It's been quite some time since I was on this forum as I originally joined back when I purchased my first house with an Alaska 140 dual feed in it. Well I have since sold that house, but the Alaska provided me many of years of cheap heat and aside form the occasional blower, or the whole convection blower going bad (I blame the 2 floods it saw), it worked great. Fast forward to now, I purchased a new home this past summer with a high efficiency heat pump, a modcon propane boiler, and a VW V600 (I believe it's a 600). I would like to return to using the coal boiler if at all possible. The coal boiler and modcon boiler are piped in parallel to a feed my indirect hot water heater and a hydroair coil at the end of the air handler for the heat pump. The damper zoning panel handles all the calls and dampers, but when the heat pump can't keep up, it triggers a basic relay to fire the propane boiler's central heat call. The same would occur for the coal boiler's aquastat. What I'm trying to figure out is it worth using the VW boiler and repairing the DHW coil, or should I replace it? The original owner heated with an outdoor wood boiler, then used the VW boiler. Unfortunately he developed cancer and couldn't tend to anything anymore so the wife had the outdoor wood boiler sold and a modcon boiler added. It literally looks the like VW was shutdown one day and never touched again, ashes still in the ash pan, 55 gallon drum 1/2 filled, and a 5 gallon bucket of buck still sitting in a 1/4 full coal bin. Unfortunately he passed and a few years later she moved and listed the home for sale. I believe it's been 7 years since the coal boiler ran.
House information:
Chimney is 30-35+ foot and even with a manual damper they have in the pipe and it closed, the bypass holes would still snuff out a lighter when it was almost 50 out since it draws hard. It has a 6 inch flue with concrete chimney blocks that were insulated when installed.
3100 sqft, 2 story built 2003 (original was an old farmhouse they knocked down and then build new ontop) - R19 in the walls, R30 ceiling but getting additional R30 blown on top. Basement (original basement floor and a few fieldstone walls of the old farmhouse) is just over 6ft high where the boiler and hvac equipment lives. The rest of the basement is block 7 ft ceiling. HVAC is forced air with 2 zones, one upstairs and one downstairs. I really want to try and fire the coal boiler to help keep the basement dry as we have a high water table and it'd help keep me from running a dehumidifier down there all summer long.
VW boiler:
I believe it is a VA600 round door model based on the dimensions and pipe sizing. It is actually a left hand feed model which I understand is less common? It is currently plumbed parallel to the modcon so that you either open the large ball valves of the modcon or the coal boiler. From the boiler, there there are 2 zones, one being the hydroair coil and the other the indirect hot water heater. Currently no tstat or circulators are hooked to the coal boiler because they moved the wires and tstat to the modcon. So I would have to change the circulators back to the VW aquastat. It currently has an old Honeywell triple L8024A and a Honeywell s400a timer. Everything is still wired as it was originally except the the circulator wire has wire nuts on the end and not connected to any pumps and the tstate wire goes to nothing and lays in a coil on top. As for the connection to the chimney, there was no baro in the pipe (maybe cause the draft could suck a cat across the room in and they never thought about it?) but there was a manual damper in the pipe. Unfortunately there is not a lot of room there, 1x 90 out the back and turned up, 1x16in straight section, 1x90 into a reducer 8->6in, and that reducer it connected right into the chimney. There literally might be a total of 3.5ft of pipe there before the chimney.
In an effort to get an idea how sound everything was I first started with the gears and stoker in the back (mind you there isn't a heck of a lot of clearance behind the boiler). I checked that all the gears were tight with no sheer pins broke, I was able to hand turn the motor a few times to make sure everything was broke free from just sitting so long. Once I confirmed that everything seemed okay, turn on power to the aquastat and crossed the tstat wires - all the relays clicked and the stoker began running without a hitch. All augers, gears, fans etc seemed to run without any odd noises etc. Everything was really quiet actually except you can hear the coal (buck) being pulled by the auger from drum. I let it run for about 10 mins, all seemed well, so I shut it down. The next thing I checked was the the DHW coil since these often leak. I started tearing the rear panel and insulation off. That was a chore because there is a 1.25 main return running behind the unit so its already tight with that and then there is only about 2ft - 30 inches of clearance total behind it and the wall / the chimney thimble. I cut the original tankless coil lines because of the indirect WH (installed in 2017 + new expansion tank at that time). Once the rear panel was off it had the obvious DHW coil leak at some point in time and I believe even an old PRV at once point was leaking. It looks like they had replaced the PRV since it had leaked. I then cleaned up the coil and rusted area around it with some brushes and a shop vac and here was the end result. Sorry for the rough pictures but its fairly dark. You'll see the big return pipe that's kind of in the way. I need to clean the stoker back off cause a bunch of rust and junk fell on it otherwise it was just dusty / grimy before. It also appears one of the studs on the top (2nd once from the right) had been broken off at some point and never fixed. Even the part below the DHW coil with the bolts (I assume this is where the exhaust travels looks like it must have had water sitting on it as it had rust built up on it as well.
Is it worth fixing the DHW coil area by removing the nuts, plate and studs, then trying to have a plate welded over it, is the boiler kind of a lost cause cause of the damage etc from the coil? I mean it held water... I don't truly know the shape of the stoker assembly as it looks like it would literally be a nightmare to remove given the tight quarters behind the unity (2 ft I'd say between back of the firebox and the wall behind it. I checked the ash that was in the pan from the last time it was used and it looked good, matter of fact maybe even better than my 140's typically did so maybe the stoker and all are all working as intended. The original owner left multiple sheer pins, multiple augers, gears for the end of the auger that pulls coal from the drum etc. I just am not sure what they were all there for etc. I literally have no information and I'm figuring this out as I go. If it is too far gone, should I just replace the whole thing and call it a day. I got a quote for a new Keystoker ka6 for just under $8500 installed I was told, and if I went with the next step down, it'd be around $7500. The modcon currently has a net rating of just under 100k btu and that does the job no problem helping the heat pump, and tends to only need put out about less than 45k btus to help the heat pump when needed (even when it is 0). So I am not sure if I need the full KA6 or I can go for a lesser model. I would prefer to get the VW running as I am not looking to make the VW pretty or etc. I literally want it to just take over everything the modcon was doing. I'll even heat my DHW in the summer if I can keep the draft going. It can stay dirty, rusty, and hide in the dark basement as long as it does the job.
If I need to pull it to do all the repairs, how heavy is this thing, as it looks like a bunch of black steel pipe cutting, and it'll be a bear to move. I have a professional welder / fab guy who already agreed to come over and weld it onsite if I need to - I think there is enough room behind it for him to MIG weld it (may be a bit uncomfortable though). I also talked to Matt Direnzo who said he'd be able in a few weeks to come over and check it / fire it up, if I need as well. I am just afraid of dumping money into it if it's not worth it. Sorry for the long post but wanted to give all the details I had to make it easier to understand / visualize. I appreciate any insight or thoughts!
-Storm
