Boiler Thermostat - Setting on COLD Nights

[Mike.O]

Admins... Please move if not in the right location. Nothing seemed to fit, so I put this here...

My house has a few "suspect" locations where baseboard heating pipes go under/over a few doors. Also the back of my house is built out 2' over the first floor, so I have a few more feet of pipe that is in "suspect" locations. I get a little nervous that in these locations the pipes are too close to drafts or outside temps.

On cold nights the stove (Pacific Energy Summit) will have the house at 72* at bedtime and it will drop down to around 65* upon wake up.

What does everyone do with their boiler on cold nights? I would obviously like to have it on a little as possible. In a perfect world, I could get a thermostat that could kick on every 1.5 - 2 hours for 15 minutes, so 4 - 5, 15 minute cycles a night. This would circulate the water and heat the pipes up and not run it all night.

If I pick a middle setting on the boiler thermostat, say 68, then the first half of the night it's inactive, and the second half of the night its cranking away unnecessarily.

I'm sure others play this game of trying to find a happy balance... what do you all do??

Also, is there such a thermostat that you can program as many on/off cycles as you want? So far I have only come up with a 7 day programmable that has 2 on/off cycles per day. Also, the Nest does not seem to fit the bill..

 

[peakbagger]

If you do some searching on this site you will find a device that runs runs the circulators on a timer independent of the thermostat. Its intended to keep the pipes from freezing in cold spots. If you are handy its not rocket science to build one.

 

[orlkc]

I had that exact scenario happen last year, and installed a couple ThermGuards: http://www.bearmountaindesign.com/

They've worked so far, though we haven't had a really cold snap to test.

 

[Mike.O]

I had that exact scenario happen last year, and installed a couple ThermGuards: http://www.bearmountaindesign.com/

They've worked so far, though we haven't had a really cold snap to test.

Wow! That is EXACTLY what I was looking for! I'm reading around on their website now and I think I will buy one.

So the original thermostat works as normal? So if the stove goes down for a day or two there is no issues using the boiler?

 

[kennyp2339]

My primary heat is from the woodstove, I also have hot water baseboard as my back up, most of my baseboards are on the perimeter of the house; I typically don't worry about my baseboard pipes until the temps dip into the lower teens / single digits. When that occurs I just circulate them 10min in the morning, 10 min in the evening, other then that I don't really worry to much about it.
I do have to say your ahead of the game for thinking about it, most people dismiss there central heating system until they need it or something goes wrong. I remember a few years back we were in a bad cold snap and lots of people in the northeast had frozen pipe issues because they forgot to circulate there baseboards.

 

[Big Fire]

My primary heat is from the woodstove, I also have hot water baseboard as my back up, most of my baseboards are on the perimeter of the house; I typically don't worry about my baseboard pipes until the temps dip into the lower teens / single digits. When that occurs I just circulate them 10min in the morning, 10 min in the evening, other then that I don't really worry to much about it.
I do have to say your ahead of the game for thinking about it, most people dismiss there central heating system until they need it or something goes wrong. I remember a few years back we were in a bad cold snap and lots of people in the northeast had frozen pipe issues because they forgot to circulate there baseboards.

Just fix two of my pipes that froze I going to put antifreeze in to keep them from freezing then u never need to worry


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[Mike.O]

My primary heat is from the woodstove, I also have hot water baseboard as my back up, most of my baseboards are on the perimeter of the house; I typically don't worry about my baseboard pipes until the temps dip into the lower teens / single digits. When that occurs I just circulate them 10min in the morning, 10 min in the evening, other then that I don't really worry to much about it.
I do have to say your ahead of the game for thinking about it, most people dismiss there central heating system until they need it or something goes wrong. I remember a few years back we were in a bad cold snap and lots of people in the northeast had frozen pipe issues because they forgot to circulate there baseboards.

I agree. I would most likely be safe with a few manual circulations each day. We are in the north east but we weren't full time wood burners at the time when that nasty cold spell hit, so we were okay.

I do tend to over think things and it sucks sleeping like crap on the nights when it gets cold worrying about it. Something like posted above is exactly what I had in mind and had no clue they made something like that.

