ENVIRO-TEC
50
FORM ET115.24-NOM4 (819)
SECTION 5 - TROUBLESHOOTING
SYMPTOM
POSSIBLE CAUSE
CORRECTIVE ACTION
FAN RUNS BUT NO HEATING.
(ELECTRIC HEAT UNITS)
No power to electric heat
circuit on units with dual point
power.
Establish power to electric heat circuit.
Loose or improper wiring from
thermostat to electric heat
contactor.
Verify all wiring connections and terminations, and verify
proper wiring of thermostat.
Loose or improper wiring of
electric heat element.
Verify all wiring connections and terminations, and verify
proper wiring of electric heat element.
Defective electric heat
contactor.
With electric heat contactor energized, verify proper
voltage on contactor load terminals. Replace as
required.
Tripped or defective primary
high limit switch.
Turn thermostat to lowest set point and allow fan to run
10-15 minutes for limit switch to cool and reset. Then
turn thermostat to highest set point and check for proper
heating operation. If high limit trips again, check for the
following conditions: improper voltage to heater element;
obstructed fan or unit outlet reducing air flow over heater
element; dirty or defective heater element causing hot
spot. If heater does not operate after sufficient time
for limit switch to cool, disconnect power and check
continuity across primary high limit switch. Replace if
defective.
Tripped secondary high limit
switch.
Secondary high limit switches are designed to trip only
during extreme failure conditions. Contact factory before
attempting any corrective action.
Defective thermostat.
Momentarily jumper thermostat contacts to simulate
proper operation. Replace thermostat as required.
Defective electric heat
element.
Disconnect power and check continuity through heat
element. Replace as required.
Improper aquastat or change
over relay operation on units
so equipped. (Note: electric
heat will not operate when
hot water is present at the
unit.)
Verify proper aquastat position on piping, and verify
proper aquastat and change over relay operation.
Replace as required.
TROUBLESHOOTING REFERENCE
Component Description
Guide Name
Option Description
Fan Coil Relay Board (FCRB)
Fan Relay Board (FCRB) –
Installation, Operation and
Maintenance
1st generation relay board, 24V Control
Packages, units shipped before 3/31/2017
Fan Relay Board II (FRBii)
Fan Relay Board II (FRBii)
– Installation, Operation and
Maintenance
2nd generation relay board, 24V Control
Packages
G3 PWM Board
Fan Coil EC Motor IOM
ECM controller on variable speed ECM
units
NOTE:
All documents downloadable at www.enviro-tec.com.
Summary of Contents for VHA
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