Back-up power

[Reggie Dunlap]

Has anyone used a system like this?

http://www.stovesentry.com/

I'm looking for an cheaper alternative to an automatic generator to run my circulator pumps when the power goes out. The way my boiler is set up I only have a small loop that can gravity feed. If I could run 8 circulators and the draft fan for a few hours the fire will die down to where it won't overheat the boiler.

Probably someone with a little electrical ability could build something like this with an inverter but I'm just a lowly carpenter.

Thanks,
Reggie

 

[BrownianHeatingTech]

Computer UPS systems are pretty cheap, these days. That's what I've been using. I can assemble something a bit cheaper from components, but this way it's fully warrantied and all in one nice unit for the homeowner to deal with.

Joe

 

[Moose]

how long could you run circulator pumps on a computer ups?

 

[heaterman]

Moose

That would depend on the actual wattage draw of your circ(s) and combustion fan. Figure that up and then you can shop for a UPS with that output. The wattage or amperage should be listed on the circ and the combustion fan motor. If it gives amperage use (voltage x amps) to arrive at actual watts of power.

Example: 120volts x .85 amps = 102 watts

 

[Moose]

Ok I realize my question was kinda vague I didn't have the numbers on me. I wouldn't want to do anything but run my circ pumps to my dumping areas. I have quite a bit of radiant floor heating in the house so I'm pretty sure not positive that will keep my system cool enough. now I just have coils running though my fire box if the radiant heat couldn't keep the water cool enough I should be able to install a shut a valve off before the wood boiler and after the wood boiler then open my pressure relief valve and allow the water/pressure to drain out right?

 

[Tony H]

I might be off base but this is the way I understand this situation...

If you are home I would think you could just shut the temp control down and have the boiler idle and choke the fire down until power comes back up.
When you are gone the problem would be the fire would cook and the water would not circulate so the boiler could overheat if the controller does not shut it down

I was planning to use a small UPS to connect the boiler and pump so they would run for a couple of hours. If you look up the amps or watts you can go to a web site like APC and run it thru the calculator with the time you want and they will tell you the models that will fit the application.
The way I understand it all you would really need to power is the boiler so that the controller will idle the unit when the water hits 175 or whatever the setting is and will not fire it back up until it gets down to 140 or whateven the low temp setting is. I just figured for my application since I only will be running one pump to start I might as well size it for that as well and then I can still have heat.

 

[BrownianHeatingTech]

Typically, I don't power the boiler on the UPS. By killing power to the boiler, it will let the fire die.

The UPS powers a pump for the basement zone, which is connected directly to the wood boiler. The pump can be triggered by either the thermostat in the basement, or the over-temp aquastat on the boiler.

So, in a power failure, the boiler shuts down, and the UPS makes power available to the pump. If the boiler temp spikes over the overtemp limit (typically 205 degrees), the pump comes on and starts dumping heat into the basement, next to the boiler.

Joe

 

[Reggie Dunlap]

What's a UPS?

 

[Grover59]

In my case I have a dump zone that has a zone valve that fails open on power outage, this just lets the boiler water themo siphon to the baseboard in the house, I may also put in a UPS for the circulator to the oil fired boiler to keep that going on power out, as long as that circulator is running the boiler will not over heat, there will be no power to the blower for the fire.

Steve

 

[BrownianHeatingTech]

What's a UPS?

Un-interruptible Power Supply

Basically, a battery complete with charger and inverter, all in one box. They are used for computers, so you can keep working if the power goes out. Most computer places (eg, Best Buy) have them.

Joe

 

[Moose]

I'm new to the wood boiler aspect of heating, so if this was already covered extensivly my appoligies. I guess I don't have a true " Boiler" in the sence, but I have a wood stove with water coils on the inside of the fire box. So I get heat off the stove which I plan on housing and running through my forced air system. and the coils I plan on plumbing into my existing oil boiler to heat my dhw and dump the extra if any to my radiant floor heat and forced air heat exchanger in order to keep the system cool. So I don't have any combustion fans or anything like what you would have in a gasification boiler it is just a basic stove with coils in it. My hope is in the event of a power outage is to just run the circ pumps and hopefully it will keep the system cool, and in the event that it does not I would like to install the valves on either side of the wood stove that would shut the flow of water to the boiler off and open the relief valve to relieve any pressure build up in the wood stove, and just utilize the heat off the fire box to rise from the basement to the rest of the house. So in the event that everything that I have stated is possible and "safe" what would be the best or most common way to safely circulate the water in the event of a power outage. Here is an upside down picture of the inside of the firebox.

