Modine Manufacturing HD - Service & Troubleshooting; Pilot does not light; Main burners do not light (Pilot is lit)

IHR Series Manual
20 21
4.0 Maintenance • Troubleshooting
Symptom Code Possible Cause Corrective Action
Burning of gas-air
mixture inside
plenum (flashback).
A, B
A, B
A, B
A, B
A, B
• Heater mounted at incorrect angle.
• Excessive drafts.
• Gas leaking or blocked orifice/venturi.
• Separation of ceramic grids.
• Ceramic grids cracked.
• Mounting angle 20°-35° from horizontal.
• Relocate or shield from draft.
• Do not operate. Check with leak detector solution.
• Do not operate. Replace rayhead.
• Do not operate. Replace rayhead.
Delayed ignition. A
A, B
A, B
A, B
A, B
• Electrode out of specification.
• Low gas pressure.
• Partially blocked orifice.
• Improper orifice size.
• Incorrect gas.
• See Figure 4.3.
• See Gas Supply section.
• Clean or replace.
• Consult dealer.
• Do not operate. See nameplate. Correct immediately.
Low ceramic surface
temperature, exces
-
sive rollout or soot on
rods.
A, B
A, B
A, B
A, B
A, B
A, B
A, B
A, B
• Dirty or plugged rayhead ceramics.
• Partially blocked orifice.
• Low inlet gas pressure.
• Low manifold gas pressure.
• High manifold pressure.
• Foreign matter in venturi tube.
• Gas supply piping too small.
• Incorrect gas.
• See maintenance instructions.
• Remove and clean.
• See Gas Supply section.
• Adjust main valve regulator for 6” W.C. natural
gas, 10” W.C. propane.
• Adjust main valve regulator for 6” W.C. natural
gas, 10” W.C. propane.
• See Maintenance Section.
• Increase inlet pressure or replace.
• Do not operate. See nameplate. Correct immediately.
Control system
overheating.
A, B
A, B
• Heater not mounted correctly.
• Heater mounted too close to ceiling.
• Mounting angle 20°-35° from horizontal.
• Observe clearance to combustibles safety chart
located on heater reflector. Do not operate.
Gas odor. A, B
B
• Loose pipe connection.
• Pilot not lit.
• Check all connections with leak-detector
solution, tighten as necessary.
• Cycle thermostat or manually light.
Heater cycles
repeatedly.
A, B
A
A, B
A, B
B
• Heater located in drafty area.
• Low gas pressure.
• Thermostat located in drafty area.
• Weak pilot flame.
• Defective flame detector.
• Relocate or shield from draft.
• See Gas Supply section for propane.
• Replace thermostat.
• Clean or adjust pilot.
• Replace.
Pilot on, no gas to
main burner.
B • Weak pilot flame.
• No electrical power to unit.
• Pilot sensor element not located in pilot flame.
• Defective main valve solenoid.
• Defective pilot generator or thermocouple.
• Excessive thermostat wire length with millivolt
system.
• Manual valve off.
• Clean or adjust pilot.
• Check thermostat, manual switch or circuit
breaker.
• Locate upper 3/4 of element in pilot flame.
• Isolate. Measure resistance, replace if “0”.
• Replace.
• Wire not to exceed length provided by factory.
• Turn to “ON” position.
No spark; no ignition. A
A
A
A
A
A
A
• Lack of 120V or 24V incoming voltage.
• Open high voltage wire.
• Improper electrode gap.
• Loose or open wire connection.
• Poor or no equipment ground.
• Unit in “safety lockout” mode.
• Defective “gas lighter” control.
• Proper voltage needed or repair wire.
• Isolate and measure resistance, replace if “0”.
• See Figure 4.3.
• Check all wires, tighten or replace.
• Trace ground wire for complete circuit back to
equipment ground from control.
• Interrupt power source, repeat trial for ignition.
• Verify proper voltage. Replace.
Heater lights, and
“locks out” after
approximately 10
seconds.
A
A
A
A
A
• Poor or no equipment ground.
• Polarity is reversed.
• Low gas pressure.
• Electrode not sensing.
• Heater mounted at incorrect angle.
• Check all connections, provide positive earth
ground.
• 120V to black, neutral to white.
• See Gas Supply section.
• Relocate or replace if defective.
• Mounting angle 20°-35° from horizontal.
Spark is present. No
main gas operation.
Unit “locks out”.
A
A
A
• Gas valve in “Off” position.
• Defective main valve solenoid.
• Defective “Gas lighter” control.
• Turn to “On” position.
• Isolate and check for resistance. Replace if “0”.
• Verify proper voltage. Replace.
Heater will not
shut off.
A, B
A, B
A, B
• Defective thermostat or wiring.
• Gas valve stuck open.
• High gas pressure.
• Replace or repair.
• Replace.
• See Gas Supply section.
Code: A - Direct Spark Ignition (24V/120V) B - Standing Pilot (Millivolt)
Chart 4.1 • Troubleshooting Guide