Hi. I bought my 1939 home last fall. It has an old "octopus" / gravity furnace that has been converted to gas. It has worked very well until a few days ago. It would try to come on, but the burner would not stay lit. Now, it doesn't even attempt to come on. The thermostat is a LUX programmable (fresh batteries). When I set the temperature above the recorded temp, nothing happens anymore (it is turned on to heat setting). The standing pilot is lit and has a nice blue flame. There's another smaller flame that is lit just behind the pilot. I checked the circuit breaker and they're all fine. I really like this big monster and am wondering if anyone has any suggestions or thoughts why it won't come on anymore? Thanks!:confused:

Usually those old furnaces have a separate safety and the pilot is not 100% shut off. In other words the pilot will stay lit but the safety will not allow the burner to come on. Since it is old a few problems can come to play.

Parts may no longer be available so you might have to change to a more modern gas valve with 100% safety shut off.

It will be hard to tell you exactly what part is bad without part numbers but pictures will be the best.

They were great old units and would last forever but the utility bills will break the bank.

Can you post some pictures of the gas valve and the other electrical parts on the furnace so I can see exactly what you have. I used to work on these old ones when I was a young man many years ago.

Thank you for your help! Here is a link to the pictures of my furnace.

Photos

There is some type of motor on the side. There is an arm that lowers and opens the vents wider when the furnace would attempt to light (it doesn't attempt to do anything now).

If you click on the pictures, they get a little larger. I hope this helps! Thanks again!

WOW that is really a old one. I will say you will never find a part for that bad boy. That has the old style shuttle gas motor and all. They built them well and they did last a long time.

Sounds like the old spring wire/bimetal safety behind the pilot lite has given up the ghost preventing the unit from turning on.

The parts cannot be repaired and finding a replacement near impossible.

A very good old HVAC guy might be able to toss that old gas train and replace it all with one modern combination standing pilot gas valve.
Trying to find that old guy might be a problem because most are dead from cigarettes and alcohol. LOL.

Sorry I cannot be of more help.

Awww... I guess it's time to replace the monster. Thank you for all of your help!