Gas Floor Furnace quit working

Just post as much information on the thing as you can find — make, model, year. Photos… no need for you to look it up, but odds are pretty good that someone will know just what it is.

Would not surprise me if the 'control box' was nothing more than a 120 VAC to 24 VAC transformer, and then there is the gas valve and a thermocouple.

Someone probably needs to crawl under there with a meter and see what is going on. Probably not much there.

Has the thermostat has been bypassed to eliminate that as the cause ? Probably the easiest thing to check first.

Chances are that your gas valve is powered by 750 millivolts. That power is generated by the pilot flame burning on the pilot power generator. There are several items that connect the electrical parts to make the millivolts open the gas valve.

• First there is the power generator sometimes called a power pile.
• Next there is a Gas Valve that uses that power
• Then there is the thermostat that opens and closes the electric current based on the room temperature
• Then there may be a Limit switch or even more limit switches placed in different locations around the furnace in order to keep the furnace from overheating.

Some of these limit switches may have a manual reset. If you have a manual reset limit, that may be the reason you have no heat. Follow the wires to see if there are any limit switches. See if those switches have a tiny button between the wire connectors and press it. If you feel a slight click when you push it then it was tripped. If you do not feel a slight click then it was not tripped.

Another reason for no heat is the power generator thermopile may be defective.

Here is a wiring diagram that might be close to what you have in your floor furnace.

If you are not comfrotable playing with the safety controls on a gas appliance then i would suggest you call a professional for service. but pushing a reset button on a limit control is usually a DIY first step. If the limit trips again, then you need to find the cause. The safety switches are there to let you know something is wrong and needs further attention. Don't bypass them.

What kind of questions do the professionals ask?

You should say "I have Gas Heat and the heater is not working". When I quote you the amount of $$$ I charge for a service call visit, and you reply " Sounds good, when can you get here?" That is all the information I need to send a technician.

There has to be more than one professional HVAC or Plumbing/Heating company in your area. Just call another one that has less questions.

EDIT: Who sells you the fuel you use? the gas company may have someone that knows how to fix your heater. Remember, As long as the furnace is not working, the gas company is not selling any gas. It is in their best interest to get your furnace working again.

As far as the "Find A Contractor" link, A contractor needs to sign up to be listed. in the great state of California, I guess there are not too many contractors that look for help here at HeatingHelp.com. I know here in South Carolina, where I moved to retire, there are none.

you need to make some friends you can refer people to. a floor furnace that won't fire is in the realm of something anyone that is basically competent can figure out although they may hate you for sending them in a crawlspace.

Hi @mattmia2 , I'm very careful with referrals. I'm of the "go slowly and do it well, and just once" bent. Too many are of the "go fast and mess up" approach. I don't want my name attached to that. And, although I don't mind crawlspaces, just guessing I'm in the minority. 🤠

Yours, Larry