Carrier WEATHERMASTER III 38HQ - Manual (Page 15)

1. Attach pressure gage to suction service port.
2. Frontseat the liquid line valve on the outdoor
coil section.
3. Start system and run until suction pressure
reaches 5 psig (see Caution) or low-pressure
switch opens.
4. Shut off system. Frontseat vapor line valve on
outdoor coil section.
5. Vent remaining pressure.
AccuRater™ (Bypass Type) Servicing — See
Fig. 15 for bypass-type AccuRater components. The
piston has a refrigerant metering orifice thru it.
The retainer forms a stop for the piston in the
refrigerant bypass mode, and a sealing surface for
liquid line flare connection. To check, clean or
replace piston:
1. Shut off power to unit.
2. Pump unit down using Pumpdown Procedure
described previously.
3. Remove liquid line flare connection from
AccuRater.
4. Pull retainer out of body being careful not to
scratch flare sealing surface. If retainer does not
pull out easily, carefully use locking pliers to
remove retainer.
5. Slide piston out by inserting a small, soft wire
thru metering orifice (18-gage thermostat wire).
See that metering orifice, sealing surface around
piston cones and fluted portion of piston are not
damaged.
6. Clean piston refrigerant metering orifice.
7. Replace retainer O-ring before reassembling
bypass-type AccuRater. Carrier O-ring part no.
is 99CC501052.
Liquid Line Strainer (protects AccuRater) made
of wire mesh is located in the liquid line inside
indoor fan-coil unit behind liquid line service
valve (Fig. 9). Liquid line is belled and sweat con­
nected where strainer is located. If strainer is
plugged, unsweat belied liquid line connection and
replace strainer.
Compatible Fitting Repair
LEAKING MECHANICAL CONNECTION —
Frontseat outdoor section service valves and relieve
refrigerant pressure in tubing and compressor
section. Back off locknut from Carrier Compatible
Fitting onto tube. Cut fitting between threads and
seal ring bead as shown in Fig. 17. Remove tubing
section remaining in threaded portion of fitting.
Discard locknut.
Clean, flux and insert new tube end into remain­
ing portion of Carrier Compatible Fitting. Wrap
valve base (outdoor unit) in wet cloth. Heat and
apply low-temperature solder (430 F).
LEAKING SWEAT CONNECTION — Frontseat
service valves and relieve refrigerant pressure in
tubing. Clean and flux area around leak and apply
low-temperature solder (430 F).
Evacuate or purge indoor fan-coil, compressor
section and tubing system. Add refrigerant charge
as described in Service, Refrigerant Charging.
LEAKING FLARE CONNECTION — Cut and
reflare 3/8-in. system liquid line.
MAINTENANCE
CAUTION: Eefo/® pedbrmstj^
Fig. 15 — AccuRater™ (Bypass Type)
Components
OUTDOOR FAN MOTOR BEARINGS are pre­
lubricated for 3 years heavy duty or 5 years normal
duty. When lubrication is necessary, it should be
lubricated in a motor repair shop.
Outdoor Coil Cleaning — Ensure power to unit is
shut off. Clean the outdoor unit coil with water at
the beginning of every cooling season or more often
if required. Use ordinary garden hose at a pressure
high enough to clean efficiently. For best results,
unscrew and remove unit top cover (grille).
Insert hose nozzle between fan blades and spray
coil fins from inside-to-outside the unit. If unit has
a double-row coil, loosen screws to separate coils,
carefully pull outer row of coils away slightly from
inner row. Do not strain coil tubing connections.
Flush dirt toward outside of both coils. Flush dirt
from basepan by spraying water thru top of unit.
Avoid splashing mud on coil or water on fan motor.
Make sure that water drainage holes under outdoor
coil are not obstructed.
15