Wood boiler power outage protection

[jimdavidson]

My wool boiler overheated last winter resulting in a costly mess. I have just installed a small circulator (45 watts) on the hot water loop of the furnace to take the hot water to a dump zone of about 80 feet of copper fin tube located in the ceiling of my wood shed next to the furnace room in the event of another power outage. I am hoping someone can give me some direction regarding a UPS system (uninterrupted power supply) to run that small circulator for about 5 hours or so ( I am just guessing that this is the amount of time needed)
I called a company that sells them and the fellow suggested a "sine inverter/charger" by Kisae for about $400 which would require a 12 volt deep cycle battery (100 amp hour) which would be about $180. Not sure if these are appropriate suggestions - and it is getting much more expensive that I had hoped. Would really appreciate any suggestions. my phone is 207-323-5858 and I live in Brooks, Maine.
Thank you
Jim

 

[Bad LP]

What wood boiler are you using?

From all that I've read the powerless dump zone should be gravity fed. Hot water supply to the top and cold water return from the bottom. Obviously the arrangement needs to be higher than the wood boiler and the zone valve should be normally open with no power applied.

I'm building mine this weekend using 32 feet of 3/4 BB and will pitch it slightly to aid in circulation. In my case it's all for (hopefully) nothing as I have a standby generator system.

I agree this project is costing a bit more than I thought but I'm balls deep into now. When LP returns to stupid $$$ again I'll be happy.

 

[jimdavidson]

I have a boiler from Europe I bought from some guy at the Bangor Home show about 10 years ago - It is an Atmos. it is outside in a shed and pipes underground to a large tank in the house. I have installed about 80 feet to fin tube higher than the boiler in an adjoining wood shed and contemplated doing gravity but a guy told be I should do the UPS system - now that I have the circulator in it maybe that was a mistake. Not sure how much flow/heat dissipation the gravity method would create
and i agree about the $ now that fuel oil is so cheap

 

[Bad LP]

I'm no help then. I have an indoor unit because I was not getting dressed to load a boiler outside being a bit north of you.

Love driving route 7 down to Searsport.

 

[maple1]

Ideally the dump zone should be right above the boiler, so it can naturally convect when the power goes out. With a n/o zone valve in the loop that opens on power loss. The dump zone should also be able to dump, when the power is on but the boiler overheats for some reason (damper sticks?). That in turn means also tieing the n/o zone valve to an aquastat that would break-on-rise to open the valve, and maybe also start a circ pump (likely the boiler circ/loading unit) at the same time. And then for even more redundancy, you could also run that circ through a UPS.

I have all of that - my upstairs zones are plumbed to dump to. I found a 2200va UPS, used, on Kijiji - think I got lucky there. Practically new, and it will run my Grundfoss 15-58 equipped loading unit until the fire dies. Not sure for how long exactly, since I haven't had to run it for a full load, but I think it will do 3-4 hours. It's an older unit still with original batteries - and it is big and heavy. Like, 150 lbs with batteries. I don't keep it plugged in all the time, only when I am going out while burning - as it has a cooling fan inside that is on all the time the UPS is plugged in, rather annoying since it is mounted from my floor joists right under the TV room upstairs. If your unit is outside in a shed, maybe a couple deep cell batteries tied to an inverter/charger? Not recommended inside because of off-gassing while charging/cycling - might have to be careful of that in a shed too.

I think I would scrounge up as much finned radiation as I could fit into the space above your boiler in the shed and add that. Even with my dump zone arrangement, it is borderline on whether it can dump enough heat just by convection if I have a power outage in full burn - these things generate, and hold, a lot of heat in full burn. Although, mine doesn't slow down when the power goes out since it is natural draft with the draft door wide open all the time.

Most of these Euro boilers were designed to dump heat differently - with a coil inside that is plumbed to a fresh cold water supply that would open on overheat & dump water through it, to a drain. That's what mine has, but I didn't use it - I went the 'traditional' way for here. Bottom line - when it comes to overheat protection, redundancy is VERY important.

 

[salecker]

With my storage it acts as the dump zone.
We have had a few power outages once right after i had filled the burn chamber.
The laws of thermodynamics keep the heat headed to storage,and without power the Econoburn acts like the demand for heat is over and the air to the boiler is shut off.

 

[Fred61]

I have several feet of fintube that I'll let go of for at a good price.

 

[Bad LP]

I have several feet of fintube that I'll let go of for at a good price.

Now you tell us after I just bought 32 feet of brand new 3/4. LOL. My original plan was to use what I had in the house while converting those areas to panels. Budget had other ideas... panels have to wait a little while.

 

[Fred61]

That's good ol Fred. Day late and a dollar short.

 

[jimdavidson]

Ideally the dump zone should be right above the boiler, so it can naturally convect when the power goes out. With a n/o zone valve in the loop that opens on power loss. The dump zone should also be able to dump, when the power is on but the boiler overheats for some reason (damper sticks?). That in turn means also tieing the n/o zone valve to an aquastat that would break-on-rise to open the valve, and maybe also start a circ pump (likely the boiler circ/loading unit) at the same time. And then for even more redundancy, you could also run that circ through a UPS.

