Carrier 25HCR Check Defrost Thermostat, Position of Sensing Bulb, Defrost Thermostat Location

10 O'CLOCK

2 O'CLOCK

STRAP

SUCTION TUBE

8 O'CLOCK

7⁄8 IN. OD & SMALLER

SENSING BULB

4O'CLOCK

LARGER THAN 7⁄8 IN. OD

STEP 6 —Check Defrost Thermostat

Check defrost thermostat to ensure it is properly located and securely attached. There is a liquid header with a brass distributor and feeder tube going into outdoor coil. At the end of the one of the feeder tubes, there is a 3/8 in. O.D. stub tube approximately 2 in. long. (See Fig. 5.) The defrost thermostat should be located on stub tube. Note that there is only one stub tube used with liquid header, and on most units it is the bottom circuit.

FEEDER TUBE

STUB TUBE

25HCR

A81032

Fig. 4 ---Position of Sensing Bulb

Replacing TXV on Puron Indoor Coil

1.Pump system down to 2 psig and recover refrigerant.

2.Remove coil access panel and fitting panel from front of cabinet.

3.Remove TXV support clamp using a 5/16-in. nut driver. Save the clamp.

4.Remove Puron 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 R-22 TXV through suction line connection opening in fitting panel prior to replacing fitting panel around tubing.

8.Install TXV with 3/8-in. copper tubing through small hole in service panel. Use wrench and backup wrench, to avoid damage to tubing or valve, to attach TXV to distributor.

9.Reinstall TXV support clamp (removed in item 3).

10.Attach TXV bulb to vapor tube inside cabinet, in same location as original was when removed, using supplied bulb clamps (nylon or copper). See Fig. 4 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 with equalizer adapter to vapor line of line set and vapor connection to indoor coil. Adapter has a 1/4-in. male connector for attaching equalizer tube.

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.

DEFROST￿

THERMOSTAT

A97517

Fig. 5 ---Defrost Thermostat Location

STEP 7 —Make Piping Connections

!WARNING

PERSONAL INJURY AND ENVIRONMENTAL HAZARD

Failure to follow this warning could result in personal injury or death.

Relieve pressure and recover all refrigerant before system repair or final unit disposal. Use all service ports and open all flow-control devices, including solenoid valves.

!CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage or improper operation.

If ANY refrigerant tubing is buried, provide a 6-in. vertical rise at service valve. Refrigerant tubing lengths up to 36-in. may be buried without further special consideration. Do not bury lines longer than 36 in.

!CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage or improper operation.

To prevent damage to unit or service valves, observe the following:

S Use a brazing shield

S Wrap service valves with wet cloth or use a heat sink material.

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