Reversing Valve - Carrier R-22 Application Manual And Service Manual

PISTON
(ORIENT AS SHOWN)
STRAINER
BRASS
HEX NUT
PISTON
RETAINER
WEATHERMAKER™ PRODUCTS EXCEPT 1992 PRODUC-
TION
1. Shut off power to unit.
2. Pump unit down using pumpdown procedure described in this
service manual.
3. Loosen nut and 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 it.
5. Slide piston out by inserting a small, soft wire with small
kinks through metering hole. Do not damage metering hole,
sealing surface around piston cones, or fluted portion of
piston.
6. Clean piston refrigerant-metering hole.
7. Install a new retainer O-ring or retainer assembly before
reassembling bypass-type AccuRater™.
WEATHERMAKER™ AND CUBE PRODUCTS PRODUCED
IN 1992
1. Shut off power to unit.
2. Reclaim outdoor-unit refrigerant.
3. Loosen brass hex nut and remove line from brass hex body.
4. Slide piston out by inserting a small, soft wire with small
kinks through metering hole. Do not damage metering hole,
sealing surface around piston cones, or fluted portion of
piston.
5. Clean piston refrigerant-metering hole.
6. Always replace Teflon seal with new seal. Never try to reuse
old seals.
7. Reassemble brass nut and brass hex body. Be sure orientation
is as shown in Fig. 47.
Step 6—Reversing Valve
In heat pumps, changeover between heating and cooling modes is
accomplished with a valve that reverses flow of refrigerant in
system. (See Fig. 48) This reversing-valve device is easy to
troubleshoot and replace. The reversing-valve solenoid can be
checked with power off with an ohmmeter. Check for continuity
and shorting to ground. With control-circuit (24v) power on, check
for correct voltage at solenoid coil. Check for overheated solenoid.
FEEDER
TUBES
TEFLON
BRASS
SEAL
HEX
BODY
A91138
Fig. 47—AccuRater™ Components
PISTON BODY
PRODUCTION
EXCEPT 1992
With unit operating, other items can be checked, such as frost or
condensate water on refrigerant lines.
The sound made by a reversing valve as it begins or ends defrost
is a whooshing sound, as the valve reverses and pressures in
system equalize. An experienced service technician detects this
sound and uses it as a valuable troubleshooting tool.
Using a remote measuring device, check inlet and outlet line
temperatures. DO NOT touch lines. If reversing valve is operating
normally, inlet and outlet temperatures on appropriate lines should
be close. Any difference would be due to heat loss or gain across
valve body. Temperatures are best checked with a remote-reading,
electronic-type thermometer with multiple probes. Route thermo-
couple leads to inside of coil area through service-valve mounting-
plate area underneath coil. Fig. 49 and 50 show test points (TP) on
reversing valve for recording temperatures. Insulate points for
more accurate reading.
If valve is defective:
1. Shut off all power to unit and remove all charge from system.
2. Check valve design. If valve is of the 3-port design and new
replacement is of the 4-port design, replacement of the
solenoid coil and wire leads is necessary. Valve bodies are
interchangeable, but solenoid and wires are not. Three-port
reversing valve and solenoid coil with leads must be used
together. New solenoid coil cannot be used on a 3-port valve.
Four-port reversing valve uses solenoid with quick-connect
terminals for leads connection. Old solenoid coil cannot be
used on 4-port reversing valve. If for any reason a new wire
cord is not available, cut the leads on the old solenoid coil as
close to the coil as possible. Terminate the leads with 2 female
1/4-in. quick-connects. Connect terminals to new solenoid and
tape connection to insulate and provide moisture barrier.
Replace these wires as soon as wire cord is available. See
RCD (Replacement Component Catalog) for proper cord part
number.
3. Remove solenoid coil from valve body. Remove valve by
cutting it from system with tubing cutter. Repair person should
cut in such a way that stubs can be easily brazed back into
system. Do not use a hacksaw. This introduces chips into
system that cause failure. After defective valve is removed,
wrap it in wet rag and carefully unbraze stubs. Save stubs for
future use. Because defective valve is not overheated, it can be
analyzed for cause of failure when it is returned.
41
PISTON
PISTON RETAINER
FLARE ADAPTER
INTERNAL STRAINER
A94004