Going away on vacation... OWB prep

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timberframe

Member
Dec 11, 2013
48
Mid Michigan
We are going away for a couple of weeks this winter when the Michigan air temp is likely to be around 0*. When we go I will have the gas boiler take over the job of keeping the house warm. In preparation for the OWB, should I keep the pump going non stop to keep the water circulating? Will that be enough to keep the OWB and underground tubing from freezing up? thanks for your help.
 
Here in VA a constant circulating pump is enough to keep the water above freezing. That's what I do. You'll be colder there tho.

Dependingon how its plumbed some heat from the indoor boiler could backfeed out to the OWB.
 
We are going away for a couple of weeks this winter when the Michigan air temp is likely to be around 0*. When we go I will have the gas boiler take over the job of keeping the house warm. In preparation for the OWB, should I keep the pump going non stop to keep the water circulating? Will that be enough to keep the OWB and underground tubing from freezing up? thanks for your help.
If you are not going to be around the only way to guarantee you will have a usable boiler when you get back is to use antifreeze.
Worst case scenario...no power for a couple of days for whatever reason,could be a storm taking out power,or something as easy as a power blip that trips the breaker for the pump.Then your system will be done,including your underground lines if they freeze.Tough to thaw water underground when it's the beginning of winter.
 
I guess I could put some antifreeze in the system. When I get home should I drain the water and refill with clean water? Do I use rv antifreeze or auto? Is a couple of gallons enough? The system holds 250 gallons of water.
 
the easiest and cheapest option is to have someone feed your boiler, relative, friend or neighbor. you should have someone checking the house anyway, even without a boiler, as a power bump or similer can affect heating systems. damage from a frozen house can be very pricey.
 
What if I drain the water from OWB. Then disconnect the OWB water pump and bring inside. Then in basement disconnect the two water lines (feed and return) that go into the heat exchanger and blow out the lines. Would that work to temporarily winterize the system?
 
Maybe, if you get all the water out of the low spots. Sounds like a lot of work though for each time you leave, then getting it back up each time you come back (which could be tricky in zero° weather). Plus each time you drain & fill you are adding all kinds of fresh oxygen back in and losing whatever treatment might have been added.

If this was going to be a semi-regular occurance for me I think I would check out proper glycol and be done with it - for years to come.
 
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Maybe, if you get all the water out of the low spots. Sounds like a lot of work though for each time you leave, then getting it back up each time you come back (which could be tricky in zero° weather). Plus each time you drain & fill you are adding all kinds of fresh oxygen back in and losing whatever treatment might have been added.

If this was going to be a semi-regular occurance for me I think I would check out proper glycol and be done with it - for years to come.

So with Glycol, I would just add it to the OWB and make sure it circulates for a day or so, then shut the breaker off to the OWB. That would shut off power to pump also. Is that OK? Would I have to drain the whole system out when I return from vacation or just leave the Glycol in the system?
 
So with Glycol, I would just add it to the OWB and make sure it circulates for a day or so, then shut the breaker off to the OWB. That would shut off power to pump also. Is that OK? Would I have to drain the whole system out when I return from vacation or just leave the Glycol in the system?

Once you have it in, it stays there. I have no experience with it so have no idea on the 'recipe' or costs. I think it is spendy and takes up most of your boiler volume but IMO would be worth it if going away will be a regular thing. Ask around at your local OWB dealers for more details, and also hopefully more input will come here from those who are using it. I think the only other potential issue it has other than cost is it isn't quite as good at moving heat as pure water but that might be a negligible difference. But it may also have side benefits of providing boiler treatment effects - so check on that too.
 
Once you have it in, it stays there. I have no experience with it so have no idea on the 'recipe' or costs. I think it is spendy and takes up most of your boiler volume but IMO would be worth it if going away will be a regular thing. Ask around at your local OWB dealers for more details, and also hopefully more input will come here from those who are using it. I think the only other potential issue it has other than cost is it isn't quite as good at moving heat as pure water but that might be a negligible difference. But it may also have side benefits of providing boiler treatment effects - so check on that too.

Thanks for the info. Hopefully someone will chime in with more information, cost and their experience using Glycol.
 
How is it plumbed into the rest of the house? If the boiler and piping is well insulated, and it flows its water through the house (especially if it's through a forced air furnace heat exchanger), it likely will 'steal' enough heat from the house to stay above freezing (assuming the house isn't being kept super cold).

The last thing I would do it shut the pump off, however. The underground lines are likely the first place that will freeze, and good luck getting them warmed back up in the middle of winter if you can't push water through them.
 
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another option is to put a small electric heater in the firebox, stuff some insulation in the smokepipe, and leave the pump on. as stated earlier the heat exchanger in the house will add heat to the water but the pump must be left ON.
 
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Glycol takes about 10% of the efficiency away. It is costly, corrosive to joints and it must be checked annually for proper ratio.
 
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I think I will shy away from the Glycol.
Instead If I just drain the water from the OWB and then disconnect pump, shouldn't I be able to blow the water from the lines where I disconnect pump? That would involve blowing water 60 feet to house, then 20 feet inside house to exchanger and back out thru return line. Probably a total of 160'. If I blow lines from where the pump is disconnected, do I have to worry about blowing lines and putting to much pressure into heat exchanger?
 
I have a Garn in my shop with a pump before the hx. My infloor in the house has glycol and a propane boiler. I bring the Garn up to 190* turn the propane on, lower thermostat to 50* and hope for the best.
I have only gone away for 3 days in that kind of weather -30 and it worked fine. The boiler in the house sends warm water out to the shop hx at the Garn so it stays at 50* as well.
The underground line is only water as is the Garn.
Maybe not the most efficient way to do things but it works.
If the power went out for a few days I’d probably be screwed but that’s what insurance is for.
 
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If the power went out for a few days I’d probably be screwed but that’s what insurance is for.
Just make sure the insurance company dosn't have the weasel words in the fine print were they say "sorry xxxx happened and we don't cover that"
Counting on a insurance company to cover your ass isn't a guarantee now a days.
 
Just make sure the insurance company dosn't have the weasel words in the fine print were they say "sorry xxxx happened and we don't cover that"
Counting on a insurance company to cover your ass isn't a guarantee now a days.

Especially with an outdoor heating appliance. I know for a fact my HVAC company will not cover any outdoor boiler for anything even if they did the install. Says so in easy to understand language right in the contract.