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Should I replace my 30 year old boiler?

MSmithHH Member Posts: 25
edited August 2019 in Gas Heating
Hey folks,

I moved into my house 1 year ago. It has 3500 sq ft of heated space using baseboard radiators. There are high ceilings, many big windows, skylights, etc. Insulation is present. There is a 30 year old 160k Burnham boiler. It looks pretty good (i.e. pretty clean), but there is some rust along the bottom and where pipes go in and also it does leak water out of the pipe that runs along the side and points down, near the expansion tank (is that the pressure relief valve pipe?). Overall no issues last winter other than the leak.

I also plan to wall it in and finish that area of the basement off, meaning to keep an old fashioned boiler I'd need to add some kind of outdoor air exchange from what I understand.

So, between fixing the leak and the air exchange I figure it'll probably cost me at least $2000 to keep this boiler. I've heard 30 years can be the lifespan of these, but then I've also heard they can last for 60 years.

For sake of comparison I got a quote for a condensing high efficiency boiler (100k btu) with an indirect water heater (my current standard one is about 5 years old) and it is a substantial amount. I'm in Massachusetts and i think there's a couple thousand in rebates for it.

I've got 3 young kids, so I prefer not to deal with emergencies, but at the same time I don't want to waste a significant amount of money. Also I've loved the lack of maintenance the old fashioned boilers require vs what I hear about these new ones. If my current one most likely only has a few years left, I'd rather replace it now, but if odds are good that it could last 15 years I'd definitely keep it.

So, what would you do. Am I rolling the dice and taking on big risk by keeping it and investing the money to fix the leak and add the air exchange? Or are odds good that it could last another 15 years so it's a wise choice?



    HVACNUT Member Posts: 5,870
    Well, first of all, we dont discuss pricing on this forum.
    How long will the boiler last? How long will I last? We just don't know. You should get the system serviced, inspected, and have a combustion analysis done. Click on the Find a contractor in your area link at the top of the page. There are many great pros here. If you keep the existing atmospheric (I'm assuming. Regular chimney?) boiler and plan to close it to a confined space, then you absolutely need adequate combustion air.
    Without major work, Fan In A Can is a nice option and not terribly expensive or invasive.
    If you decide on a condensing boiler, or any type of heating equipment replacement, a heat loss calculation must be done. Where did 100K BTU come from?
    In the meantime, get that leak from the relief valve checked. Again, click the link. It could be just a bad valve or it could be a sign of larger problems.
  • MSmithHH
    MSmithHH Member Posts: 25
    Sorry. Good to know. I edited the quote price out.

    Too bad there's not better stats on longevity of them. Thanks for the response
    HVACNUT Member Posts: 5,870
    > @MSmithHH said:
    > Sorry. Good to know. I edited the quote price out.
    Reading back it seems I came off a little snotty. Wasnt trying to be. I know you're in Massachusetts, so in theory, I can undercut you're contractor and steal the job. That's not good. Rules suck but that's a good one.

    > Too bad there's not better stats on longevity of them. Thanks for the response

    The stats are, anywhere between 5 and 100+ years. Give or take a few. (ModCons need not apply.) The original owner probably would have had a prorated 30 year warranty on the cast iron block.
    If it's been properly serviced and maintained for 30 years, you might get 30 more. Hell, it's not a Burnham V7 or V8. That's a whole other enchilada.
    Do you have service records from the previous owner?
  • SlamDunk
    SlamDunk Member Posts: 1,596
    edited August 2019
    I would replace it. The original boiler in my house was 60 before it died. And, guess when it died? During winter.

    Also, you get benefits of fuel economy from improved boiler and burner design. Of course, these benefits hinge on a competent company.

    My old boiler was humongous, not maintained and cost 300-500/month to operate. I called the only mechanical contractor in town and he cranked up the pressure from 5psi to 10 psi. He was not a competent steam company and I was ignorant.

    My new boiler is half the physical size and it typically costs 150/month to run. The pressure is in the 9oz/sq in range.

    A lot has changed in thirty years but you need a good company to work with to benefit from the changes.
  • MSmithHH
    MSmithHH Member Posts: 25
    Ha, no worries. Makes sense

    > @HVACNUT The stats are, anywhere between 5 and 100+ years

    See that makes me think perhaps it doesn't make sense to do anything. I mean, someone could have had the same conversation when it turned 20 and here we are. Hmmmm..... No known service records though unfortunately.

    > @SlamDunk My new boiler is half the physical size and it typically costs 150/month to run.

    I hear that a dramatic drop in monthly price is more on the rare side. I hear too that the new mod-cons are only efficient in the ideal conditions and otherwise drops into the 80's for efficiency.
  • SlamDunk
    SlamDunk Member Posts: 1,596
    edited August 2019
    it is not rare at all. There are pro's on this board who save people lot's of $$$; sometimes without even replacing the boiler.
    That is why it is critical to find the right contractor.

    Boilers (even furnaces) have been sized incorrectly, maybe have other issues with radiator pitch or failed steam traps, poor combustion, lack of insulation...All of which contributes to high fuel consumption

    I cannot speak to mod-cons.
  • hot_rod
    hot_rod Member Posts: 22,353
    It's the modulation as much as the condensing that saves $$ with mod cons. Anytime a fixed output boiler short cycles on mild days or from being oversized, efficiencies easily drop into the 60% range.

    Even if the mod con doesn't condense all the time, the modulating reduces much of the in-efficient short cycle operation.

    I'd expect most systems to run low SWT on mild days, so even high temperature systems may all condensing operation for some of the heating season. Those fin tube still perform at 140F SWT, or lower which could allow condensing operation.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • JakeCK
    JakeCK Member Posts: 1,401
    Not a pro, but I recommend finding a trustworthy local shop to do a thorough inspection. Things like relief valves, thermocouples, and pumps are relatively quick and easy to change out. boiler sections not so much. A bad boiler section I would consider the kiss of death. Now I bet this will tick some people off here but bottom line is if the boiler is serviceable its probably more cost effective to maintain it then replace it. Can a new high efficency modcon save you money? Sure, but ask what the ROI is on it and I'd bet it would start to look a lot less attractive.
  • mikeg2015
    mikeg2015 Member Posts: 1,194
    CUrrent boiler is 130k output and you want ot replace it with 96k output. that makes some sense, since to get even 88% efficiency, condense you need to run a max of 160F water (140 return). The question is, what the the output of the radiation and what is hte heat loss of hte home. I suspect that in Mass, a 3500sqft home can be heated by 96k BTU. But at max fin tube output, you’ll only get 88k... which could be a little tight on capacity.