I learned the hard way from my parents as a kid. We had a pipe in our family room go under the back door, which was on an old attached garage floor slab, so the pipe was in a chipped out channel. Every winter, we would worry about it freezing and trying to be magicians with the thermostat to not use too much oil but have the furnace kick on enough. A few years ago, my dad finally just cut the damn run of pipe out and just runs wood in there now. I don't have a situation that bad in my house, but I do have a few sections over/under doors that make me nervous.

 

[peakbagger]

Just fix two of my pipes that froze I going to put antifreeze in to keep them from freezing then u never need to worry


Sent from my XT1080 using Tapatalk

Switching to antifreeze adds some complication and expense to the system. The recommended antifreeze is not cheap and the automatic water makeup has to be far more complex to ensure that antifreeze can not get back into the water system. Generally antifreeze is used when the system may be shut down completely for periods of time like in a winter cottage. Makes a lot more sense to me just to circulate the water occasionally when its cold and then figure out a way to warm up the cold spots in the pipes.

 

[Mike.O]

Just fix two of my pipes that froze I going to put antifreeze in to keep them from freezing then u never need to worry


Sent from my XT1080 using Tapatalk

I considered that so I asked my furnace tech about it when I had the furnace cleaned in the fall. He said that the anti-freeze is horrible on the heating system and pipes. Also he said it only has a useful life of 5 years. Not sure the truth to this but seem like he would have no reason to lie if he sells/installs the product and is telling me not to use it.

 

[orlkc]

Wow! That is EXACTLY what I was looking for! I'm reading around on their website now and I think I will buy one.

So the original thermostat works as normal? So if the stove goes down for a day or two there is no issues using the boiler?

Yes, the original thermostat (nest in my case) works as normal. I put them in the basement right at the transformer/relay, and just turn them on for the season once it starts getting much below freezing. I set the intervals pretty short since in my setup any domestic hot water cuts power to the heating zones, and thus resets the ThermGuards counter, and I don't know how often that happens at night.

 

[kennyp2339]

I considered that so I asked my furnace tech about it when I had the furnace cleaned in the fall. He said that the anti-freeze is horrible on the heating system and pipes. Also he said it only has a useful life of 5 years. Not sure the truth to this but seem like he would have no reason to lie if he sells/installs the product and is telling me not to use it.

I use to do boiler maintenance / installs and I agree that anti-freeze is a pain and if you have hard water issues to begin with it adds to an already complicated problem (mainly clogging the expansion tank bleeder) As far as leaking back into the potable water lines, it shouldn't since its code (at least around here) to have a back flow preventer in-line with the automatic water fill, I suppose problems can occur though when you run higher line pressures, the standard pressure should be 15psi. I myself had a head scratcher experience last spring, I came home to a big puddle in the basement, the pressure relief valve kicked open on the boiler, took some time to trouble shoot, I drained the excessive pressure out then waited, sure enough a few hours later the pressure kicked back up over 30psi and was climbing. I turned the automatic water fill off (gate valve) and drained the system down, a few hours later it crept back up, so I then turned off the indirect hot water heater supply off, pressure build up stopped. Turns out the coil inside the hot water tank developed a pin hole and the house water lines over pressured the system and it bleed into the boiler loop causing the pressure buildup. Up there it goes, I went on a rant again.

 

[Rearscreen]

say 68, then the first half of the night it's inactive, and the second half of the night its cranking away unnecessarily.

Not sure what you mean by unnecessarily. It's keeping your house warm and kicks on when the wood stove drops during the night. I assume, if you turned it to 55 you would wake up to a much colder house? I am imagining if I were in your situation what I would do. First I'd find the loop that has the potential freezing problem. Then I'd buy some sort of short burst timer (that will take some research). Hook that to the circulator control board parallel to the t-stat. Just enough time to move the water away from the cold area and replace it with warmer. That said, it doesn't take much time for water to freeze and if your aim is to keep the boiler from going on and off so much you would turn down the thermostat. Then you have a colder house and more of a chance to possibly freeze.
Now all this said, a better place to ask this question is in a site called The Wall heating and cooling site by Dan Holohan.

