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Troubleshooting

The chart assumes that the proper gas and pressure is available to the heater. The chart also assumes that the heater is used in accordance with Mr. Heater installation and operating instructions.
Problem Observed Possible Cause Solution
Motor starts, unit will not ignite. No spark. Igniter wire not connected. Remove top and reconnect.
    Improper igniter gap. Readjust to .050/.055. 1/8"
    Faulty transformer. Replace.
    Faulty spark plug/igniter cracked. Replace.
  Spark is present. No fuel or bad fuel. Drain use fresh fuel..
    Pump pressure incorrect. Adjust pressure to specs.
    Fuel filter blocked. Replace.
    Seal leak pump/motor.. Check, repair or replace..
    Restricted or worn nozzle. Clean or replace.
    Cracked or disconnected hose. Replace or reinstall.
  Runs with cover off. Dents in cone or cover deflect air flow through burner. Repair or replace parts.
    Fan blade bent, pitch off. Replace fan.
    Nozzle warm replace nozzle
       
Motor does not run or runs at slow speeds. Spark is present. Broken rotor or blades. Replace rotor, blades and nylon insert drive.
    Improper rotor clearance. Adjust to specs.
    Dirt on rotor face. Clean or replace.
    Faulty motor bearing. Replace motor.
    Open motor winding. Replace motor
    Faulty capacitors. Replace capacitor.
    Blade on motor bent or hitting housing. Repair dents or replace parts.
  No spark. Low voltage to heater Check electrical supply source and cord for a minimum of 105VAC.
    Bad igniter assembly. Replace.
Motor does not start. External causes. Broken or frayed wires on cord. Repair or replace cord.
    Faulty in-line thermostat. Repair or replace..
    Low voltage supply. Check electrical supply source and cord for a minimum of 105VAC.
  Internal causes. Faulty high limit switch. Test and replace if necessary.
    Reset button not reset fully. Completely push in or replace.
    Bad circuit board. Repair or replace.
    Bad motor capacitor Replace
Heater ignites and burns but than shuts off in less than a minute. Safety control trips out. Faulty or dirty photocell. Clean or replace.
    Faulty safety control/printed circuit board. Replace.
  Unusual order or burning of eyes. Dirty photocell. Clean photocell and check for correct pump pressure.

  Poor fuel flow from low pressure. Adjust correct air pressure.
    Air filters restricted or dirty. Clean or replace.
    Restriction in nozzle or burner head. Clean nozzle and burner or replace.
    Fuel cap not vented. Clean or replace.
Heater runs for 30 minutes then puffs and shuts off. Not running. Transformer going bad. Replace.
Frequent plug fouling or delayed ignition. Starts hard. Spark plug location. Adjust location per specs.
    Wrong or dirty fuel. Drain and replace with clean, correct fuel.
Cannot adjust air pressure. Smokes or burns eyes poor heat. Worn nozzle. Replace.
    Air leak. Check air lines for cracks.
    O-ring missing between filter plate and compressor plate. Replace.
    Air line fitting or filter body loose. Tighten.
    Plugged nozzle. Clean or replace.
    Defective nozzle seal/O-ring. Replace.
    Dirty output filter. Replace.
    Dirty seat or ball in relief valve assembly. Clean relief valve and seat.
    Spring in relief valve stuck or defective. Replace spring.
    Worn or broken rotor or vanes. Replace rotor and vanes.
    Hose barb on pump cracked Replace
Runs indoors but not out doors in cold weather Not running. Water in fuel. Drain replace fuel and fuel filter.
    Improper fuel. If weather is below zero degrees,(-18C), kerosene should be used as only fuel. It may also be necessary to add a de-icer.
    Low air pressure. Adjust pressure. Clean or replace air filters. Check for air leaks or restriction in fuel and air lines.
    Incorrect nozzle or spark plug adjustment. Adjust nozzle spacing. Check spark plug alignment.
IF SERVICE IS REQUIRED
For information regarding service, please call our Toll-Free Number: 1-800-251-0001. Our office hours are 8:30 a.m. - 5:00 p.m., Eastern Time Zone, Monday through Friday. Please include the model number, date of purchase, and description of problem in all communication.
WARRANTY
Mr. Heater warrants Mr. Heaters and accessories to be free from defects in material and Workmanship for a period of 1 year from date of purchase. Mr. Heater will repair or replace this Product free of charge if it has been proven to be defective within the 1 year period, and is Returned at customer expense with proof of purchase to Mr. Heater within the warranty period.
IF SERVICE IS REQUIRED
For information regarding service, please call our Toll-Free Number: 1-800-251-0001. Our office hours are 8:30 a.m. - 5:00 p.m., Eastern Time Zone, Monday through Friday. Please include the model number, date of purchase, and description of problem in all communication.


TROUBLESHOOTING
Original Series Tank-Top Heaters
Big Buddy
Big Max
Portable Buddy
Convection Heaters
Forced Air Kerosene Heaters
Forced Air Propane Heaters
Garage / Shop Heaters
Patio Heaters
Radiant Portable Heater (Model MH35LP)
Radiant Portable Heater (Model MH125LP)
Tube Heaters