New Door Seals Leaking? :(

Hello all,

Replaced the door seals on my furnace last Friday and lit her up. Haven't been able to get the stack temp below 150° all week, and have found a low spot in the ash pan door seal. Planning to shut down and try again tomorrow, just not sure what happened . I didn't "pull" the rope, made sure it was bunched into the channel and not stretched...

For a little history, I replaced the seals in 2011 when I started burning. Used 1/2" rope then, as the channel measures 1/2" wide. Seemed to work fine, but have never been able to "choke" the fire with this furnace. Nor sure if that's a separate issue or not. Fast forward to last year, replaced the seals again just for maintenance. Again used 1/2" rope, but the doors didn't seem to close as tightly as before. Kind of like when the seals are new and not broken in, only they never broke in (it stayed like that all winter). I assumed it was due to accumulated cement in the channel, as I had no good way to clean it all out...

So, this year, I removed both doors from the furnace and thoroughly cleaned the channels to bare metal. As said, resealed last week with 1/2" and I can tell it's leaking somewhere. Did the dollar bill test and found only one notable spot, can feel it when running your fingers over the gasket too.

My question is, should I try 5/8" rope, or will that be too fat to close the doors? Or is it something I did wrong? Only thing I did different this year is using only a spot of cement every few inches, rather than a continuous bead like in previous years. After finding out how miserable it is to clean, didn't want to use any more than necessary. Can't find any info on the furnace to indicate what size gasket rope was originally spec'd for the unit.

Any help appreciated, thanks

Joe

If you are going to shut down anyway try the 5/8, you said 1/2 didn't seem to shut as tight as before most likely it was 5/8 at the beginning. No harm trying it, no big dollars lost if it doesn't work go back to 1/2 but I would try it.

Hello,

Thanks for the reply. Just to clarify (since I'm terrible at explaining things ), when I said they didn't seem to close as tightly, that was last year. And by not closing as tight, it almost seemed like the rope was too fat (the latch for the ash door wouldn't go to 9 o'clock, but only like 10 o'clock as the door wouldn't close as far).

This year, they close nicer (just that one leak that I found has me bothered). Would think that if the rope were too small, it's be leaking all around. Just not sure what I could've done wrong, followed all of the guidelines and did exactly as I did before.

For what it's worth, this furnace has never been able to "choke" a fire for as long as I've used it. Not sure if it's a door leak or somewhere else, will look into while it's down.

I do agree on the trying 5/8", cheap enough. My worry about redoing it again after this is having to shut down again. Seems like it wastes a lot of coal to build a new fire and start over .

Thanks,

Joe

joe
...im no expert...but im not sure what a 'keystoner kogen' is... ( as per your avatar)
but if it is a 'stoker feed'...ur not gonna 'choke' it too much

Hi Joe,
what could be done is to remove the seal, clean all the old cement. Put a layer of H.T. silicone cement in the channel (easier when removing the door and placing it on a table) and place the new 1/2" or 5/8" rope gasket over the silicone. Wait till the silicone begins to dry (not sticking and flexible). Hang the door and close it, don't force it too much so the rope gasket and the silicone will just take the form of the door's channel and give you a perfect seal.
If you use the 1/2" gasket, put a little more silicone to be shure to compensate for the uneven channel.
I preffer to use a smaller paper than a dollar bill, like a 1/2" wide paper, easier to find exactly where the leak/s come from.