US Stove furnace not putting out heat with coal

I have a US Stove 1557M wood/coal furnace. I have no problem burning wood but coal is giving me problems. I had a good bed of coal burning, then loaded up another 6" on top and it burned but was not putting out heat. I had the top damper closed and the bottom one fully opened, and it was not putting . out enough heat to turn on my fan. Any advice would be appreciated.

Wow!! I just asked about this same furnace today. Apparently, it's tricky to burn anthracite in from what I've been told. They do better on wood/bit coal.

Someone with more experience with this type of furnace will be able to actually help you out with it.

First you need a good draft, .06 or better.Crack open the ash door when you start it with coal for the first 1/2 hour or so.

I drilled a second air hole in my ash door 2 1/2" so I could run mine a little harder.

There are 2 air holes in the front cast iron piece that need to be closed off with a piece of steel or something like that.Those holes let air in over the fire and you want ALL air to go through the fire.

Also fill it with coal.They dont't burn well with 1/2 a load of coal.

That should get you started.

I've been using a Hotblast for 5 or 6 years now and It takes a little patience but they do work well when you get the hang of it.

I also replaced the thermister(fan switch) with a normal fan switch from my plumbing supply.
DON