Carrier OUTDOOR FROST THERMOSTAT Heat Pump Units, Ð Outdoor Frost Thermostat Oft, 52S SERIES

52S

SERIES

INDOOR THERMOSTAT (Heat Pump Units) (cont) (Figure 54) Ð To verify operation of the heat pump in-

door thermostat switch, a continuity test may be per- formed as follows:

1.Turn off unit power as described in GENERAL DISASSEMBLY section.

2.Remove wire leads from thermostat. Note their loca- tions to ease re-assembly.

3.To test stage A, place one lead of the continuity tester on the terminal marked 2, and the other lead on either the terminal marked 1 or the terminal marked 3.

4.Adjust the thermostat up or down to verify the con- tacts of the switch open and close. When verifying continuity of the closed switch, the reading on the meter should be 0 ohms. An open switch will show OL on the meter.

5.To test stage B contacts, place one lead of the conti- nuity tester on contact 5 and the other lead on either contact 4 or contact 6.

6.Adjust the thermostat up or down to verify the con- tacts of the switch open and close as in Step 4.

7.When testing is complete, reconnect the leads.

1	BLK
2
3	BLU
ORN
4	GRY
5
6	BRN
IT

FIGURE 54 Ð INDOOR THERMOSTAT (IT) CONTACTS, ALL 52SQ AA AND CP MODELS

OUTDOOR FROST THERMOSTAT (Heat Pump Units)

(Figure 55) Ð The Outdoor Frost Thermostat (OFT) is a thermostat that uses a single-pole switch with a manual override selector. The thermostat switches be- tween electric heat and compressor operation when the temperature of the outdoor coil falls below 15 F or rises above 35 F. Switching the override selector to elec- tric heat disables the reverse cycle operation of the thermostat is manually switched to electric heat opera- tion, the compressor is disabled for heating and cool- ing operations.

To verify the OFT is operational, a continuity test may be performed as follows:

1.Turn off unit power as described in GENERAL DISASSEMBLY section.

2.Remove the leads from the OFT. Note their locations to ease re-assembly.

3.Connect the continuity tester to the switch terminals marked 1 and 2.

4.Rotate the override switch to the electric heat setting and verify that there is continuity between termi- nals 1 and 2.

5.To check the other contacts, move the lead on termi- nal 1 to terminal 3. Rotate the override switch to the heat pump setting. There should now be continuity between terminals 2 and 3.

6.Once the test is complete, reconnect the leads.

FIGURE 55 Ð OUTDOOR FROST THERMOSTAT (OFT)

CONTACTS, ALL 52SQ AA AND CP MODELS

LEGEND (Figures 53 - 55)

COMP Ð Compressor

FCS	Ð Fan Control Switch
IT	Ð Indoor Thermostat
OFT	Ð Outdoor Frost Thermostat
OL	Ð Overload
PLS	Ð Primary Limit Switch
SLS	Ð Secondary Limit Switch
TBH	Ð Thermostat Bulb Heater

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