Power Outage Safety Zone, Hand Fed Boiler

hotblast1357 · Post by **hotblast1357** » Sun. Sep. 27, 2015 9:36 pm

So I have approximately 60 feet of finned baseboard without the sheet metal, I plan on mounting it too the ceiling of my basement where the boiler is, it is wide open by the way.. And using a zone valve, that is normally open to control it. So boiler is running, 90,000 BTU newyorker, I loose electricity, my circulator stops, but now the zone valve opens allowing gravity flow to take place in the baseboard, I have read that baseboard is good for 400-600 BTU's per foot, but I'm thinking that's with a pump, any idea what I can expect without a pump? My expansion tank is over sized so I'm not worried about hitting the 30psi limit on my prv, but I have pex going to my modine and furnace coil, so I do not want the temps getting too hot in the Pex, the baseboard loop would be directly off the feed line of the boiler, before air scoop and expansion tank and manifold, and the return would be on a drain port in the rear, also bypassing the return manifold where the Pex is.

Thoughts/comments/concerns?

hotblast1357 · Post by **hotblast1357** » Sun. Sep. 27, 2015 9:41 pm

Zone valve I had in mind.

http://www.supplyhouse.com/Taco-V075T2A2ZB024Q4A1 ... n-Threaded

pine grove coal user · Post by **pine grove coal user** » Sun. Sep. 27, 2015 9:49 pm

Does the zone valve open partially or fully when the power is off?
Does your air close off immediately? That is important too.
I would simulate a power failure and watch it. If the temperature spikes up, then turn the power on and go to "Plan B".

With my Tarm with the Samson controller I was surprised with how well the dump zone (first floor radiators) handled it. It was no problem at all.

hotblast1357 · Post by **hotblast1357** » Sun. Sep. 27, 2015 9:55 pm

pine grove coal user wrote:Does the zone valve open partially or fully when the power is off?
Does your air close off immediately? That is important too.
I would simulate a power failure and watch it. If the temperature spikes up, then turn the power on and go to "Plan B".

With my Tarm with the Samson controller I was surprised with how well the dump zone (first floor radiators) handled it. It was no problem at all.

Idk how far that zone valve opens. I have not purchased it yet.
The newyorker has a combustion fan so no the air does not get closed off, but there is not much air entering naturally.

McGiever · Post by **McGiever** » Mon. Sep. 28, 2015 4:45 pm

You may be just fine with having open fin-tube, but generally fin-tube gives up more heat with sheet metal covers on due to the "chimney effect" of air currents from within the sheetmetal covers.
Although with suffient footage of "open" fin-tube one can expect to "dump" all the heat they would need to.

Thermosyphon flow rate success will be determined by how large of pipe diameters used as well as the total number of bends in the flow circuit.
Big pipes and minimal bends is the key to success here...do you feel lucky?

hotblast1357 · Post by **hotblast1357** » Mon. Sep. 28, 2015 6:21 pm

haha no I never feel lucky! I will be going with 3/4" piping because that is what the baseboard is, there will not be that many 90's, I do not know exactly yet, but under 10, at least.

hotblast1357 · Post by **hotblast1357** » Sat. Oct. 10, 2015 7:08 am

i have town domestic water so I have water when electricity is loss, I could also loose it if there was a event that was bad enough I guess, but it rarely happens, could I use a normally open valve like this, and run a domestic hot water line to a drain in the basement, and put a nozzle on the end and when I loose power the solenoid opens letting the coil in my boiler keep it cool.

http://www.amazon.com/Solid-Electric-Solenoid-Val ... n+solenoid

McGiever · Post by **McGiever** » Sat. Oct. 10, 2015 7:30 am

That nozzel would be bad, it will plug up.
Drill a good sized hole in a pipe cap, maybe???

lsayre · Post by **lsayre** » Sat. Oct. 10, 2015 7:47 am

If your boiler is fan or blower induced you may find that your boiler has no need for a dump zone during a power outage. Off the top of my head you would need to hit roughly 250 F° to also hit 30 PSI and open your pressure relief valve.

I'm aware of at least one boiler owner on this forum who has no dump zone at all, but rather uses sufficient expansion tank capacity and a knowledge that his boiler does not hit 250 degrees before it begins radiating away as much heat through its surface as the coal (which under no electrical power will not be induced to produce heat via a fan or a blower) can produce under nothing but chimney draft, and then turns the corner and cools down.

Post by **Rob R.** » Sat. Oct. 10, 2015 7:49 am

Your idea about the N.O. zone valve and fin tube is good, but as McGeiver said it is tough to tell how much heat those elements will give off without the enclosure. If you have a room in the house that could use some extra heat, you may want to consider a length of high output baseboard for that room. That way you would have the benefit of an extra zone in the house, and also be able to use it for your power-loss dump zone. Slant Fin Multipak 80 would put out ~900 BTU's per foot.

hotblast1357 · Post by **hotblast1357** » Sat. Oct. 10, 2015 8:04 am

McGiever wrote:That nozzel would be bad, it will plug up.
Drill a good sized hole in a pipe cap, maybe???

ok I can look into that.

hotblast1357 · Post by **hotblast1357** » Sat. Oct. 10, 2015 8:08 am

lsayre wrote:If your boiler is fan or blower induced you may find that your boiler has no need for a dump zone during a power outage. Off the top of my head you would need to hit roughly 250 F° to also hit 30 PSI and open your pressure relief valve.

I'm aware of at least one boiler owner on this forum who has no dump zone at all, but rather uses sufficient expansion tank capacity and a knowledge that his boiler does not hit 250 degrees before it begins radiating away as much heat through its surface as the coal (which under no electrical power will not be induced to produce heat via a fan or a blower) can produce under nothing but chimney draft, and then turns the corner and cools down.

well larry that would be fine with me if I didnt have pex in my system, it is thermoysphoning all the time so I do not want 220 degree water flowing through the system. my pressure is at 8 psi at room temp so it would take a long time to hit the 30 psi mark, this is just a fail safe, id rather know that it wont get over 210, I will have to find out how many BTU's a gallon of water takes to heat up, and then I can make the dhw nozzle flow that to keep the boiler stable.

hotblast1357 · Post by **hotblast1357** » Sat. Oct. 10, 2015 8:11 am

Rob R. wrote:Your idea about the N.O. zone valve and fin tube is good, but as McGeiver said it is tough to tell how much heat those elements will give off without the enclosure. If you have a room in the house that could use some extra heat, you may want to consider a length of high output baseboard for that room. That way you would have the benefit of an extra zone in the house, and also be able to use it for your power-loss dump zone. Slant Fin Multipak 80 would put out ~900 BTU's per foot.

well rob it was a good idea, but after reading about zone valves I am worried that not using the valve except for rare occasions may cause it to stick and then not operate when I need, so I would have to plum that zone in copper or black iron though correct so it will thermosyphon?

Post by **Rob R.** » Sat. Oct. 10, 2015 8:21 am

Why not just put it on a thermostat and use it?

The slope of the piping and height of radiator compared to the boiler is what allows it to thermosyphon.

hotblast1357 · Post by **hotblast1357** » Sat. Oct. 10, 2015 8:27 am

lol I could, so I would have to put a pump in, which I have a spare 007, but then I would need a check valve right? I don't want ghost flow when the grundfos runs to heat the exchangers? but with a check valve it wont flow without electricity? and I cant pipe this in pex correct?

Power Outage Safety Zone, Hand Fed Boiler

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