How to prevent frozen pipes

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sandie

Feeling the Heat
Oct 29, 2009
279
West of Boston, MA
OK, I have a question I have turned down our furnace because we are running the woodstove a lot, so at night, I can hear the circulators running but since the furnace has not kicked on then no hot water is going through the pipes. I have upstairs thermostat at 50 and downstairs at 54. We do not live upstairs at all so just trying to keep from getting frozen pipes when it really cold out by leaving the heat go up there. SO the question is that woodstove, we are not heating the water going through the forced hot water system. I am sure we are not the first people to have the same thing but need to know what people do to keep the same thing from happening.
 
The water in the system can't/won't freeze if the house is kept above freezing. If I was really worried about it, I would just drain the system. (I will admit I am assuming it can be drained) I would be more concerned about plumbing up there. If a heater line freezes and bursts it only has so much water to leak.. unlike a toilet or sink supply..
 
The answer will depend on the house setup. But simply put, during very cold weather, don't be afraid to run the boiler or furnace a little. The oil/gas you burn up will be cheap insurance next to a potential repair bill.

You could put a remote wireless thermometer with an alarm upstairs to let you know when the temps are getting low.
 
In some older homes the supply and return lines are run in outside walls with little or no insulation to protect them.
They rely on the near constant movement of the always warm water in them to prevent freezing.

Some are gravity circulating units, others have a circulator pump.
Most systems can be drained, but are difficult at best to recharge without spending hours or more to get rid of air pockets.
Some systems can have zones or rooms turned off and disconnected from the system.
A local heating contractor could look over your system and advise.
If in doubt, run the system at a minimum.

Freshwater plumbing is an issue too, find out where it runs and how it was designed to work with the heating system to prevent freezing.
Some systems can get by with just a centrally located radiant heat system, and others rely heavily on a furnace blowing warm air through a nearby duct, or hot water circulating nearby on a regular basis.

Rob
 
here is my fix, i drained the heating system and filled it with non-tixic antifreeze. worked great. use a transfer pump to fill system, furnace guys will do it for a charge
 
CTBurner said:
here is my fix, i drained the heating system and filled it with non-tixic antifreeze. worked great. use a transfer pump to fill system, furnace guys will do it for a charge

Sounds like an obvious thing to do!

My home was originally built as a well-insulated home with electric heat. Ugh... When I bought it, I had oil heat installed, and both floors are heated by piping hot water up to heat exhangers, distributing the heat with air ductwork. This was done so we could have central AC. I asked the contractor about antifreeze in the lines, especially since lines go up into the unheated attic. He insisted that it was "fine" since they were very "careful" to keep the lined down low in the insulation. After I figured out what the oil heat was going to cost, I started to heat with wood, and during the second heating season I started to get water coming in the ceiling below the air handler. Not surprisingly, when I shut off the valves for the water lines going up to the attic and drained them, the water stopped. That was many years ago. I have not bothered to fix the heating system up there since it's not really needed. Heat rises, and it stays nice and warm up there (65- 70 deg) even if heating just with oil from the downstairs system (like if we leave for a weekend).

Anyway, I wish I had insisted on some antifreeze in those lines!!
 
Virtually every home where I live that heats with hydronic hot water (most of them), use a propylene based antifreeze in their systems. I run a 60/40 mix with water.
 
these rooms upstairs are guest rooms so need to have heat up there, before wood stove we heated with our furnace and kept the doors closed and the thermostat was inside one of the rooms. So when it goes below where we set that thermostat it calls for heat(it does not start the furnace however) but since we turn the thermostat to 50 or so when we we have wood stove on then the upstairs is cold and calls for heat but all it gets is the cold water. will the movement of the water in the pipes keep them from freezing when we are at the cold weather time? OR I can run the furnace and not have the wood stove going sometimes when really cold so we will have the hot water in the furnace so it will go upstairs when called for. We do not run the stove 24/7 so not enough heat to heat the upstairs I do not think and even so the pipes are out in the eaves so they could freeze without hot water going through up there.
 
I was a bit concerned in my first year of burning that I could end up with frozen pipes . . . I soon discovered though that while some rooms may be chillier they never dipped down to below freezing. That said, I still have a space heater on a thermostat in the room with the boiler (it's also right next to a bathroom) and on those sub-zero days or nights I'll fire up the boiler a few times to move some heated water through the pipes. I also have the thermostats set to turn on the boiler at 60 degrees . . . but the boiler rarely comes on during the winter.
 
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It's important to remember (as someone else pointed out), it isn't the room temperature that is important. It's the temperature of the water lines (whether heating or plumbing). Those lines may be on outside, uninsulated walls. The room temperature can be fine, but the lines in the outside walls can freeze.
 
OK, I have a question I have turned down our furnace because we are running the woodstove a lot, so at night, I can hear the circulators running but since the furnace has not kicked on then no hot water is going through the pipes. I have upstairs thermostat at 50 and downstairs at 54. We do not live upstairs at all so just trying to keep from getting frozen pipes when it really cold out by leaving the heat go up there. SO the question is that woodstove, we are not heating the water going through the forced hot water system. I am sure we are not the first people to have the same thing but need to know what people do to keep the same thing from happening.

