RING
45°
1/2" HEX
This surface provides a metal to metal seal when
torqued into the seat. Appropriate handling is
required to not scratch or dent the surface.
(Part No. EC39EZ067)