Troubleshooting Gas Heat

[Bobice]

Troubleshooting Gas Furnaces and Gas HeatersThere are many potential reasons that a furnace might not be working, but fortunately, many of the solutions are as easy as pressing a button. Use this chart to fix a wide range of conditions that prevent your furnace from working.

GAS AND FURNACE HEATER TROUBLESHOOTING CHART

Problem 

Possible cause 

Solution 

Furnace won't run

 

1. No power.

1. Check for blown fuses or tripped

    circuit breakers at main entrance

    panel, at separate entrance panel,

    and on or in furnace; restore circuit.

 

2. Switch off.

2. Turn on separate power switch

    on or near furnace

 

3. Motor overload.

3. Wait 30 minutes; press reset

    button. Repeat if necessary.

 

4. Pilot light out.

4. Relight pilot.

 

5. No gas.

5. Make sure gas valve to furnace is

    fully open

Not enough heat

 

1. Thermostat set

    too low.

1. Raise thermostat setting 5°.

 

2. Filter dirty.

2. Clean or replace filter.

 

3. Blower clogged.

3. Clean blower assembly.

 

4. Registers closed

    or blocked.

 

4. Make sure all registers are open;

    make sure they are not blocked

    by tugs, drapes or furniture.

 

5. System out of balance.

5. Balance system. 

 

6. Blower belt loose

    or broken.

6. Adjust or replace belt.

 

 

7. Burner dirty. 

7. Call a professional.

Pilot won't light

1. Pilot opening blocked.

1. Clean pilot opening.

 

2. No gas.

 

2. Make sure pilot light button

    is fully depressed; make sure

    gas valve to furnace is fully open.

Pilot won't

stay lit

1. Loose or faulty

    thermocouple.

1. Tighten thermocouple nut

    slightly, if no results, replace

    thermocouple.

 

2. Pilot flame set

    too low.

2. Adjust pilot so flame is

    about 2 inches long.

 

3. Electric pilot faulty.

3. Call a professional.

Furnace turns

on and off

repeatedly

1. Filter dirty.

1. Clean or replace filter.

2. Motor and/or blower

    needs lubrication.

2. If motor and blower have

    oil ports, lubricate.

Blower won't

stop running

1. Blower control

    set wrong.

1. Reset thermostat from

    ON to AUTO. 

 

2. Limit switch set wrong.

2. Reset limit switch

    for stop-start cycling.

 

3. Limit control

    needs adjustment.

3. Call a professional.

 

Furnace noisy

1. Access panels loose.

1. Mount and fasten access

    panels correctly.

 

2. Belts sticking, worn,

    or damaged.

2. Spray squeaking drive belts

    with belt dressing; replace worn

    or damaged belts.

 

3. Blower belts

    too loose or too tight.

3. Adjust belt.

 

4. Motor and/or

    blower needs

    lubrication.

4. If motor and blower

    have oil ports, lubricate.

 

 

5. Burner dirty.

5. Call a professional.

[ACtechGUY]

Additions to Bobice's troubleshooting gas furnaces.....

1. No power.

1. Check for blown fuses or tripped

circuit breakers at main entrance

panel, at separate entrance panel,

and on or in furnace; restore circuit.

Check wirenut connections where power enters furnace, they have a way of burning up.

2. Switch off.

2. Turn on separate power switch

on or near furnace

Check the switch itself. Switches have a way of going bad after 20 or 30 years:D

Not enough heat

2. Filter dirty.

2. Clean or replace filter.

That washable "Electrostatic" air filter is too restrictive to airflow causing furnace to overheat. Try a less restrictive filter.

Furnace noisy

1. Access panels loose.

1. Mount and fasten access

panels correctly.

2. Belts sticking, worn,

or damaged.

2. Spray squeaking drive belts

with belt dressing; replace worn

or damaged belts.

Blower wheel very dirty or some trash got sucked into the blower wheel causing unbalanced operation(shaking).

[Bobice]

 All we can add helps. Gives homeowners a "Warm and Fuzzy" feeling about Honest Technicians.