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Wood stove supplemental heat - freezing pipes

Bought an old house with no insulation in walls. Will address that at some point... But this last winter I turned down the heat too much overnight. Setpoint was 50 at night in one zone, dropping from 70, It was -30F outside and in the time span from 70-50 inside, the pipes in the wall cavity froze. They did not burst, merely froze enough to prevent flow. I addressed some of those issues with insulation where I could get at it and thermostat set pint, the pipes did not freeze at -60F with wind chill. Very happy with that!

I am concerned that using a wood stove would tell the thermostat that the temperature is ok, no need to run boiler and therefore the pipes will freeze yet again.

I know that running water does not freeze easily. Is there a way to set my circulation pump on a timer to run once every hour during the night for 5 minutes? I don't need the boiler to run I think.

Let me know your thoughts.

Comments

  • Zman
    Zman Member Posts: 6,807
    The problem is that as soon as the water stops moving it will freeze, sometimes very quickly.
    I think your best bet is to do a 30% proplyne glycol mix in your heat system
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • DuggieFresh5
    DuggieFresh5 Member Posts: 48
    A simple, if wasteful method is to leave a faucet at a slow drip when you know temps are likely to cause an issue. I had an old house that I heated with coal and had to balance central heat vs the stove myself.

    Also - pipe heating cable works great. I put some on an outlet w/it's own breaker. Just flipped on the breaker when temps outside were likely to cause a problem - for me that was most of the winter past January. I was dealing with pipes in an uninsulated crawl space.
  • icesailor
    icesailor Member Posts: 7,265
    A more third world solution for you, because you are obviously living in a 3rd world environment, would be to rig your boiler to have the burner not run but you be able to run the circulator continuously when it is cold outside and the pipes might freeze.

    That's if you are talking about heating pipes to radiators that are buried in the wall. If its potable water pipes, the only solution is to blow out the pipes with air until you are ready to use water in the AM.

    Glycol is an alternative. So nasty that I can't even describe what a PITA it is to deal with. Any time you need to do something to the system, you need to drain it out and save it for re-use.

    I once brought up something like that with my wife about a cold house etc. She told me that if I liked the cold so much, I could sleep outside for as long as I liked. Alone. She'd be staying inside, and not to be futzing with any boiler settings or there'd be a permanent division with me on the outside, with her, the kids and the animals inside with her. That if I could convince the dog to move outside with me, the dog was welcome to go. The cat would be staying with her on the bed. Probably with the wussie dog too.
    Bob Bona_4
  • Bob Harper
    Bob Harper Member Posts: 882
    First of all, don't be offended please but can you afford to live there? The house will need the attic bypasses sealed then insulated first--top priority. Next, seal the upper level air leaks such as leaky windows. You can use heat shrink wrap if need be but it needs to be as tight as a duck's rear end. If you have radiant heat pipes freezing in walls, get an IR thermography to map out where the pipes are and inject dense pack insulation into those stud cavities. By circulating cold water, you can destroy your boiler. Better to have it fire more often and circulate a little. Install a bypass loop and adjust to maintain a return water temp of about 140F. If the boiler's thermostat is too close to the woodstove, move it further away. Woodstoves heat by radiant heat primarily and are zone heaters. Don't expect too much out of it. Get a rod and brush and sweep monthly until you know how often it needs it. Hopefully, it is vented into a UL listed liner or chimney system and not masonry. Once you've sealed the upper half of the thermal envelope, less cold air should infiltrate the lower areas thus reducing your heating needs. Long standby times for a boiler can kill the boiler and chimney. Allow it to fire more often for shorter burns if need be.
  • RobG
    RobG Member Posts: 1,850
    I agree with Carl, the easiest and most foolproof solution is to add antifreeze to the system. Make sure it is done by a pro who knows what he is doing and uses a refractometer to make sure the proper percentage is correct for the lowest temps.

    Rob
  • OldMNHouse
    OldMNHouse Member Posts: 7
    Zman said:

    The problem is that as soon as the water stops moving it will freeze, sometimes very quickly.
    I think your best bet is to do a 30% proplyne glycol mix in your heat system

    Thanks for your response. I know this is an option, but I'd prefer not adding glycol to my pipes.
  • OldMNHouse
    OldMNHouse Member Posts: 7

    A simple, if wasteful method is to leave a faucet at a slow drip when you know temps are likely to cause an issue. I had an old house that I heated with coal and had to balance central heat vs the stove myself.

    Dealing with radiators, so this is not an option...

    Also - pipe heating cable works great. I put some on an outlet w/it's own breaker. Just flipped on the breaker when temps outside were likely to cause a problem - for me that was most of the winter past January. I was dealing with pipes in an uninsulated crawl space.

    I'd prefer a less risky option, I've seen heat tapes fail in the wrong way in the past.
  • OldMNHouse
    OldMNHouse Member Posts: 7
    icesailor said:

    A more third world solution for you, because you are obviously living in a 3rd world environment, would be to rig your boiler to have the burner not run but you be able to run the circulator continuously when it is cold outside and the pipes might freeze.

    This kind of solution is what I was wondering about, is this easily achievable? I have three heating zones, how would I rig a solution like this?

  • OldMNHouse
    OldMNHouse Member Posts: 7

    First of all, don't be offended please but can you afford to live there? The house will need the attic bypasses sealed then insulated first--top priority. Next, seal the upper level air leaks such as leaky windows. You can use heat shrink wrap if need be but it needs to be as tight as a duck's rear end.

    I had an energy audit. My house is leaky, lets just say that... I did spend a week in the attic digging through 6" of blown in cellulose to find all attic bypasses and joints which I cualked/spray foamed and covered up completely. On top of that I blew in another 16" of cellulose. Overkill I know, because of other leaks, but it reduced the heating bill by 30%.