I saw this was an old post, but if just as important today. Many folks in this forum are using the ThermGuard to circulate a little water through their pipes for a couple minutes every few hours when the weather gets cold. ThermGuard attaches to your thermostat in 5 minutes and is completely programmable for the wait time between circulation and the duration of the circulation. www.bearmountaindesign.com

Stay warm and keep the pipes from bursting!
John
 
Since we just got through a cold spell here with single digit temps, I was running the boiler a lot (propane). Though I didn't really need all that heat, at night I felt it important to keep it running just to prevent a freeze up (which had happened one night when I didn't have it running as much--stat set too low). What I'm thinking now (because I did use maybe 20 gals of propane over the last week or so) if it happens again (single digit temps) I might disable the firing of the boiler and just let the circulator run with cold water moving through the pipes which would also prevent a freeze up without using any fuel (besides elec to run the pump).

The only thing about doing this (am thinking of just disconnecting the ignitor wire) is what happens if when I put it back it doesn't work any more. Theoretically that shouldn't happen, but there might be another safer way to do it.

Edit: I could just turn off the gas valve to the boiler, that would serve the same purpose without messing with the electronics. It would be like running out of propane, the circulator still runs during calls for heat running the water through the baseboard radiators to prevent a freeze even though you're getting no heat from it.
 
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I had two bursts in pipes in the basement. Both over drafty windows. -12 Saturday morning. I know now not to have any air blowing over pipes. Added pipe wrap over those sections. I even had the boiler running just in case to ensure it wouldn't freeze. But my stove ran well enough that the boiler never was called to circulate.
 
I run my heater some to keep the water circulating. 30 inch stone walls, but that cold outside air comes right through.
Unfortunately hot water baseboard heat runs around all the cold outside walls. Catch 22. :)
 
I run my heater some to keep the water circulating. 30 inch stone walls, but that cold outside air comes right through.
Unfortunately hot water baseboard heat runs around all the cold outside walls. Catch 22. :)

No doubt! Sucks using oil to just keep water inside the pipes. I can't drain it cause I need to used the boiler when we are away for days at a time.
 
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It is amazing how what is perfectly adequate weatherstripping around doors when it's in the teens and twenties becomes laughably inadequate with close to 0F and the wind whipping.

And it looks like one way they make these window a/c units so inexpensive is to cut out the air sealing. The older ones are not a problem, but these new ones all need to be covered and sealed in the winter.
 
No doubt! Sucks using oil to just keep water inside the pipes. I can't drain it cause I need to used the boiler when we are away for days at a time.
I think I might look into the antifreeze deal in the system. Another great tip from Hearth forum.:)
 
Since we just got through a cold spell here with single digit temps, I was running the boiler a lot (propane). Though I didn't really need all that heat, at night I felt it important to keep it running just to prevent a freeze up (which had happened one night when I didn't have it running as much--stat set too low). What I'm thinking now (because I did use maybe 20 gals of propane over the last week or so) if it happens again (single digit temps) I might disable the firing of the boiler and just let the circulator run with cold water moving through the pipes which would also prevent a freeze up without using any fuel (besides elec to run the pump).

The only thing about doing this (am thinking of just disconnecting the ignitor wire) is what happens if when I put it back it doesn't work any more. Theoretically that shouldn't happen, but there might be another safer way to do it.

Edit: I could just turn off the gas valve to the boiler, that would serve the same purpose without messing with the electronics. It would be like running out of propane, the circulator still runs during calls for heat running the water through the baseboard radiators to prevent a freeze even though you're getting no heat from it.
Hi Dave,

I have a sample schematic that uses a ThermGuard and a 24VAC relay that disables the ignitor when the ThermGuard circulates water through the pipes. It is pretty simple and doesn't cost much. The ignitor is disrupted only when the ThermGuard is running and reconnected automatically when the boiler is running in a "normal' heating mode. relay 4 pole ignite.jpg
 
Antifreeze is expensive and will leak through places which were watertight (TRUE STORY)
Use it as a last resort IMHO.
 
The answer will depend on the house setup. But simply put, during very cold weather, don't be afraid to run the boiler or furnace a little. The oil/gas you burn up will be cheap insurance next to a potential repair bill.

You could put a remote wireless thermometer with an alarm upstairs to let you know when the temps are getting low.

This is what I had to do. This is my first year burning with the furnace shut off and never even thought about the cellar getting super cold. On the nights it was supposed to be below 0 I fired up the oil burner and let it run at 50 or so just to keep some heat in the cellar. Worked out OK so far but over the summer I"ll be getting the cellar more cold hardy.
 
Very interesting. Not completely clear how that ThermGuard device works. I have 3 thermostats and zone valves so sort of ruled out the idea of having to use three ThermGuards.

