Mestek SEPARATED COMBUSTION GAS FIRED PROPELLER UNIT HEATER Installation Instructions & Parts List page 25

SYMPTOMS
O. Fan will not run.
P. Fan motor turns on and off
while burner is operating.
Q. Fan motor will not stop.
R. Not enough heat.
T. Too much heat.
U. Cold air is delivered on start
up.
V. Cold air is delivered during
heater operation.
W. No Spark.
Power Vented Propellers Troubleshooting Guide
POSSIBLE CAUSE(S)
1. Loose wiring.
2. Defective motor overload protector or
defective motor.
3. Defective fan switch.
1. Fan switch heater element improperly
wired.
2. Defective fan switch.
3. Motor overload protector cycling on
and off.
4. Motor not properly oiled.
1. Improperly wired fan control.
2. Main burners not lighting while
thermostat calls for heat.
3. Defective fan switch.
1. Incorrect gas input.
2. Heater undersized.
3. Thermostat malfunction.
4. Heater cycling on limit control.
1. Thermostat malfunction.
2. Heater runs continuously.
1. Fan switch heater element improperly
wired.
1. Incorrect manifold pressure or input.
2. Voltage to unit too high.
3. Air through put too high.
1. Thermostat not calling for heat.
2. No low voltage.
3. Spark gap closed or too wide.
4. Broken or cracked ceramic on spark
electrode.
25
CORRECTIVE ACTION
1. Check and tighten all wiring
connections per diagrams. Thermostat
wires tagged "W" and "G" must be
connected together (unless special
thermostats are used; if so, see
thermostat wiring diagram). See
electrical connections.
2. Replace motor.
3. Check for 24V across "H" terminals
on fan time delay switch. If 24V is
present, jumper terminals numbered 2
and 4. If motor runs, the fan switch is
defective and must be replaced. If 24V is
not present, check wiring per diagrams.
1. Be sure fan switch heater terminals
are connected per diagrams.
2. Replace fan switch.
3. Check motor amps against motor
name plate rating, check voltage,
replace fan motor if defective.
4. Refer to label on motor.
1. Check all wiring.
2. Refer to H or N symptoms.
3. Replace fan switch.
1. Refer to "Operation".
2. This is especially true when the
heated space is enlarged. Have the
heat loss calculated and compare to
the heater output (80% of input). Your
gas supplier or installer can furnish
this information. If heater is under
sized, add additional heaters.
3. Replace thermostat.
4. There should be NO ducts attached to
the front of this heater. Check air
movement through heat exchanger.
Check voltage to fan motor. Clean fan
blade and heat exchanger and oil fan
motor.
1. Replace thermostat.
2. Check wiring per diagrams; Check
operation at valve. Look for short
(such as staples piercing thermostat
wiring), and correct; Replace gas
valve; Refer to "Operation".
1. Be sure fan switch heater terminals
are connected per diagrams.
1. Refer to "Operation".
2. Check motor voltage with fan running.
Should be 115 volts AC.
3. Refer to "Operation".
1. Close thermostat contacts.
2. Check for 24V across 24V terminals
of S8600.
3. Set gap to 0.1".
4. Replace pilot assembly.