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Oil boiler and tankless domestic water heater... Winterizing with RV antifreeze

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arcticman
arcticman Member, Email Confirmation Posts: 24
I plan on winterizing our home with RV antifreeze this year. I want to winterize the hot an cold domestic water system with RV antifreeze the night before I shut down the house completely. I need to keep the boiler operational overnight for heat... then drain and winterize the boiler and zones in the morning to complete the shutdown.

My question is... is it okay to have RV antifreeze in the tankless domestic water heater in the boiler while the boiler is still operating at 190 degrees?

Thanks

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  • WMno57
    WMno57 Member Posts: 1,408
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    RV antifreeze is for DWV traps and toilets. I would not introduce it into a domestic water system, hot or cold. Everyone I know with summer cabins, winterize by draining the domestic water system. They all have forced air. For your boiler, I would either drain it, or use an antifreeze specifically for hydronic systems.

    I don't know how you should handle the tankless water heater.

    Where is this home located? What kind of Boiler? Pictures?
  • arcticman
    arcticman Member, Email Confirmation Posts: 24
    edited December 2021
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    Thanks for your reply... you may have not understood my question... I'll try to clarify.

    RV antifreeze is specifically made for domestic water system. It is commonly used in our area to winterize homes. I have been using it for years in our RV's water system... it is totally safe. For the past several years I have been winterizing our house by draining and using my compressor to clear all the water from the system. But it is a very time consuming process to guarantee all the water is removed from the plumbing. ( its a big house, not a cabin).

    Pumping RV antifreeze through the system will take considerably less time and I won't have to worry about any water being left in the system. Its also much easier to winterize the appliances... washing machine, dishwasher, refrigerator with ice maker etc.

    The home is in Alaska. The boiler is a Well McClain WTGO-5. It has a built in tankless on demand domestic hot water coil. I'm sure many of you are familiar with this boiler.

    Back to my question. When I pump the RV antifreeze throughout the hot and cold domestic plumbing the the coils in the tankless water heater inside the boiler will be filled with antifreeze. I want to keep the boiler running to heat the home until I'm ready to shut down the boiler.

    The boiling point of RV antifreeze is 216 degrees F. So it should be okay if its in the coils of the tankless water heater but I want to make sure.

    I would appreciate any replies from those who may have experience or opinions.

    Thanks
  • WMno57
    WMno57 Member Posts: 1,408
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    Now that you mention it, none of the cabins I'm familiar with (northern Michigan) had dishwashers or ice makers. Now I know why.
    Sorry I can't provide a better answer. Hopefully someone will come along who has some other methods for winterizing.
    I friend of mine sold his Chicago area house to a developer. The developer's ultimate plan was to tear it down and build a strip mall. The city dragged their feet on rezoning, which was OK with the developer, because his plan was to rent it out till it was rezoned. Right about that time, winter hit hard. A week later, I was driving by and noticed a frozen waterfall coming out the second floor. Yep, the developer had done nothing to winterize, not even turn the water off. Bye bye rental income. Two years later it all went to a landfill.
    Bump to the top.
  • arcticman
    arcticman Member, Email Confirmation Posts: 24
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    Bumping... hope someone can answer.
  • kcopp
    kcopp Member Posts: 4,448
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    Compressed air is all I use.
  • arcticman
    arcticman Member, Email Confirmation Posts: 24
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    kcopp said:

    Compressed air is all I use.

    Compressed air is what I have been using for several years too... was looking for a faster process. Maybe I over do it with compressed air because I cycle thru every fixture several times to get every drop of water out. It takes a long time to get all the water blown out of the refrigerator's water dispenser and ice maker. The other appliances would be easier with RV antifreeze as well. Unless I can confirm its safe... I'm not going to have any RV antifreeze in the boiler's domestic water heater while the boiler is running. There's ethanol in RV antifreeze and it could be a problem. Still hoping someone can confirm.