econoburn 280 degree overtemp

[bowsky64x]

Last night the power went out at 2:30 , I woke up at 4:30 and went out to the shop to check the stove and walked into a room filled with steam.
Scary! the digital gauge read 280! the purge was blowing steam. I imediatly hooked it up the generator but the pump wouldn't pump in cool water from the system because the water in the boiler was boiling. I killed the fire with water and sat there for 3 hours watching the temp drop 1 degree at a time. I now have the system back up and found the only casualty was the air purge near the boiler, i replaced it and everything else seems fine. now I am unwilling to run the boiler overnight until this issue is resolved. I will buy anything that will give me peace of mind that this will never happen again. I like the idea of a battery backup but I also would install a heat dump but I want to be sure the heat dump is going to burn off the btu's. Any advise on either of these would be great. I have 6' above the stove for a heat dump but I need to be sure it will thermosipon properly. or a battery backup but I want something reliable and bulletproof that is sure to keep the unit running.
thanx

 

[Nofossil]

Search on 'automag'. It's common practice to have a thermosiphon dump zone plumbed with a zone valve that opens when power is removed.

 

[sgschwend]

I am curious as to what cases this problem.

Is this an issue due to the small boiler water capacity?

If so, how many gallons does a boiler need to hold in order to minimize the temperature overshoot?

Thanks for the info,

Steve

 

[bowsky64x]

Thanx for the automag info. I feel that a proper heat dump is my best bet. So I need a zone valve that is closed when power is on and opens when power is off. Now for the heat dump I think that some finned copper tubing would be the best. Where can I buy just the pipe without the baseboard cover? HOw much pipe do I need . I would guess i would T off the outlet of the boiler going up and install the zone valve and then run the dump up and back down to the boiler inlet. hot water rises up the pipe and cools as it enters the boiler

 

[mikeyny]

You should have at least 10% of your boilers rated output for a dump zone. Search the board here for more info on dump zones, there is a ton of it.

 

[flyingcow]

Thanx for the automag info. I feel that a proper heat dump is my best bet. So I need a zone valve that is closed when power is on and opens when power is off. Now for the heat dump I think that some finned copper tubing would be the best. Where can I buy just the pipe without the baseboard cover? HOw much pipe do I need . I would guess i would T off the outlet of the boiler going up and install the zone valve and then run the dump up and back down to the boiler inlet. hot water rises up the pipe and cools as it enters the boiler

As said, 10% of boiler output, maybe more? I found some old fin tube from a heating/plumbing company. Given to me. this was hooked up to my boiler, directly off of the supply and return of system.

 

[Singed Eyebrows]

A radiator(cast iron etc) mounted above the boiler plumbed in with 1 1/2" fittings should thermosyphen well when used with the solenoids(large enough pipe size) you mentioned. You can buy add on cooling loops possibly Zenon might have these. They were available from Kotly & now they don't ship to the USA anymore. You can see what they look like at www.kotly.com. These use a loop along with a thermal solenoid that doesn't require any elec. power & when temp goes past 200 they open & city water cooles the boiler, Randy

 

[jebatty]

In addition to the overheat loop, you need to consider air leaks in your firebox door, your forced draft inlet, and other places that will continue to feed the fire if a power loss. Also think of timing on a power loss: 1) fire in high burn and 2) boiler water temp 190F or so and boiler ready to go into idle mode. This is about the worst case for a power loss, as minimal boiler capacity to absorb more heat. Test your system in this scenario.

The more I think about the overheat loop, the more I think it would buy peace of mind to have a separate small circulator on a computer UPS just for the overheat loop. My 3/4" line to the overhead overheat loop works OK, but forcing a little hot boiler water through the loop would be even better. A small circulator takes 70W or less, and a UPS to keep this part of the emergency system in operation for even a couple of hours in an emergency doesn't need to be very big or expensive. Probably could get the UPS and the circ for quite a bit less than $200.

Regardless, test the overheat system to make sure it works.

 

[stee6043]

After doing copious amounts of research on the "worst case scenario" you describe above I settled on what I found to be the lowest cost and most easily implemented overheat protection - battery back-up. I found a used APC UPS, replaced the batteries ($70), and life is good. They are not that expensive depending on where you find them and they require no plumbing and/or system modification. This is assuming your main circ is what moves all of your system water, of course.