I have all of that - my upstairs zones are plumbed to dump to. I found a 2200va UPS, used, on Kijiji - think I got lucky there. Practically new, and it will run my Grundfoss 15-58 equipped loading unit until the fire dies. Not sure for how long exactly, since I haven't had to run it for a full load, but I think it will do 3-4 hours. It's an older unit still with original batteries - and it is big and heavy. Like, 150 lbs with batteries. I don't keep it plugged in all the time, only when I am going out while burning - as it has a cooling fan inside that is on all the time the UPS is plugged in, rather annoying since it is mounted from my floor joists right under the TV room upstairs. If your unit is outside in a shed, maybe a couple deep cell batteries tied to an inverter/charger? Not recommended inside because of off-gassing while charging/cycling - might have to be careful of that in a shed too.

I think I would scrounge up as much finned radiation as I could fit into the space above your boiler in the shed and add that. Even with my dump zone arrangement, it is borderline on whether it can dump enough heat just by convection if I have a power outage in full burn - these things generate, and hold, a lot of heat in full burn. Although, mine doesn't slow down when the power goes out since it is natural draft with the draft door wide open all the time.

Most of these Euro boilers were designed to dump heat differently - with a coil inside that is plumbed to a fresh cold water supply that would open on overheat & dump water through it, to a drain. That's what mine has, but I didn't use it - I went the 'traditional' way for here. Bottom line - when it comes to overheat protection, redundancy is VERY important.

This is very helpful. Lots of good ideas here. Thank you very much

 

[jimdavidson]

This is excellent. Lots of good information here. Thank you very much

 

[maple1]

One more add - for whatever circ would be pumping in a power outage, you might check out a newer ECM circ as they use much less power. Like a Gundfoss Alpha. That's what I have on my house zones - don't think it ever goes more than 20w. Would have to make sure it will flow what you need it to flow though. And you should also semi-regularly exercise whatever circ you have for that if it is a circ that would be used only for that. My loading unit circ stuck up summer before last - I had to free it up with a screwdriver when I started burning in the fall. Not an uncommon occurance and definitely not something you'd want to happen when you really need it to circ. That's where redundancy comes in.

 

[jimdavidson]

Thank you - really appreciate it

 

[Fred61]

Jim
Pardon me but I get easily confused. Looking at the description of your set-up you stated that your cooling loop was in your woodshed next to your boiler room. Does that mean your woodshed is heated space?

 

[jimdavidson]

Hi Fred

The wood shed is an unheated space adjacent to the boiler room. Both are outdoors. The fin tubes are in the roof rafters above the wood and it is piped into the boiler room

 

[Fred61]

So the pipes are dry otherwise they would freeze, right?

 

[jimdavidson]

Hi Fred

I have antifreeze in them and in the rest of the system

 

[Fred61]

Got it!

 

[jimdavidson]

I have installed an inverter/charger with a deep cycle battery in my wood furnace room- now I find out that this system outputs AC power even when the electricity is on. I was wanting something that only had AC output when the power was off - as my 44 watt circulator dumps heat into a shed that is unheated and would waste heat when the power is on. I thought that was what a UPS system does. Evidently this has a UPS but power goes all the time. Is there a simple device I can plug into the output power source on inverter/charger that will prevent the power from going to the circulator when the power is on but allow the inverter charger to provide power when the power goes out - I have tied up a good deal of money in a system that does not do what I thought it did. Painful lesson.

 

[maple1]

You could perhaps use an aquastat or temp controller that has a normally closed function, and also has a function that will close on temp rise ('make on rise') - then it could also stop power to your pump when boiler temps are low (pump doesn't need to run if it doesn't have to). But that is likely over complicating things. A simple relay should work? Wiring the pump to the load contacts that are open when the coil is powered (NC contacts) ? And just wire the coil to a power source that loses power when the power goes out.

EDIT: But, that won't help you if you want that pump to run in an overheat situation while the power is on. It would work if the ONLY time you want that pump to be running, is any and every time the power goes out.

 

[Fred61]

Jim,
When you purchased your inverter/charger you missed one small item. You needed a switching inverter. I had one hooked up before I had my back-up generator installed. In fact I still have it, You can get around your problem by installing a relay that will actuate when the power drops out. Just hook it up to a normally open relay and you're set to go.

 

[jimdavidson]

Jim,
When you purchased your inverter/charger you missed one small item. You needed a switching inverter. I had one hooked up before I had my back-up generator installed. In fact I still have it, You can get around your problem by installing a relay that will actuate when the power drops out. Just hook it up to a normally open relay and you're set to go.

 

[jimdavidson]

you guys are brilliant -- I am such a novice at this stuff. You know more than the people at the place I bought the inverter/charger. I will try to get these suggestions into my brain and get the parts.

thank you so much for all your suggestions.

 

[Fred61]

you guys are brilliant -- I am such a novice at this stuff. You know more than the people at the place I bought the inverter/charger. I will try to get these suggestions into my brain and get the parts.

thank you so much for all your suggestions.

Return it. You spent too much money to get something that doesn't do the job. Of course that's the world we live in right now. They sell you an empty bag then you have to fill it at your expense. Primary example is your modern day pickup. You pay 35k for them and before you can load it up you need to buy a bed liner.

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[Fred61]

Just thought about this. Is this a pure sine wave inverter? If not, it may not run your circ. If it does, you won't like the sound. It definitely won't run the controller.

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