
2463 Merrell Road, Dallas, Texas 75229 • Phone: (972) 243-7425 • Fax: (972) 247-8674 • Toll Free: 1-888-HCC-1190
www.hoffmancontrols.com Form: 173-0229-001 Rev B
Temperature to Resistance Table - Key Point Values
Temp
ºF
Sensor
(Ohms)
Temp
ºF
Sensor
(Ohms)
Temp
ºF
Sensor
(Ohms)
40.0 26,109 64.0 13,823 88.0 7,685
42.0 24,712 66.0 13,139 90.0 7,332
44.0 23,398 68.0 12,492 92.0 6,997
46.0 22,160 70.0 11,881 94.0 6,679
48.0 20,996 72.0 11,3033 96.0 6,378
50.0 19,899 74.0 10,8509 98.0 6,092
52.0 18,872 76.0 10,2095 100.0 5,820
54.0 17,903 78.0 9,750 102.0 5,561
56.0 16,990 80.0 9,287 104.0 5,316
58.0 16,128 82.0 8,848 106.0 5,094
60.0 15,315 84.0 8,433 108.0 4,873
62.0 14,547 86.0 8,056 110.0 4,662
40.0 26,109 64.0 13,823 88.0 7,685
42.0 24,712 66.0 13,139 90.0 7,332
44.0 23,398 68.0 12,492 92.0 6,997
46.0 22,160 70.0 11,881 94.0 6,679
48.0 20,996 72.0 11,3033 96.0 6,378
50.0 19,899 74.0 10,8509 98.0 6,092
52.0 18,872 76.0 10,2095 100.0 5,820
54.0 17,903 78.0 9,750 102.0 5,561
56.0 16,990 80.0 9,287 104.0 5,316
58.0 16,128 82.0 8,848 106.0 5,094
60.0 15,315 84.0 8,433 108.0 4,873
62.0 14,547 86.0 8,056 110.0 4,662
40.0 26,109 64.0 13,823 88.0 7,685
42.0 24,712 66.0 13,139 90.0 7,332
44.0 23,398 68.0 12,492 92.0 6,997
46.0 22,160 70.0 11,881 94.0 6,679
48.0 20,996 72.0 11,3033 96.0 6,378
50.0 19,899 74.0 10,8509 98.0 6,092
52.0 18,872 76.0 10,2095 100.0 5,820
54.0 17,903 78.0 9,750 102.0 5,561
56.0 16,990 80.0 9,287 104.0 5,316
58.0 16,128 82.0 8,848 106.0 5,094
60.0 15,315 84.0 8,433 108.0 4,873
62.0 14,547 86.0 8,056 110.0 4,662
Above Selected Span and Range,
speed when temperatures are above the
If Sensor 1 is not connected, motor runs at full speed.
Always use Sensor 1 input.
Making unit ready for normal operation.
Disconnect power to the unit & reconnect the disabled com-
Reconnect power to the unit & observe operation.
Verify operation as described above by monitoring liquid line
temperature and observing motor speed.
Troubleshooting Guide
Check wiring, review instructions.
Additional 24 VAC transformer needed.
Check Heat Pump Mode Jumpers “DA”
Check wiring, review instructions.
Switch DA/RA jumper position.
Additional 24 VAC transformer needed.
Relocate per instructions.
Compare FLA rating to measured FLA.
Recharge system. Add or remove refrig-
erant. (Liquid line must not indicate
Adjust or replace expansion valve, cap
tube or orifice to provide proper control
Reset Range Adjust up (CW) to provide
evaporator temperature above 32°F.
Improper installation. Motor not wired correctly.
24 VAC not in phase with motor line voltage.
Sensor below 50°F up to 70°F.
Motor “OFF” on internal overload.
Heat Pump applications; control not providing full speed during
Motor not wired correctly.
Motor not wired correctly. Control damaged.
Low refrigerant. (Hot gas in liquid line.)
Sensor opened. (Verify Ohms vs. Temp.)
Sensor above 80°F up to 100°F.
Heat Pump Mode improperly programmed.
Minimum speed set too low.
Motor design not applicable for variable speed operation.
24 VAC not in phase with motor line voltage.
Sensor not properly located or attached to liquid line.
Fan blade does not load motor at full RPM (speed).
Sensor Ohms vs. Temperature measured not in compliance with
Motor design not applicable for
System not properly charged.
Low evaporation and head pressure.
Checkout Procedure Con't