 

[Bad LP]

Anti freeze systems suck. I manage 3 of them and wouldn't own one myself. Ever.

 

[Mike.O]

Not sure what you mean by unnecessarily. It's keeping your house warm and kicks on when the wood stove drops during the night. I assume, if you turned it to 55 you would wake up to a much colder house? I am imagining if I were in your situation what I would do. First I'd find the loop that has the potential freezing problem. Then I'd buy some sort of short burst timer (that will take some research). Hook that to the circulator control board parallel to the t-stat. Just enough time to move the water away from the cold area and replace it with warmer. That said, it doesn't take much time for water to freeze and if your aim is to keep the boiler from going on and off so much you would turn down the thermostat. Then you have a colder house and more of a chance to possibly freeze.
Now all this said, a better place to ask this question is in a site called The Wall heating and cooling site by Dan Holohan.

In a perfect world, when the stove is on (24/7, unless I'm out of town, which is rare) the furnace would never come on. Regardless of the house temps. My high/low thermometer in the living room for the year reads a low of 61.7 and a high of 77.8. I am content anywhere within that range. I do not need my furnace trying to maintain 68 if the stove can't. If I wake up to 60 on a cold morning, it doesn't bother me one bit. Stuff the stove, and we're off to the races.

And yes the thermostat is set on 55 (Well actually 57 ) so that the thing doesn't turn on.

My aim is not to keep the boiler from going on and off so much, it is to go on just enough to circulate water in the pipes on the very cold nights, say less than 20*. I'm not looking to gain any heat from these cycles. The stove can handle 100% of the heating demands.

 

[Big Fire]

In a perfect world, when the stove is on (24/7, unless I'm out of town, which is rare) the furnace would never come on. Regardless of the house temps. My high/low thermometer in the living room for the year reads a low of 61.7 and a high of 77.8. I am content anywhere within that range. I do not need my furnace trying to maintain 68 if the stove can't. If I wake up to 60 on a cold morning, it doesn't bother me one bit. Stuff the stove, and we're off to the races.

And yes the thermostat is set on 55 (Well actually 57 ) so that the thing doesn't turn on.

My aim is not to keep the boiler from going on and off so much, it is to go on just enough to circulate water in the pipes on the very cold nights, say less than 20*. I'm not looking to gain any heat from these cycles. The stove can handle 100% of the heating demands.

Im told as long as u get the mix strong enough to prevent alge from growing you will be fine


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[peakbagger]

Heating systems are a compromise between complexity and cost. With an injection loop and appropriate controls you can run ECM pumps at a slow speed continuously to a very close setpoint. The radiant folks tend to go that route. Add in a thermal storage tank and you can cut the furnace cycling way down. Now add in a coil from a wood boiler into the storage tank and set up the furnace to only come on when the wood boiler isn't putting out enough heat and you are getting into a very nice system but the front end cost is high.

I have Honeywell pro grade setback thermostats that have built in brains to deal with setback periods. I just set the time in the AM they go off setback and the themostat looks at the prior operation on how long it took to heat up the room and clicks the heat on at whatever time it thinks it needs to go on to meet the time limit. Worked pretty well with my oil boiler but not so well with my storage as the available temp from the tank varies too much. I could put an injection loop in to have the storage supply constant temp but that would screw up my controls.

I keep getting tempted to redo my system and controls but I effectively heat for free between wood and surplus PV generation to my minisplit so I have no way of justifying the cost.

 

[yooper08]

What temp does the house cool off to when it's a "cold night" when you worry about it? Say it's 62, set the thermostat at that instead. That way, at the end of the burn, the boiler kicks in for a little bit, and then when you get the stove going, it just takes over. No need for fancy gadgetry, just set it at a fail safe temperature. It won't call for heat on a normal day this way.

