My house has two floor heaters. I just inspected one of them and found that the bottom of the draft diverter is missing! There are deposits on the ground underneath the diverter. This doesn't seem like a good thing. I've attached some photos. How dangerous is this? Is it possible to buy a replacement draft diverter or would it need to be fabricated (the heater is very old)?

Do not run it. I doubt a replacement will be found. I'd look at replacing the unit...

How much do you use the thing? Floor heaters are rather inefficient. If you use it much, you would save enough in gas before long to pay the cost of a modern forced air furnace. Retro fitting ductwork could be a mess.

If the thing isn't used much, it might take years to pay for a new one on gas savings. However, you must have a safe system. That vent system has to go. Take a good look at the furnace itself. The heat exchanger or fire box should be heavy steel or cast iron, maybe lined with fire brick. If it is solid, it may last another 100 years.

I don't know if you can buy a draft diverter like that any more. Be careful of the old one, somebody may need it as a pattern to fabricate a new one. As for the elbows, look around at Lowe's or such, likely you can buy them and put them in yourself cheap.

If you could find somebody that knew what they were doing, it might be best to have them look it over. Beware of those that never saw one and figure the safest or most profitable thing it to tell you to buy a modern furnace.

Thanks very much for your answers.

This heater heats my house all winter, so I'm using it a lot.

I removed the draft diverter and showed it to two people who both said it looked like the bottom was supposed to be open. I then checked my other floor heater, which I thought I had already checked, and found that its draft diverter also has no bottom! Some of the exhaust gases must escape from the diverter box, but I guess that's the way it's designed.

A friend helped me replace the collar on the diverter and I replaced the elbows and the single-walled part of the flue. I'm going to have a heater expert out to inspect it ASAP to see if it needs to be replaced. If so, I might opt to have central heating put in instead, despite the additional cost.