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Turn down the heat?

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chippy2
chippy2 Member Posts: 16
in THE MAIN WALL

I have a vacation home with hydronic heat and a non condensing boiler. Is it feasible to have house temperature at 50 degrees in winter and how does that affect the flue gas condensation? If the t stat is set to 50 each time I leave for a week, am I causing damage to the furnace and flue? I assume that the cold water in the system may cause condensation once the circulation starts? I also have a boiler controller function that can allow the circulator to remain off until boiler is up to temperature if that would help?

Thanks

Comments

  • BDR529
    BDR529 Member Posts: 372

    Splitin' hairs. Would be more concerned with freezing a water pipe.

    Heat Pipes are run out to the corners and outside walls it gets cold there.

    You know the house better than anyone. So, are you feeling lucky?

    ethicalpaul
  • chippy2
    chippy2 Member Posts: 16

    Ya there’s no piping in any outside walls and basement is well insulated. More concerned about effects on the boiler - if any. Thanks.

  • pecmsg
    pecmsg Member Posts: 6,781

    as long as the return water stays above 140* it’s fine.
    I don’t recommend keeping a home below 55°.

    do you have any type of alarm system for when something goes wrong?

    GrallertHomerJSmith
  • hot_rod
    hot_rod Member Posts: 26,609

    what type of heat emitters? Copper fin tube heats up quickly, cast radiators much slower

    But if the boiler has a control to hold the pump off, that offers cold return protection anyways. That was a common control logic on some Viessmann cast iron boilers

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 11,580

    If you were to keep the temperture at a comfortable 90° and reduced the temperature to 70° when unoccupied, would you worry about flue gas condensation? Reducing the unoccupied temperature by 20° when unoccupied to reduce fuel usage is a common practice. There is no danger to you boiler if the entire system is operated at a lower temperature. 50° just means that the boiler will cycle at a lower ambient temperature but it will still make high limit temperature (if needed) in about the same time frame as it would if you set the thermostat to 70°.

    If you have Cast Iron radiators then use the circulator delay feature all the time for boiler protection. If you have copper with fin baseboard, then that is probably unnecessary. Your control sounds like an upgrade from the old analogue limit devices of the 20th century. does that control have a thermal purge feature? If so, then I would use that feature to reduce fuel usage.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    ethicalpaul
  • chippy2
    chippy2 Member Posts: 16

    hi yes currently one zone of fin tube baseboard. (Eventually adding two more radiant floor zones). Controller is currently a Hydrostat 3250 plus…

  • Grallert
    Grallert Member Posts: 1,038

    There's no danger to the boiler. I would be concerned about the power to the boiler. Get a low temperature alarm that will alert you and or a trusted caretaker.

    Miss Hall's School service mechanic, greenhouse manager, teacher, dog walker and designated driver

    chippy2
  • chippy2
    chippy2 Member Posts: 16

    I do have a thermal purge feature I can set.


    One last question is about hi temp differential…factory set at 10degrees but in a colder/older house, would it make sense to make that 20 or 30° differential so that the circulator stays on longer if the heat is still being called for by the thermostat even though hi temp has been reached and the boiler turns off? Maybe I am misunderstanding the use of the differential?

  • HomerJSmith
    HomerJSmith Member Posts: 2,710
    edited November 18

    All boilers condense at some point in the heating cycle. What you should be concerned about is sustained condensation in a non-condensing boiler. Water returning to the boiler at 130 deg (they say less than) or less will condense, that is at start up. When the return water is above 130 deg. condensation diminishes. The longer the run cycle the better it is. How a boiler and flue react to cold weather is dependent on boiler type, atmospheric or fan assisted, etc.

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