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baseboard heating

dafy Member Posts: 19
Thinking about having antifreeze put into oil fired baseboard system pipes as we go to Florida for several months in the winter. Out of curosity-how long will water last in the system when the source is turned off?


  • Zman
    Zman Member Posts: 7,132
    It really depends on how your pipes are routed and insulated. Obviously, with no heat, your house will drop to outdoor temp and freeze the pipes in days. I have seen pipes that are poorly installed freeze after a few hours. Some systems hold out much longer.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Zman
    Zman Member Posts: 7,132
    edited December 2017
    Water will freeze at 32 degrees, the pipes will likely burst, it does not care what pipe or room it is in...
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Ironman
    Ironman Member Posts: 6,703
    AJinCT said:

    What about the water pipes to the bathrooms and kitchen? Those will freeze over.

    You either have to keep the house warm enough from freezing or have it winterized by removing all the water in the pipes. That usually means blowing out all lines with compressed air and antifreeze in the traps and water closets with the tanks drained.

    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    EBEBRATT-Ed Member Posts: 11,172
    Rereading @dafy post I believe he wants to put glycol in his heating system. I think he is asking what to do if water needs to be added to the system.

    @dafy, you can put 30% polypropylene glycol in your system which will protect it down to 10 degrees (slush point) bursting point is much lower.

    As far as makeup water/glycol if the system is tight and not leaking you do not need to add water. We have many commercial systems operating with no automatic water make up

    Check with the boiler manufacturer about glycol use in your boiler
  • HomerJSmith
    HomerJSmith Member Posts: 1,419
    I assume you are talking about make-up water. You are going to shut off and drain the domestic water that sources the boiler make-up? The boiler won't be running? You just want to protect the water in the boiler system from freezing?

    Without a leak in the boiler system, the water in that system would last forever. If you shut the source water to that boiler "off" and you plan to use that boiler, I would put a low pressure cut-off, perhaps, a Square D set at 10 psi. to shut down the boiler if the pressure drops below that level if your boiler doesn't come with that feature.

    Water chemistry is really important when Glycol is added to a system and probably done by someone who knows what they are doing. Caleffi has some very good synopsis on water chemistry in their "Idronic" series, which you can download.
  • HomerJSmith
    HomerJSmith Member Posts: 1,419
    How long anti-freeze will last in a system depends in several things: Operating temperature, Contaminants in the system, Quality of the mixed water, % of solution, Boiler usage, etc.

    Glyco in a system should be checked yearly and thoroughly check not more than 5 yrs.
  • HomerJSmith
    HomerJSmith Member Posts: 1,419
    I have systems that have glyco in them and the make-up water is cut off.

    "Hot Rod" has a video that show an Extrol 30 connected through a Caleffi fill valve set to the system pressure. It has a 100 psi gauge on it. The tank is filled with the glyco % of the boiler system and connected into the boiler piping. I use this setup to add make-up water to the system. A low pressure C/Out is important.

    The way that I do it is to fill the air bladder to 39 psi and pump the solution into the tank with a high head pump (70' hd) my gauge reaches 65 psi, shut the valves and connect it to the system.

    That was a good tip--"Hot Rod" Thanks.
  • ThomasCase
    ThomasCase Member Posts: 2
    Perhaps off-topic as you didn't ask, but why not leave the system on, albeit at a very low temp?

    I've got a cottage in northern WI (9500+ DD), with two zone baseboard hydronic. I've got anti-freeze good to +10 in the system and leave the thermostat at 40 °. Never a problem in 20 years (tom crosses fingers). Cost/Month for heat is about $40 in the winter and that's with me going up there every other week-end and cranking the heat......
    Mark Eatherton
  • Paul48
    Paul48 Member Posts: 4,470
    Not plaster walls...right?