Hoffman
|
Controls
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
Table 1
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
c.
Above Selected Span and Range,
The motor(s) will start
and remain at full speed when temperatures are above the
high end of the range adjust
.
d.
Simple Test:
If Sensor 1 is not connected, motor runs at full speed.
Important:
Always use Sensor 1 input.
Step 3
Making unit ready for normal operation.
1.
Disconnect power to the unit & reconnect the disabled com-
pressor.
2.
Reconnect power to the unit & observe operation.
3.
Verify operation as described above by monitoring liquid line
temperature and observing motor speed.
Troubleshooting Guide
1.
Check wiring, review instructions.
2.
Additional 24 VAC transformer needed.
See "
GENERAL
" section instructions
3.
Normal operation.
4.
Motor protected.
5.
Check Heat Pump Mode Jumpers “DA”
and “RA”.
1.
Check wiring, review instructions.
2.
Replace control.
3.
Charge system.
4.
Replace Sensor.
5.
Normal operation.
6.
Switch DA/RA jumper position.
1.
Raise Min. RPM speed.
2.
Replace motor.
1.
Additional 24 VAC transformer needed.
See "
GENERAL
" section instructions
2.
Relocate per instructions.
3.
Compare FLA rating to measured FLA.
4.
Replace Sensor.
5.
Replace Motor.
6.
Recharge system. Add or remove refrig-
erant. (Liquid line must not indicate
vapor/gas.)
7.
Adjust or replace expansion valve, cap
tube or orifice to provide proper control
of lowside.
8.
Reset Range Adjust up (CW) to provide
evaporator temperature above 32°F.
Motor Will
Not Run
Motor Runs
at Full Speed
Only
Motor
Overheats
1.
Improper installation. Motor not wired correctly.
2.
24 VAC not in phase with motor line voltage.
3.
Sensor below 50°F up to 70°F.
4.
Motor “OFF” on internal overload.
5.
Heat Pump applications; control not providing full speed during
defrost cycle.
1.
Motor not wired correctly.
2.
Motor not wired correctly. Control damaged.
3.
Low refrigerant. (Hot gas in liquid line.)
4.
Sensor opened. (Verify Ohms vs. Temp.)
5.
Sensor above 80°F up to 100°F.
6.
Heat Pump Mode improperly programmed.
1.
Minimum speed set too low.
2.
Motor design not applicable for variable speed operation.
1.
24 VAC not in phase with motor line voltage.
2.
Sensor not properly located or attached to liquid line.
3.
Fan blade does not load motor at full RPM (speed).
4.
Sensor Ohms vs. Temperature measured not in compliance with
values in Table 1.
5.
Motor design not applicable for variable speed operation.
6.
System not properly charged.
7.
Expansion valve is not properly metering refrigerant; cap tube or
orifice not properly sized for low ambient operation.
8.
Low evaporation and head pressure.
Motor Will
Not Modulate
Properly
Condition
Cause
Solution
Condition
Checkout Procedure Con't