 

[Eric Johnson]

Neat pic, Moose. Thanks for posting that. Is this the view when looking into the firebox through the loading door? That's some pretty clean innards compared to the boilers I'm used to.

Your strategy sounds pretty good. You need to keep the water circulating at all times to avoid overheating the water in the coil. As long as it's moving to some sort of radiant device like the baseboards you mention, it should work fine.

But isolating the water flow with valves is a bad idea. Even with no pumps running, the water will tend to circulate away from the stove as it heats, which it's going to continue doing if there are coals or wood in the firebox. And the rest of your system provides some pressure relief as well. So the last thing you want to do is restrict the movement of the water in those pipes. If you do, it will eventually boil and if you're lucky, lift the pressure relief valve. If the valve fails (happens), the thing can and will blow up. I'd consider putting two pressure relief valves on it, just in case. They only cost around $15, and could well save you a lot more than that. Make sure you get the ones for boilers, which are set at 30 psi--not the much higher pressure units used in water heaters. They look similar and both have 3/4-inch threads, so it's not hard to mix them up.

I don't know about Ogdensburg, but the power supplies in most of the North Country have never been particularly reliable, especially in the winter with trees falling on the lines and ice storms playing havoc with the grid. Depending on how fancy you want to get, you could locate a cast iron radiator above the stove (say in a room directly above it), and then pipe it into the stove piping so that you can open a valve and let the water naturally circulate into the radiator in the event of a power outage. All you need is a radiator, a couple of 3/4-inch ball valves and some 3/4-inch pipe. Better yet, you can get an Automag zone valve, which opens when the power is cut. That way your stove will automatically dump its heat even when you're not around (or asleep).

 

[Moose]

Yeah the things almost 30yrs old but only has one season to burn time to it so its basicly brand new. All the dump sites are above the boiler and I hope that it witll naturally push the hot water to them. When I was talking about isolating the system I was thinking of installing a thermostat to where if It couldn't keep the water cool enough and it started over heating it would isolate the the coils you see and then open a valve and just allow it to vent there for no pressure. This way maybe I could still run the stove and when the power turned back on I could let the stove cool and the plumbing cool and reintroduce the water back in to the coils. what do you think? It does have a 30psi relief valve but like you said I don't like to rely on them.

 

[Eric Johnson]

So basically, you want to isolate the coils and dump the water in them to avoid the risk of it boiling in the tubes. You're right--that would solve the problem, but it might make a mess. Make sure those tubes are designed to be run empty. With a regular boiler, the last thing you want to do is drain off the water, because that's what protects the steel around the firebox. And you will have to drain the water out of the tubes--not just open the pressure relief valve. In my view, they should either be full of water or empty. It's a safety issue.

I'd say offhand that if all your dump zones are above the stove, the water should naturally convect enough to keep the thing from overheating. Easy enough to test--just kill the power to the pump and see what happens.

 

[Moose]

ok sounds good Eric. That solves one of my list donno's thanks. I have to install the chimney and the block and tackle should be arriving this week to lower the beast into the basement. I'll take lots of pics and keep them posted. Especially of all my mistakes. Oh and there will be plenty.

 

[Eric Johnson]

Around here, we like to call that "experience." I'm going to spend my weekend in the tank, trying to get it all hooked up and hopefully running before it gets really cold, which it's supposed to do next week. Maybe we'll get some decent snow out of the deal, too. If I was closer, I'd come up and give you a hand.

 

[Moose]

Well I've been watchin your little tank project. Thats what really got me interested in heat storage. I hope to one day to get a gassification boiler and build a house arround it and a tank. But in the mean time I think I have enough learning experiances to keep me busy. And I just got rid of engough snow to be able to he my truck back in the woods to get a load of wood. Just moved here in sept so I'm a little behind the woood curve here this year. Its killing me I still have had to leave like 4 full cords behind in ohio. gave most of it away but I still have atleast 1 full cord in the shed dry as can be.

