There is a fair amount of seepage around the edges and the bolts of the faceplate on the tankless coil on my Burnham V14 boiler. When the boiler comes on regularly for heating, the moisture evaporates and just leaves a lot of mineral deposits, but in the summer I have the boiler on a timer so it only comes on three times per 24 hours. Things get pretty wet that way. I had the same problem about a decade ago, pulled the coil and replaced the gasket. That held for a year or two. I'm about to give it another shot. Is there a better than the standard (rubber IIRC) gasket material available? Is there any sort of goop-in-a-tube that could be used with the gasket, or by itself? I suspect to find quite a bit of pitting on the boiler where the coil plate is mounted and on the surface of the matching surface of the plate as well. The bolts look badly corroded. Any advice on how to get them out with the least chance of their snapping off? Would I be better off just leaving the thing alone and put up with the wetness till I need to replace the 18 year old boiler with a new one and a hot water tank? Thanks

I've been planning on replacing my hot water boiler, which is old but runs fine, with a more efficient one and hopefully taking advantage the energy tax credit. I got a quote last week before realizing that I didn't really know enough what to ask (and before finding this site). I'm hoping to get a couple of answers and some advice before getting more quotes. Old Boiler: 135000 BTU Janitrol from the 60s, which multiple people have said is probably about 60% efficient. It heats the house just fine, and seems to cycle off quite a bit even on the coldest days, so I assume it's got plenty of power to spare. The house is 1500 sf and 90 years old, but a lot of things have been tightened up on the house over the years. The Quotes: 90000 BTU Slant Fin 84% efficient boiler, replacing the expansion tank, adding a few copper pipes and additional zoned shutoff valves, circulation pump, redoing some venting, $4850, plus $1000+ more for removing the old one by an abatement company. - or - 120000 BTU Slant Fin 94% efficient boiler, and everything else above, $7300 (plus removal). This one would qualify for the tax credit, which was my hope, but thinking about it now, seems bizarrely oversized. It looks like this is maybe the smallest high efficiency boiler that Slant Fin makes, so perhaps that is the best this guy could offer. These quotes were a 15 minute appt where the guy looked at the old boiler and that was it. Anyway, after reading a bunch of info here, I started doing a Heat Loss Calculation online based on my best guesses, and it's coming up at roughly 60k-65k BTU, but could be off a few thousand depending on the details. If I'm doing it right, that's isn't far off from what I'd expect given the existing boiler and would almost make sense with the 90000 BTU/84% efficient boiler quoted. So my main question is just how bad is it to have an oversized boiler? In the example above, the high efficiency one costs only $1000 more ( $7300-4850-1500 tax credit). At 10% more efficient, I'd make that back at some point, unless it is going to wear out earlier or need more maintenance or just run inefficiently due to being sized wrong...how do I put a dollar figure on that? Even the regular efficiency one quoted seems oversized somewhat....a 80k BTU one could do it. But how exact can I expect to get? I'm sure I don't want accidentally go too small either. Right now, I'm hoping I can find a 70k-75k BTU high efficiency one for notably less than high efficiency quote I got that I can feel good about going with. Is there anything else I am missing? I've read all the recommendations of a full home energy audit, but anything beyond that? Any good questions I should ask the next guy?