Now you seem to be suggesting you could use just one TG (and 1? additional relay). When I installed the zone valves I just followed the schematic on the taco box -- didn't really try to figure it out so not sure how this would work with them and the controller on the boiler.

Main question about the TG is do you use it manually only (i.e. turn it off and on when you need it) or is there some way to control it by sensing the outside temp/and/or can it be turned on remotely?

Okay lets assume it's manual only. I turn it on when I see the temp getting into the single digits. Will it run with the tstat (both could be on) or above the tstat -- when it's on, the tstat is overriden, or will the tstat override the TG when the tstat is calling for heat. Or prolly that doesn't really matter, when either is on all switches will be closed for the zone. Just not sure how to wire it, with the zone valves.

As far as disabling the coil, that may end up too complicated, not sure if your schematic would apply without disabling the coil. So am assuming if using one TG, you could put it near the heater and zone valves to simplify wiring, but then you'd have to go to the heater room to turn it on and off.

Was trying to look up the relay but unfortunately I'd have to key it in-- no way to copy and paste the picture -- and haven't gotten around to it yet. But more important, if there's a link to the user instructions for the TG that might be helpful.
 
Very interesting. Not completely clear how that ThermGuard device works. I have 3 thermostats and zone valves so sort of ruled out the idea of having to use three ThermGuards.

Now you seem to be suggesting you could use just one TG (and 1? additional relay). When I installed the zone valves I just followed the schematic on the taco box -- didn't really try to figure it out so not sure how this would work with them and the controller on the boiler.

Main question about the TG is do you use it manually only (i.e. turn it off and on when you need it) or is there some way to control it by sensing the outside temp/and/or can it be turned on remotely?

Okay lets assume it's manual only. I turn it on when I see the temp getting into the single digits. Will it run with the tstat (both could be on) or above the tstat -- when it's on, the tstat is overriden, or will the tstat override the TG when the tstat is calling for heat. Or prolly that doesn't really matter, when either is on all switches will be closed for the zone. Just not sure how to wire it, with the zone valves.

As far as disabling the coil, that may end up too complicated, not sure if your schematic would apply without disabling the coil. So am assuming if using one TG, you could put it near the heater and zone valves to simplify wiring, but then you'd have to go to the heater room to turn it on and off.

Was trying to look up the relay but unfortunately I'd have to key it in-- no way to copy and paste the picture -- and haven't gotten around to it yet. But more important, if there's a link to the user instructions for the TG that might be helpful.

Hi Dave,
That is correct. If you are handy, a simple connection between a ThermGuard and a relay could activate as many as 4 zones simultaneously....3 zones if you wanted to inhibit the ignitor. The idea has been floated to make the ThermGuard outside air temperature controlled, but the variations to meet everyone's needs got too cumbersome. For now, you can just turn ot off when aren't concerned about your pipes freezing.

There is non-volatile storage in the ThermGuard that remembers your programming of interval and duration. So when needed, all you have to do is turn it on and you are ready to go.

Normally, when you use one ThermGuard per thermostat, the thermostat overrides the ThermGuard. That is to say, if the thermostat calls for heat, the ThermGuard goes to sleep and doesn't start timing until the call for heat is met...or... if the thermostat is turned off, the ThermGuard overrides the thermostat and calls for heat periodically to keep the pipes from freezing.

Another question you had was the location of installation. ThermGuard can be installed in the boiler room or at the thermostat.

With regard to the coil, I was really thinking that the circuit interruption could occur on the 24VAC side, rather than the high voltage ignition side. You could basically interrupt one of the signals that is used to enable the ignition. My boiler has for instance: 1) fan proving switch 2) blowout detector 3) over temp sensor. Each of these go into a serial chain and when all are good, the ignitor starts. If you interrupt anywhere in the chain, the ignitor will be disabled and the circulator motor will run and fuel will not be burned.

Of course, if you trade off the inconvenience of interrupting the ignitor vs the small amount of fuel that would be used....say 3 minutes every couple of hours, it may not be worth it.

Here is a link to the relay
http://www.grainger.com/product/OMRON-Relay-2W932?searchQuery=2w932

Here is a link to the ThermGuard installation instructions:
http://www.bearmountaindesign.com/tg_installation_Hot_Water.htm

Here is a link to the ThermGuard programming instructions:
http://www.bearmountaindesign.com/tg_programming_hot_water.htm

This is a great discussion, thanks for your considered questions.
John
 
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Virtually every home where I live that heats with hydronic hot water (most of them), use a propylene based antifreeze in their systems. I run a 60/40 mix with water.
Anyone know about what this cost? May be cheap insurance.
 
As I think I mentioned earlier, antifreeze is a good solution for some installations, but the tradeoff is that it tends to gum up or corrode zone valves a little faster than plain water. I use it, so not saying it's a bad idea, just that it ain't no free lunch (as with most things in life).

-dan
 
just that it ain't no free lunch (as with most things in life).

-dan

Not true! ThermGuard comes with a coupon for a $5 foot long.

Kidding :)
John
 
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