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VI. CHECK INDOOR EXPANSION DEVICE
CAUTION: For proper unit operation and reliability,
units must be installed with balance port hard shutoff
TXV specifically designed to operate with Puron® two-
speed unit. Do not install with evaporator coils having
capillary tube metering devices.
A. FURNACE COILS
Puron® furnace coils come factory equipped with bi-flow, hard
shutoff TXV s specifically designed for Puron® two-speed units.
No changeout is required.
Remove existing Check-Flo-Rater™ piston from indoor coil and
install field accessory TXV.
Install TXV kit to indoor coil as follows:
IMPORTANT: The TXV should be mounted as close to the
indoor coil as possible and in a vertical, upright position. Avoid
mounting the inlet tube vertically down. Valve is more susceptible
to malfunction due to debris if inlet tube is facing down. A
factory-approved filter drier must be installed in the liquid line.
PROCEDURE 1—INSTALLING TXV IN PLACE OF PIS-
TON
1. Ensure coil has not been exposed to atmospheric pressure
for more than 15 minutes.
2. Remove indoor coil inlet tube at piston body inlet. Use
back-up wrench to prevent damage.
3. Remove piston retainer, being careful not to damage sealing
surface of O-ring.
4. Remove and discard factory-installed piston. Replace re-
tainer if O-ring is damaged.
NOTE: If the piston is not removed from the body, TXV will not
function properly.
5. Reinstall piston retainer in piston body.
6. Replace indoor coil inlet tube. Use back-up wrench to
prevent damage.
CAUTION: To prevent damage to the unit, use a brazing
shield and wrap TXV with wet cloth or use heat sink
material.
7. Sweat swivel adapter (See Fig. 6D) to inlet of indoor coil
and attach to TXV (See Fig. 6A) outlet. Use backup wrench
to avoid damage to tubing or valve. Sweat inlet of TXV,
marked “IN,” to liquid line. Avoid excessive heat which
could damage valve.
8. Install vapor elbow (See Fig. 6B) with equalizer adapter to
suction tube of line set and suction connection to indoor
coil. Adapter has a 1/4-in. male flare connector for attaching
equalizer tube.
9. Connect equalizer tube of TXV to 1/4-in. equalizer fitting
on vapor line adapter.
10. Attach TXV bulb to horizontal section of suction line using
bulb strap provided. (See Fig. 6C.) Insulate bulb with
factory-supplied insulation tape. (See Fig. 6E.) See Fig. 7
for correct positioning of sensing bulb.
11. Proceed with remainder of unit installation.
B. FAN COILS
Indoor unit (fan coil) comes factory equipped with a bi-flow
shut-off TXV specifically designed for Puron® two-speed. No
TXV changeout is required.
PROCEDURE 2—REPLACING R-22 TXV OR
NON-BALANCE PORT PURON® TXV
1. Remove any existing refrigerant and ensure coil has not
been exposed to atmospheric pressure for more than 15
minutes.
2. Remove coil access panel and fitting door from cabinet.
3. Remove and save TXV support clamp using a 5/16-in nut
driver.
4. Remove TXV using a backup wrench on flare connections
to prevent damage to tubing.
5. Using wire cutters, cut equalizer tube off flush with vapor
tube inside cabinet.
6. Remove bulb from vapor tube inside cabinet.
7. Braze equalizer stub-tube closed. Use protective barrier as
necessary to prevent damage to drain pan.
IMPORTANT: Route the equalizer tube of approved Puron®
TXV through suction line connection opening in fitting panel prior
to replacing fitting panel around tubing.
8. Install TXV (Fig. 6A) with 3/8-in. copper inlet tube through
small hole in service panel. Use wrench and backup wrench,
to avoid damage to tubing valve.
9. Reinstall TXV support clamp (removed in item 3).
10. Attach TXV bulb to vapor tube inside cabinet in same
location as original was removed using supplied bulb straps.
(See Fig. 6C.) Insulate bulb with factory-supplied insulation
tape. (See Fig. 6E.) See Fig. 7 for correct positioning of
sensing bulb.
11. Route equalizer tube through suction connection opening
(large hole) in fitting panel and install fitting panel in place.
12. Sweat inlet of TXV, marked “IN,” to liquid line. Avoid
excessive heat which could damage valve.
13. Install vapor elbow (See Fig. 6B) with equalizer adapter to
vapor line of line set and vapor connection to indoor coil.
Adapter has a 1/4-in. male flare connector for attaching
equalizer tube. (See Fig. 6B.)
14. Connect equalizer tube of TXV to 1/4-in. equalizer fitting
on vapor line adapter. Use backup wrench to prevent
damage to equalizer fitting.
15. Proceed with remainder of unit installation.
C. Long-Line Applications, Install Liquid-Line Solenoid
Valve (LSV)
For refrigerant piping arrangements with equivalent lengths
greater than 50 ft or when elevation difference between indoor
and/or outdoor unit is greater than ± 20 ft, follow all requirements
Fig. 5—TXV Installed
A91277
THERMOSTATIC
EXPANSION
VALVE
EQUALIZER
TUBE
SENSING
BULB
COIL
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