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  1. Hunderliggur

    Hunderliggur Minister of Fire

    Joined:
    Dec 23, 2009
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    602
    Loc:
    Lothian, MD
    Ever wonder what happens to 1 1/4 PEX when you have a hurricane and run out of backup power when the boiler is running? When the pressure valve pops the water will vaporize somewhere in the piping. ImageUploadedByTapatalk1352314911.944934.jpg

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  2. avc8130

    avc8130 Minister of Fire

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    God's Gift to Gassification
    How did that happen? Don't you have a gravity fed over-temp dump zone?
  3. 711mhw

    711mhw Feeling the Heat

    Joined:
    Dec 7, 2010
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    402
    Loc:
    Western ME
    Thats a pretty dramatic failure there! I quess you can't blame the pex. Hope no one was in the way, and you got your juice back.
  4. Hunderliggur

    Hunderliggur Minister of Fire

    Joined:
    Dec 23, 2009
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    602
    Loc:
    Lothian, MD
    A dump zone is probably a good addition, I'll have to see what sizing I'll need. Even with backup power if the pump failed it would be the same problem. The PEX is all in conduit underground. The pile failed about 2 feet from the copper in a 12 conduit through the foundation. I was able to work in a copper replacement. This was in a 6 inch conduit. ImageUploadedByTapatalk1352334522.077745.jpg
  5. maple1

    maple1 Minister of Fire

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    Nova Scotia
    Ummm...

    Wow.... :eek:
  6. BoilerMan

    BoilerMan Minister of Fire

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    Northern Maine
    Glad no one was hurt, and that's some carnage there! I'd keep that near the boiler to remind you the power of hot water.

    TS
    711mhw likes this.
  7. goosegunner

    goosegunner Minister of Fire

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    A gravity dump zone is for a no power situation. It should be sized for your boiler.

    A parallel pump with own sensor would help if a pump failed.

    Glad no one was hurt and you got it back together.

    gg
  8. Mauler

    Mauler Member

    Joined:
    Jun 19, 2008
    Messages:
    46
    Loc:
    Southern New York
    I had the same thing happen with this hurricane. Overheat, boiled thru the pex on my outdoor econoburn. Luckily it wasn't underground tho. No dump zone. If its an outdoor boiler where do you put a dump zone?
  9. goosegunner

    goosegunner Minister of Fire

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    WI

    How about installing a Battery back up with pump where your outdoor lines come into the house. Once the fan stops on the boiler if you are moving water I would think it would help. You could also divert the water through a dump zone in the house with a normally open valve. Maintaining the battery backup would be the key.

    gg
  10. maple1

    maple1 Minister of Fire

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    What does the manufacturer recommend? I think any boiler manual I've read covers overheat protection in some way - think it would be a big liability if they didn't. One quick thought is to have a relief valve on the boiler and a fresh supply somewhere in the system that would let cool supply water in to make up for what gets blown out the relief valve. (But then if you have a water pump & your power goes out that might not work the best).

    Which then makes me ask - did either of these cases have a relief valve in place? And did it blow off?
  11. Hunderliggur

    Hunderliggur Minister of Fire

    Joined:
    Dec 23, 2009
    Messages:
    602
    Loc:
    Lothian, MD
    I have the cold water makeup and the pressure relief valve. By the time the valve pops the water is over 212f and will boil when the pressure is released.

    I like the idea of a power failure/pump failure circulator. It could have its own backup power supply (deep cycle battery with trickle charger). A simple control system (aqua stat over set temp, say 200F; no primary voltage ->turn on circulator).

    I am also considering an over temp release valve at 212 and use my cold water make up, but that only works if we have power for the well.

    I don't think I have enough room in my boiler shed for the dump zone to work. The concept works if the boiler is in the house but not if the dump can freeze.


    I hope others can learn from my experience.
  12. Mauler

    Mauler Member

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    Loc:
    Southern New York
    they ask for a dump zone, but I didn't probe them about it, as I didnt really think I could do it outside. I have relief and cold supply but I can't tell if the valve blew (those relief valves reset themselves automatically right?) as the pex melted right next to where the relief valve dumps, by the time I killed the fire, cut the water off, and got to dissassemble the skin on the outdoor econoburn, the whole area was soaked and steaming. My installer thinks the pex melted before the relief valve could blow because the pex looked melted not blown from pressure. Not sure tho.
  13. Mauler

    Mauler Member

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    Loc:
    Southern New York
    I think keeping the water moving would help (not sure how much tho). I dont have storage, only a 60 gallon water heater that could absorb some of the heat, Do you think that would be effective? I'd guess that I really would need the dump zone, and I'm not sure how even that would help without power. I'm not clear about how a "gravity" driven dump zone works and so I'm not sure its doable with my setup. I'd love to hear some any ideas because as it stands I've got it back in operation and dont want to have it happen again.