I'm shocked you didn't have more damage with a reading of 280....that is wicked hot. And for what it's worth you might want to consider a dry chemical fire extinguisher for the shop. Throwing water on a fire in a boiler could have been a lot worse than what it sounds like your situation was. Pumping a $15 dry chemical extinguisher into your boiler would have put the fire out and had no risk of damaging, cracking, destroying your fire box....just food for thought.

 

[flyingcow]

If you think it's needed, instead of 10%, put in 25%, and put the outside shell of the baseboard on. Just like you'd see in a house. Now you've oversized the emergency dump zone, and with the shell, it'll convect the way it should. Just set it up with an automag. This will take care of your problem. Kinda surprised this wasn't a must do, on the list of install directions. If this wasn't on your instructions, I'd recommened calling EB and suggesting this. Also system should be set up so if in an power off/overheat situation, a safety of sorts trips the power to the boiler. You have to manually reset it, after it cools off.
Now next time power goes out, go shut off the primary and secondary air, and leave. The dump zone will take care of boiler. There really is nothing else you can or should do. IMO, you got very, very lucky that the pump didn't move any water. Could have been a very nasty situation, with you going to the ER for skin grafts. No joke! Someone mentioned hooking this up to city water, so it'll cool down faster. IMO, that also is a bad idea. Both secenarios could/would have shocked the boiler. Than you would have some damage. Let the system cool down, preferably 170ish? It takes a long time for a house to cool off for any freezing damage. At least a day or two. No hurry.
BTW, i have been in an power off/overheat sitaution( 1 week ago)wothout power for 3 hours.. Right at a full burn, 2/3 loaded, pushing 195+ to the house at the time. Boiler got 230ish and it held. I may also put some more baseboard up.
You get that feeling of , geez it's getting hot, i should do something! It was stressful, but I walked away, crawled back in bed, woke up a few hours later when the power came on. Boiler cooled off, I hit the reset so i could have power back to the boiler. All is well. BUT it was hard to walk away.

 

[maplewoodshelby]

My power also went out last night and boiler got up to 240 before I could get to it. Needless to say I am now putting my dhw hookup on hold as I am putting in my backup power system consisting of inverter, relays and deep cycle batteries. That way even when power is out I can keep heat going instead of installing dump zone and losing it. I dont think there was any harm to my boiler and I feel lucky as I had coal and wood in there going

 

[Chris Hoskin]

The automag / thermo siphon set up is a standard part of our plumbing diagrams and works well as flyingcow indicates. If you can't find the right zone valve locally we have them here (valve and 24V xformer are about $150 together). Also correct that we specify 10% of boiler output; so a 100,000BTU boiler requires two 8 foot lengths of fin tube (standard baseboard is rated at 600BTU / ft output). Pretty straightforward, but you can download any of our schematics from the website for details.

More importantly, I would like to echo the thought that you have some other things to check. It would seem that for the boiler temp to creep up that high with the power out, you had to still have some air moving through the boiler. Check door gaskets and chimney draft - excessive draft will continue to pull air through the boiler even when the fan is off and is easily solved with a barometric damper on the flue pipe.

Chris

 

[flyingcow]

My power also went out last night and boiler got up to 240 before I could get to it. Needless to say I am now putting my dhw hookup on hold as I am putting in my backup power system consisting of inverter, relays and deep cycle batteries. That way even when power is out I can keep heat going instead of installing dump zone and losing it. I dont think there was any harm to my boiler and I feel lucky as I had coal and wood in there going

Everything electronic will fail at sometime. I'd still have some fintube up, hooked to an automag. Any reputable boiler should survive without a dump zone like we're talking. But not uncommon to loose power when the winds blowing hard, which will pull a mean draft on most chimneys. I, like most here have a lot of $$$'s invested(sweat equity, also) some old fin tube and an automag is a few more pennies in the whole cost of things.

 

[stee6043]

For anyone contemplating storage a good "dump zone" can be had by mounting your tanks on a rack. If your upper tank is above the boiler you have a very nice overheat zone built right in. This is the way my system is setup in addition to the battery backup...

 

[Gooserider]

Note that the dump zone setup ideas above are all good, however I would NOT trust a UPS - they have been known to fail... The other important step that should be done is a "hot test" - once the dump zone is in place, build a nice hot fire, let it get up to full burn, everything cooking, and PULL THE PLUG - so that you have everything in the system dead, just like in a real power failure - Then watch the temps - if they go down and stay down, great... If they go up to the "nervous-making" point - say over 200°F or so, mark it as a failure, and restore power, then look at what you need to do to improve performance, and repeat... Also look at the temperature of the dump zone itself - make sure it is working right....

Gooserider