Limit Switch?

[JoanneJ]

My heater quit working today. The fan works if I put it in the on position. The pilot is lit and it is trying to fire up, but doesnt.
Do I really need to pay someone $100 an hour to replace this $10 part? Can it be done by the homeowner fairly easily?

[tritontr]

What is the make and model number of your furnace? Can you give any more information when you say"trying to fire up". If your limit switch is not allowing your furnace to operate this is a safety device and could indicate you have a more serious problem . Anytime a safety device is suspected especially on a gas furnace you should call a licensed HVAC tech to check out the furnace.

[Robert]

Hi,


How long since furnace last fired and worked properly ?


IF it has been a while, the furnace should have cooled enough to allow limit to close and reset itself.


Have you tested it with ohm meter to see if any of the limits are actually open ?


One thing to consider and very good reason to call a tech is it could have opened on an actual overheat saftey situation, THEN failed and not closing once cooled meaning switch is bad, but there IS still a problem with furnace operation.


Thought I'd shed some light on why these type tasks can be dangerous for DIY.



Thanks,
Robert