 

[Eric Johnson]

I hear you. Last time we moved, I'm like: "What do you need all that furniture for, honey? Dump that anoir and I'll have room for another half cord of wood in the Ryder truck."

 

[wdc1160]

Another thing you may want to consider in your parameters is that the numbers you normally see associated with "sizing" of UPSes are VA or Voltage Amps. Which is say -- .85 A X 120 V = Watts.

A watt is not a VA. If you want to find what a VA is Google it or (broken link removed)

Long story short my rule of thumb is VA X .6 = Num of Watts for 10 minutes.

That works for most normal Wattage. To small or to big and it no longer applies.

Also these "PC" based power supplies are not best suited for outdoor temps when we need them. I work with this often, infact lately very often and can tell you this is far from their designed purpose. they do have such ups'es they are more expensive.

I have dismissed this as an option for my combo system since duration is relatively short.

 

[Moose]

Well what would be the Ideal battery back up system that you could leave plugged in to keep it fully charged? Maybee a deep cycle marine battery with an 120v ac converter with charger? or 2?

 

[wdc1160]

Well, Yes, in my opinion.

that is how Reggie started off, but we got turned towards APC's line of UPS's.

Which I do have experience with. I just wanted to throw a word of caution to be aware that
they had a specific design focus. Straying from the focus will undoubtedly change their functionality.

This was Reggies Idea

Has anyone used a system like this?

http://www.stovesentry.com/

I’m looking for an cheaper alternative to an automatic generator to run my circulator pumps when the power goes out. The way my boiler is set up I only have a small loop that can gravity feed. If I could run 8 circulators and the draft fan for a few hours the fire will die down to where it won’t overheat the boiler.

Probably someone with a little electrical ability could build something like this with an inverter but I’m just a lowly carpenter.

Thanks,
Reggie

 

[Reggie Dunlap]

After looking into the battery back-up it looks like a $5-600 dollar project by the time you get a battery or two. That's a lot of money considering it's only going to be able to run one or two pumps for a few hours. For comparison you can buy a Guardian 7KW generator with an automatic transfer switch for $1900 and run 8 circuits including heat and water.

The generator costs four times as much but the capability to power half the house is tempting.

Reggie

 

[Bartman]

You don't have to invest even that much for a generator, you can buy a portable, minimum of 3500W (that will give you 120/240V) and install a manual transfer system. There are a couple of options you can go with depending on what your main panel is. Lately, when I sell a service change, or panel replacement, 85% of my customers opt for back-up generating capability with a 120/240V, 30A power inlet on the side of the house to plug their generator into. The Guardians and Briggs & Stratton units are nice, but pricey.

 

[wdc1160]

Jesus Reggie,


7 kw Go big or go home huh?? I really like that line of generator, and especially the fuel choice. This is what I did.


My design had 3 factors in mind.
What will I power with it.
How long will I need it? If needed.
And, finally make it cost under $500 dollars.
Batteries didn’t fit the bill.


I determined I needed this only in the winter .
I only need to power
3 1/6 hp circs @ 125 watts EA
2 needed for heat storage water to water exchange
1 for the house
1 contoller board almost nothing
1 1/8 hp induction fan @100

I can kill the power to the heat storage stuff very easily. That 250 watts eliminated.

I choose a 1.5 Kw generator (gas)

I figured in case of an ice storm I was going to be one of the first grids they brought back, since I am on the grid with a Wal-Mart.

I figured I needed 24 hours.

I choose gas as a fuel since I always could get my hands on enough gas to power 1 KW for 24 hrs. However, I guarantee at my house I could get 72 hrs worth of gas without siphoning off of my vehicles.

On the flip side we all know that gasoline is really a poor choice for generating with. I just leave it empty and run it dry if I need to use it. This was the obvious down side with my choice of generators. But, I paid $100 dollars. As for longevity—I will let you know.


I got some of my ideas from these guys
http://www.candlepowerforums.com/vb/showthread.php?t=176316

Maybe you have different requirements, but I hope this helps.

Bill

 

[Reggie Dunlap]

7 KW is the smallest propane generator I could find. To me, having an automatic transfer switch seems important. A 3500 kw portable gas generator would run what I need but it wont start automatically if I'm not home.