    My 140 year old windows are relatively leaky, but I am working on solutions for them.

    If you have radiant heat pipes freezing in walls, get an IR thermography to map out where the pipes are and inject dense pack insulation into those stud cavities.

    I like this idea and I might check it out. I had an insulation company quote me $4000 to fill all exterior walls with insulation, but if I can limit it to the passageways where the pipes run, I can probably start there.


    By circulating cold water, you can destroy your boiler. Better to have it fire more often and circulate a little. Install a bypass loop and adjust to maintain a return water temp of about 140F. If the boiler's thermostat is too close to the woodstove, move it further away. Woodstoves heat by radiant heat primarily and are zone heaters. Don't expect too much out of it. Get a rod and brush and sweep monthly until you know how often it needs it. Hopefully, it is vented into a UL listed liner or chimney system and not masonry. Once you've sealed the upper half of the thermal envelope, less cold air should infiltrate the lower areas thus reducing your heating needs. Long standby times for a boiler can kill the boiler and chimney. Allow it to fire more often for shorter burns if need be.

    How would I allow it to fire more often and with shorter burns?

    Thanks
  • icesailor
    icesailor Member Posts: 7,265
    You have all the answers. Here's another answer to another unasked question.

    In MY experience, what you are trying to do (on the cheap) will guarantee you frozen and broken pipes, Guaranteed!

    If you try to just run the circulators and cold water through the system, sooner or later, they will freeze and plug up. If they don't, its because the radiation installed is sucking the heat out of the house, making you cold.

    There's never enough time to do it right. But always time to do it over after the pipes break and cause all kinds of water damage.
  • OldMNHouse
    OldMNHouse Member Posts: 7
    icesailor said:

    You have all the answers. Here's another answer to another unasked question.

    In MY experience, what you are trying to do (on the cheap) will guarantee you frozen and broken pipes, Guaranteed!

    If you try to just run the circulators and cold water through the system, sooner or later, they will freeze and plug up. If they don't, its because the radiation installed is sucking the heat out of the house, making you cold.

    There's never enough time to do it right. But always time to do it over after the pipes break and cause all kinds of water damage.

    So what would you propose I do? I have a stove that was moved from a different location in the house (not installed to code by previous owners and in a 200 sqft room, (stove is claiming good for 1500 sqft) that I plan to install in a masonry chimney with an insulated UL listed chimney liner.
    My concern is that with this stove running, my pipes will freeze. IMO, I don't mind the heat being sucked out of other areas, this will force the boiler to kick off.

    I have time to do it right, but I don't like the idea of the glycol in my pipes.
  • Don_197
    Don_197 Member Posts: 184
    1) Don't do deep setback 2) Set up your aquastat (temperature control) to not allow your boiler temp to fall below 140 (150-155 if it is on the supply side) 3) Wire an outdoor sensor to bypass your pump control when it gets down below 15 degrees to run your pump continuously. (make sure that your boiler fires to that minimum temperature any time the circ pump is running) Cost? 90 dollars for the Penn or Johnson Controls mechanical outdoor sensor, and the extra money you pay for utilities to have to run your boiler at this minimum temp when it is 15 degrees or colder outside. Any time you are going to rely on the boiler as your main source of heat, you will necessarily have to turn the temperature controller up to whatever it takes to maintain your house at a given temperature.
    icesailor
  • icesailor
    icesailor Member Posts: 7,265
    Anti-Freeze sucks. I put it in dog houses when I must.

    They advertise that wood stove to heat 1500 sq ft. They didn't bother to tell you at what temperature it would the 1500 feet to. heat
  • Bridgerman
    Bridgerman Member Posts: 2
    Sorry to jump in after a lull in the conversation, but there is a product you can attach to your thermostat that will call for water to circulate periodically. It is called ThermGuard.

    I live in Montana and have a wood stove I use with my radiant baseboard heat. My pipes froze and burst causing some expensive repairs and remodeling of my finished basement.

    I put a ThermGuard on 3 zones. Two zones are to back bedrooms that I leave the thermostats turned off. The other zone goes through an unheated space.

    My ThermGuards are set to circulate 3 minutes of water every 3 hours. And, if the thermostat actually calls for heat, the ThermGuard timing is reset so if a zone comes on during the night, ThermGuard will skip that cycle.

    Freezing pipes with a wood stove or pellet stove is a very real problem. Good luck with whatever solution you move forward.

    John
  • Jamie Hall
    Jamie Hall Member Posts: 16,640
    Your title says it all -- wood stove SUPPLEMENTAL heat. You have two choices -- get a big enough wood stove (or stoves) to heat the whole house, and plan to keep them going all the time -- then it's not supplemental -- or use that boiler for your base heat, and use the wood stove to kick it up when you want things warmer. I'd suggest leaving the boiler thermostat set to hold the house warm enough to avoid freezing pipes -- say 60 or so. You may have to experiment. Don't use a setback. Then when you've had enough of the arctic blast, use the wood stove to thaw yourself out.

    If you are using airtight stoves for the efficiency, make sure that the chimneys are swept clear -- you can do it yourself, if the chimneys are good -- several times a season. Or keep the driveway plowed so the fire department can get there...

    Been there, done that, have the T shirt, and I ain't going back.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • icesailor
    icesailor Member Posts: 7,265
    I just read a local newspaper from where I used to work and live at.

    Someone had a perfectly good hydronic system in their home. They were using wood supplemental/primary heat. The house froze up. After they discovered the chimney fire, and the house burned too the ground. What is still standing, is covered with ice from the fire department. Who again, kept their record of never loosing a chimney.

    Expensive savings, burning wood.

    Not an old house and chimney. Probably less than 20 years old.