    In my naive mind I was thinking without power the blower would just shut down and so would the fire, as it does in normal operation. I guess I was wrong. Do these downdraft burners have a damper that wont close during power outage thereby allowing O2 to keep feeding the fire?
  14. Hunderliggur

    Hunderliggur Minister of Fire

    Joined:
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    Loc:
    Lothian, MD
    In my case my boiler goes to idle at 195F. The circulator is still running the 185F +/- storage return through the boiler. There still is a lot of energy in the coal bed. When the electrical power was lost the heat radiated at the boiler (and probably down the copper). The water in the boiler jacket probably boiled, the pressure valve release, then the rest of the pressurized very hot >212F water boiled and blew out the now overheated and very pliable PEX. Then of course, the make up water went through the gaping hole and eventually though the basement wall on to the floor. Good thing my make up water is flow restricted to 12PSI since my well system can pump 30GPM at 60PSI through a farm faucet. The water in the basement was less than one shop vac tank.
  15. maple1

    maple1 Minister of Fire

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    Gravity dump zones are pretty simple but there are basic requirements. You need some radiation that is above the boiler, and a normally open zone valve plumbed between the radiation & top of boiler. Wire the zone valve up (usually 24v, you might need a 110/24 transfromer if you don't already have one) - the power keeps it closed, when you lose power it opens & water circulates. I'm not sure how that would be done in an outdoor situation. Is your boiler in an enclosure or outbuilding, or is it right out in the wide open outdoors? If it is an outside boiler & is designed for that, the manufacturer should have something specd - my thoughts anyway.
  16. goosegunner

    goosegunner Minister of Fire

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    Storage will absorb a tremendous amount of energy if you can keep the water moving. Without it, I think a dump zone in the house would be critical. Battery back up pump, and a large cast iron radiator or fin tube would probably require the least energy to run.

    gg
  17. b33p3r

    b33p3r Feeling the Heat

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    NE Pa
    I have an Econoburn in an outside shed. I have 4 8' lengths of baseboard piped across the ceiling with a normally open valve wired in as mentioned above. My max temp on boiler is set to 195. My boiler to this point has never overheated due to outages. The shed is insulated so even during prolonged outages I've never had a problem with water freezing. I actually keep a small container of water in shed during outages so I can keep an eye on whether it is freezing or not. If temps are down real low during outage I will often warm the shed back up with a kerosene heater.
  18. flyingcow

    flyingcow Minister of Fire

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    2,319
    Loc:
    northern-half of maine

    I have basically the same thing. I think it's recommended to have at least 10% of boiler out put, in your overheat loop. It's an automag valve, power closed. Power out, opens and works like a charm. I actually tripped the breaker feeding my boiler room sand watched to see if it would work as designed. It did. This was when the boiler was at max temp and at a full wide open burn
  19. BoilerMan

    BoilerMan Minister of Fire

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    I still don't know how you'd do it w/o a backup power source on and outdoor boiler. If it were in a boiler shed, or a besement install gravity flow is cake.

    TS
  20. Hunderliggur

    Hunderliggur Minister of Fire

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    Loc:
    Lothian, MD
    Finned baseboard on my ceiling could work without freezing in the outbuilding. I'll have to see where I can tap in. I am assuming the the high point of the boiler output and return after the circulator on the return.
  21. BoilerMan

    BoilerMan Minister of Fire

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    Yes, you have the right idea. Just get the finned copper element of the baseboard, parrellel up three or four of them and t into the supply and return. Use a 120V magnetic NO zone valve wired into the AC supply to the boiler, when the power fails the ZV will go into default open and allow gravity to flow up to the finned copper and the cooled water to sink down to the boiler return, it's that simple! As long as you don't think it'll freeze, this is dependent on if you have glycol in the system and/or some type of backup heat in the boiler shed.

    TS

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