The doors all fit really well, I did a light test and there's only a hair's width gap in certain spots. They cut all the contacting surfaces at the factory to make them perfectly aligned and flat, but of course metal on metal wont be 100% airtight even with a perfectly flat contact area. But yep, all the doors make great contact with their frames, no warping.
Alright I won't worry about sealing the fire door then. Believe it or not, it wasn't designed with a draft control on the fire door. It is the first of these furnaces I've seen with no sliding draft control on the fire door. Just as you see it in the photos, an oval hole with a perforated metal heat baffle attached over it. Clearly as designed. So a set level of air intake I guess? Also, there's a concave dip in the back of the oval at the top creating a gap between the plate and the door. I'll take a picture of it.
I love the mica idea, that's what I'll do for that. Do I need to keep the plate though too? I read that they are there to absorb excess heat to protect the doors from any warping and allow safe expansion/contraction. I'm thinking I could compress the mica between the plate and the door. The only problem is I'll still have to really peer in the small holes to see anything. Unless you guys think I can get away with doing away with the plate and just going with a bracket/mica.
Both doors have a latching mechanism. I was not happy about the fire door handle, it isn't broken.
Wouldn't have bothered me as much if it had been. Someone actually CUT the latching tab off of it, can you believe it? Was it really that wedged? If so though, why not just undo the nut holding the handle on? But yep, the saw cut is clear as day. No idea why people do these things. I am going to try to find a replacement handle or have a new tab welded on to it. Rockwood has it exactly right how it operates btw.
The ash door also latches, but it's a hook latch that the ash door tab just wedges into. You can see the frame with the latch on it above. But it latches nice and tight, same as the fire door would.
Yes, I must bring up the dreaded draft control (just read the old heated MPD thread) question. My chimney is 40' and has great strong draft all the time. So, barometric and an MPD? Or just a barometric? The heat exchanger pipe takeoff does have built-in holes for an MPD. And I was going to ask what the ideal reading on the manometer should be for this furnace. The pipe is 8" (if that helps), which is sized correctly for my chimney luckily. I like the idea of doing a permanent manometer mounted on the wall.
I love the clean out door too, a nice big 8" access to the heat exchanger for vacuuming. Really neat design thought there. The center hole is the bolt head for the cast iron heat absorption plate on the back of the clean out door. The tab with the hole would have been for additional draft control via the clean out. I only know this from the old catalogs showing the clean out door doing double duty as a clean out and additional draft door via chain control. Just pure weight keeps it closed.
Yep, that one tab had been overtightened completely tight to the adjoining tab, really unfortunate. There was a bunch of furnace cement missing there, so I think someone thought they'd just close the gap by doing that.
The weight alone of the exchanger is enough to make it seal when it's properly cemented, as you say just light even pressure is needed with the bolts.
Thanks for the enthusiasm Doug, I'm pretty excited too!
Not sure if anyone here on NEPA has taken one of these units on before now or not, but I'm guessing no? I'll be taking pictures all the way and bugging all of you with questions since I'm a newbie and have never burned coal before. All my knowledge I have now is from hours of reading all the fantastic information already here for a couple of years.
Franco, that's awesome! I never would have though of that. And I just found that the fire door frame has two knockouts for water lines in and out. And the firepot has a built in channel to accommodate them on the side. So I had found that it had a hot water coil option, but I never would have guessed the lines would have run to a small hot water tank inside.
Now on getting a good seal around the ash door, do I need to get a good seal around the smaller draft door in the ash door too?
One other question, when I build the cold air return box for the blower, can I run the first length of pipe off the heat exchanger through this for some heat reclamation as is done with modern forced air systems? Or is this a bad idea? Don't know if it would be safe or adversely affect stack temps.