Problems with home heating fuel systems

Natural gas and propane burn cleaner than fuel oil, and most gas furnaces present fewer operational difficulties than oil burners do. In fact, the problems that affect gas furnaces typically involve the furnace's thermocouple, the pilot light, or some component of the electrical system.

Look for your problem, and solution, on the handy chart on the next page.

Problem	Possible Cause	Solution
Furnace won’t run	No power	Check for blown fuses or tripped circuit breaker at main entrance panel, at separate entrance panel and on or in furnace; restore circuit.
	Switch off	Turn on separate power switch on or near furnace
	Motor overload	Wait 30 minutes; press reset button. Repeat if necessary
	Pilot light out	Relight pilot
	No gas	Make sure gas valve to furnace is fully open
Not enough heat	Thermostat set to low	Raise thermostat setting 5 º
	Filter dirty	Clean or replace filter
	Blower clogged	Clean blower assembly
	Registers closed or blocked	Make sure all registers are open; make sure they are not blocked by tugs, drapes or furniture
	Systems out of balance	Balance system
	Blower belt loose or broken	Adjust or replace belt
	Burner dirty	Call a professional
Pilot won’t light	Pilot opening blocked	Clean pilot opening
	No gas	Make sure pilot light button is fully depressed; make sure gas valve to furnace is fully open
Pilot won’t stay lit	Loose or faulty thermocouple	Tighten thermocouple nut slightly, if no results, replace thermocouple
	Pilot flame set too low	Adjust pilot so flame is 2’
	Electric pilot faulty	Call a professional
Furnace turns on and off repeatedly	Filter dirty	Clean or replace filter
	Motor and/or blower needs lubrication	If motor and blower have oil ports, lubricate
Blower won’t stop running	Blower control set wrong	Reset thermostat on to auto
	Limit switch set wrong	Reset limit switch for stop-starting cycling
	Limit control needs adjustment	Call a professional
Furnace noisy	Access panels loose	Mount and fasten access panels correctly
	Belts sticking, worn, or damaged	Spray squeaking drive belts with belt dressing; replace worn or damaged belts
	Blower belts too loose or too tight	Adjust belt
	Motor and/or blower needs lubrication	If motor and blower have oil ports, lubricate
	Burner dirty	Call a professional