Hydronic heat system freeze damage

[NoPlanB]

I purchased a northern Michigan cottage that had quite a bit of freeze damage to the hot water (& domestic water) heating system . The cottage is 930 sq feet, on a somewhat creepy 18" crawl with copper supply pipes and typical slant fin registers in the 6 rooms.

I've repaired the majority of damage in the crawl space while waiting for one of the 2 boiler certified contractors in the area to come out and inspect the boiler. Finally got one of them out last week, tested it and was told it's shot. A few days later he put together a quote.

While waiting I'd had a slightly out of area plumber come out to evaluate and quote some of the plumbing issues. Turns out he also does boilers & hydronic heat. He suggested that I pretty much tear out everything and start over with pex. He told me he's seen copper systems after major freezes repaired, pressure tested to 100 psi & yet weeks later leaks will still develop. I'm anxiously waiting for his proposal.

Does this make sense? Seems like a successful pressure test of a day or two at 100 psi you'd be good to go. I'm anticipating a very scary quote! Any suggestions or recommendations are appreciated.

 

[Jadnashua]

If you have power outages or some of the pipes run in uninsulated spaces, IMHO, it is somewhat foolish to not run the system with antifreeze in the system! This has a couple of advantages and disadvantages. You must make sure that you have proper, working and approved backflow equipment so that you don't contaminate the potable water, and adding antifreeze to the pipes means the heat transfer capacity of the piping is decreased, but it sure beats fixing split pipes! Keep in mind that using pex will not prevent the radiators themselves from freezing and being damaged. Pex by itself can expand enough to not be damaged by freezing, but the fittings you use, and anything you are using for your heat transfer appliance (slant-fin, radiators, etc.) will not like the freezing liquids.

Now, whether the whole system should be replace or not, can't say without knowing lots more. It likely is way oversized, which affects both economy and comfort, but it might survive for eons if you just switched to an antifreeze mix verses plain water.

 

[Sponsor]

 

[NoPlanB]

If you have power outages or some of the pipes run in uninsulated spaces, IMHO, it is somewhat foolish to not run the system with antifreeze in the system! This has a couple of advantages and disadvantages. You must make sure that you have proper, working and approved backflow equipment so that you don't contaminate the potable water, and adding antifreeze to the pipes means the heat transfer capacity of the piping is decreased, but it sure beats fixing split pipes! Keep in mind that using pex will not prevent the radiators themselves from freezing and being damaged. Pex by itself can expand enough to not be damaged by freezing, but the fittings you use, and anything you are using for your heat transfer appliance (slant-fin, radiators, etc.) will not like the freezing liquids.

Now, whether the whole system should be replace or not, can't say without knowing lots more. It likely is way oversized, which affects both economy and comfort, but it might survive for eons if you just switched to an antifreeze mix verses plain water.

Thanks for your reply. Yes the 27 year old freeze damaged boiler was 100k (very oversized) and of course didn't modulate down.

I've received 2 quotes to replace. First contractor suggested a floor Weil McLain boiler quite similar to what he'd put in 27 years ago for previous owner. Apx $5k. His other option was a WM 77000 Btu wall mount condensing & modulating boiler, about $6500 but eligible for $1000 in Rebates. He wasn't going to deal with repairing the crawl space supply plumbing & damaged slant fins.

Contractor #2 is at $9500 using a Navien, replacing all the supply system & slant fins, also tying in a separate domestic hot H20 tank with a recirculating pump to keep hot water instantly available at the farthest fixture.
He's also a plumber and been the only guy who seems to be willing to work in my 20" crawl space.

I had 2 more guys stop by yesterday so we'll see what they come up with.

Btw, everyone has recommended antifreeze!

These numbers put a huge dent in our budget so if anyone has any suggestions to heat this place for less I'd love to hear it. I'm pretty damn handy. If I had a basement I'd consider forced air, I'm taking the whole place down to the studs anyway.

Sorry for the long post.