 

[Mike.O]

What temp does the house cool off to when it's a "cold night" when you worry about it? Say it's 62, set the thermostat at that instead. That way, at the end of the burn, the boiler kicks in for a little bit, and then when you get the stove going, it just takes over. No need for fancy gadgetry, just set it at a fail safe temperature. It won't call for heat on a normal day this way.

I don't think inside temperature has much to do with me worrying about anything. I have a few "suspect locations of piping that run in cantilevered sections over the back of my house. These pipes are in a 12" bay that has nothing but cold air below. No significant heat from the inside of my house is getting into these bays. If it is 10 degrees outside, regardless of inside temp, these pipes are likely to freeze if there is no circulation in the heating system.

What I currently do is turn the furnace on to a temp warmer than the stove can keep. So if I think my stove can hold the house at 64 on a cold night, my thermostat is at 66 or 67. So from say 1:00 on, the furnace is carrying 100% of the load. I don't need or want this. If I guess a lower temp and set the thermostat to 64 or 65, I gamble that the furnace will never kick on and my pipes are stagnant all night. I'm trying to avoid this guessing game and have the furnace on as little as possible.

 

[Mike.O]

Yes, the original thermostat (nest in my case) works as normal. I put them in the basement right at the transformer/relay, and just turn them on for the season once it starts getting much below freezing. I set the intervals pretty short since in my setup any domestic hot water cuts power to the heating zones, and thus resets the ThermGuards counter, and I don't know how often that happens at night.

Just ordered one! Says its should be here in 3 days. Just in time for this weekends cold spell. Very much looking forward to using this.

 

[yooper08]

I don't think inside temperature has much to do with me worrying about anything. I have a few "suspect locations of piping that run in cantilevered sections over the back of my house. These pipes are in a 12" bay that has nothing but cold air below. No significant heat from the inside of my house is getting into these bays. If it is 10 degrees outside, regardless of inside temp, these pipes are likely to freeze if there is no circulation in the heating system.

What I currently do is turn the furnace on to a temp warmer than the stove can keep. So if I think my stove can hold the house at 64 on a cold night, my thermostat is at 66 or 67. So from say 1:00 on, the furnace is carrying 100% of the load. I don't need or want this. If I guess a lower temp and set the thermostat to 64 or 65, I gamble that the furnace will never kick on and my pipes are stagnant all night. I'm trying to avoid this guessing game and have the furnace on as little as possible.

Agree the device gives more predictability for when the pipes circulate. That said, you're achieving almost the same thing by lowering the temperature from 66 to something like 62 or 64. Sure the boiler is carrying 100% of the heat load, but that doesn't mean the boiler is on 100% nor are the pipes circulating 100% of that time, at least I assume the thermostat isn't calling for heat the entire night.

An minimum indoor temp of 55 is generally recommended to keep pipes from freezing. Also, where air is leaking in are the spots to really be worried about.

Have the same thing as you though, the whole back side of the house has the soffit/overhang with certain areas containing hyrdonic heating pipes. Caulked the entire run one summer.

 

[firefighterjake]

What I do . . .

Normal Winter temps in the past . . . thermostats are set at 60 degrees. Normally the oil boiler does not come on unless a) it's quite cold outside (teens or below) or b) I did not load the stove right before bed or went to bed early. In which case . . . normally I hear the water trickling through the system and it wakes me up in time to restart the fire.

That said . . . this year I have sequestered one of our cats upstairs in a bedroom all to herself as she is getting ornery and doesn't get along so well with the other cats. I have her room thermostat set to 65 degrees. Since the door is closed, not allowing heat to come into the room as easily, I find the boiler kicks on a little more often than it did in the past.

If temps are forecast to be sub-zero . . . To keep the pipes from freezing -- both the piping with the oil boiler and domestic hot water -- I'll crank up the thermostats two or three times a day for a while to move heated water through the pipes. I figure the movement of water and moving heat through the pipes will keep things from freezing up.

In 10 years the only times I have had issues with frozen pipes has been with a) a pipe to my kitchen sink that ran close to an outside wall without insulation and b) an outside spigot that I forgot to shut off inside. Both were easily fixed with a hair dryer and prevented in the future with insulation/chaulk and just being a bit smarter.