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BOILER VALVE

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by 91LMS, Nov 12, 2012.

  1. 91LMS

    91LMS Member

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    has everyone used a normally open water valve when plumbing their system to prevent excessive pressure build up in the event of a loss in power?

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  2. 2.beans

    2.beans Minister of Fire

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    i use battery back up with an invertor
  3. 91LMS

    91LMS Member

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    i had one plumber tell me a story of an overtemp that has me freaked out. i would like to do the battery backup as well but doesnt the pressure relief valve on the boiler prevent this from happening as well?
  4. maple1

    maple1 Minister of Fire

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    I do. I suspect most others as well. Pressure relief is necessary & would help in an emergency type situation - there should also be a cool water supply that would let cool water in to take place of what blows off when the relief blows to cool the boiler. But it would all make a big mess if it did blow - and if you have an electric well pump that's something else that would get disabled when the power goes out.
  5. heaterman

    heaterman Minister of Fire

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    Ideally, you want a normally closed zone that will open and then gravity flow when power is interrupted. The zone should have enough heat emitting capacity to handle whatever is going on in the boiler. This is often very tough to do given that you need enough capacity to handle the 100% output of the boiler with a full load of wood.
    Design accordingly for the worst case scenario because that's when Mr. Murphy of Murphy's Law fame always tends to show up. :)

    Plan B could be a UPS battery backup that will handle things for a couple hours until you get the boiler shut down.

    Plan C is a well maintained generator, LP or natural gas fired with an automatic transfer switch. That gets everything back on line within about 5 seconds. At a cost of course.
  6. You mean a normally open zone valve? Or one that opens when power is lost.
  7. heaterman

    heaterman Minister of Fire

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    Opens when power is lost. .......normally open, normally closed............I'm dyslexic so I think backwards....... :)
  8. heaterman

    heaterman Minister of Fire

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    A pressure relief will dump at 30PSI which any normal boiler is rated at. The issue in a worst case is what happens after all the water has boiled off and you still have a fire going in there. Better to keep the water in the boiler and cool it somehow which of course leads to the dump zone or uninterruptable power supply of some kind.
  9. 91LMS

    91LMS Member

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    my current heating system is designed with circ pumps for the two baseboard zones in the house. if i put a normally closed valve on the zone in the basement as my dump zone will it still flow through the circ pump or would i need to take that out and redesign? or am i best off with battery/inverter backup. will the boiler gravity feed through the circ pumps? right now i would need to feed through the supply from my wood boiler to oil boiler as well as through the dump zone pump too.

    i appreciate the help, i dont want to make mistakes and have to cut this thing back apart after its filled. not sure if some pics would help?

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  10. maple1

    maple1 Minister of Fire

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    Basics: you need a circulation loop that starts off with a rise from boiler to radiation (i.e. radiation is above the boiler) then returns to the bottom of the boiler. You install an normally OPEN zone valve in the loop above the boiler (between boiler & radiation), and wire it to a 24v AC circuit (typically 24v, you might be able to get a 110v one). The only time water will flow through that loop, is when the power is cut off to the zone valve (i.e. a power outage). You could also add in an aquastat that would open the circuit (turn power off the to zone valve) in an overheat situation when the power is still on - i.e. overfiring. You may also be able to plumb in this dump/overheat loop to your existing zones, depending on your system layout - then it will dump the extra heat directly into your living space. That's what I did when I added more dump capability for my new boiler. So two key components: a normally OPEN zone valve, and a radiation loop that will flow by gravity.
  11. goosegunner

    goosegunner Minister of Fire

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    I would be interesting to know what the output of boilers are when they are have a good wood load but the fan has lost power. Moving water with a battery backup with essentially a idling fire should help prevent an overheat, especially if storage is on line to accept btus.

    gg
  12. 91LMS

    91LMS Member

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    good thing with my boiler is that i dont have a blower and the electric draft door defaults to closed in the event of power loss. now the issue that i have is that my boiler return has to climb from the oil boiler 5 feet or so out of the oil boiler, travel 60 feet horizontally and then return to wood boiler. my zones or radiant loops are the 60 feet away from the wood boiler via 1 1/4 black iron pipe so i am guessing there will need to be a circulator pump involved to make this all happen in the event of a power outage.

    back to one of my questions though, will hot water gravity feed past a non powered circ pump?
  13. maple1

    maple1 Minister of Fire

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    will hot water gravity feed past a non powered circ pump

    Yes - as long as the loop it's going through is conducive to gravity flow. In other words the pump won't stop it. It might hinder it some if there's a check valve in it. A couple of the end switches (that start the circ pump when the zone valve opens) in my zone valves have gone bad & don't work anymore. I never bothered replacing them because the zones flow OK without the pump running.

    Some people in your situation just hang some radiation (e.g. Slantfin) above their boiler & use that for a dump loop.
  14. 91LMS

    91LMS Member

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    thanks maple. i know its hard to give advice not seeing someone's system but the ideas at least get me in the right frame of mind. i just need to know that i am not painting myself into a corner with my system and i can make changes and adapt mine to cover all of my bases.
  15. maple1

    maple1 Minister of Fire

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    When plumbing your new supplies & returns, you could stick an extra T with a plug in it (or two) in both to allow for easier future additions/changes. Also lots of valves to isolate things later so you wouldn't have to drain everything to take a plug out & thread in new piping. Even better is instead of a plug, thread in a valve then put a plug in it - makes things much easier later. Even if it never gets used, you're only out the cost of a couple of valves & Ts.
  16. 91LMS

    91LMS Member

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    10-4 maple and i agree. last weekend had the threader home and went to town, sucks to be rushed but the white stuff on the ground is a reminder i dont want to burn anymore oil!!! i am going to cut in and put t's in at my boiler so that i can add a radiant near the boiler for ease of circulation given no power. i just am doubtful that with my pipe all overhead then having it travel back down to my other boiler and have to still rise again to travel back to the wood boiler it would work.
  17. maple1

    maple1 Minister of Fire

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    Your dump zone wants direct-as-possible connections to the supply & return ports of your wood boiler. So if doing a small dedicated zone of radiation just for dumping, put it over your wood boiler.
  18. 91LMS

    91LMS Member

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    exactly my plan, i have a coupling on the supply and circ on the return so i will take it apart tonight, outfit with t's and be in business. i may go to battery backup for extended outages to have heat later on but this will be a fail safe in the even i am not home. thanks a million for the help, i really appreciate it.
  19. BoilerMan

    BoilerMan Minister of Fire

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    91LMS, where are you located? If you are close I can lend a hand.

    TS

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