58 Troubleshooting
7.2 Other Parts/Systems - Troubleshooting
Table 19 Blower troubleshooting
Symptom Possible Cause Check or Remedy
Blower will not start
No main power Check L1, L2 and L3 for rated voltage.
Blown fuse or tripped circuit
breaker (CB)
Check fuses or CBs to main fan.
Overloads tripped
Push reset button on main fan overload. Check
amp. draw.
No output voltage from
transformer
Check for 24 VAC between P24-2 and P24-1. If no
voltage, check primary voltage.
Control fuse blown or circuit
breaker tripped
Check for 24 VAC between P4-4 and E1. If no
voltage, check for short. Replace fuse or reset
circuit breaker.
Table 20 Econ-O-Coil chilled water troubleshooting
Symptom Possible Cause Check or Remedy
Chilled water valve not opening
Motor operates but valve won’t
open
Check linkage for adjustment and be sure that it is
tight on the valve.
Modulating Motors
No 24 VAC power to motor
Check linkage for adjustment and be sure that it is
tight on the valve.
No signal from control
Check DC voltage on printed circuit board in motor.
Terminal No. 1 is grounded and No. 3 is positive.
DC voltage should vary from 0.8 to 2.0 VDC or
above as temperature control is varied below room
temperature on cooling valve or above room
temperature on heating valve.
Motor not working
Remove wires on terminal No. 1 and No. 3 from the
motor (do not short). With 24 VAC power from TR
to TR jumper terminal 1 and 2 on motor to drive
open. Remove jumper to drive closed, if motor fails
to work, replace it.
Actuator Motors No 24 VAC power to motor
Check for 24 VAC between P22-3 and P22-5
(open), or P22-1 and P22-5 (closed).
Table 21 Compressor and refrigeration system troubleshooting
Symptom Possible Cause Check or Remedy
Compressor will not start
Power off Check main switch, fuses or CBs and wiring.
Current overload open
Reset manually on units with overload option. Allow
compressor to cool for internal overloads to reset.
Loose electrical connections Tighten connections.
Compressor motor burned out Check and replace compressor if defective.
Compressor will not operate,
contactor not pulling in
No call for cooling Check monitor status.
Liquid line solenoid valve not
energizing
Hold screwdriver over solenoid and check for
magnetic field. This indicates solenoid is energized.
Low pressure switch not making
contact
Check gas pressure - manually energize low
pressure switch.
Compressor will not operate,
contact not pulling in
High pressure switch open
Reset switch. Refer to other refrigeration
troubleshooting suggestions.
Compressor contactor pulled in
but compressor will not operate
Blown fuse or tripped CB
Check for line voltage after fuses or CBs, and after
contactors.
Compressor runs for three
minutes, then stops; contactor
drops out.
Low pressure switch not closing
Check for low gas pressure. Compressor is running
on Positive Start Kit (air cooled systems only).
Liquid line solenoid not opening Check magnetic field to see if energized.
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