Myth Busters- Exploding Water Heater

lee_7

anything can happen if murphy's around

Gary Reecher

Anyone else see what Adam and Jamie did with a water heater? Removed the safties then direct wired an electric hot water heater. Now if that did not convince you not to plug the relief valve and mess with safties this what they did next. Took a second water heater, but this time they built a very small house to California code. Think the salmon colored paint job was overboard but needless to say there wasn't any part of that house still standing after their demo.

Unknown

I think,

most of us did, but in case you missed-it, I found it here.

Dave

lee_7

i remember as a kid a weater heater going up thru the roof of a 2 story colonial in my home town and landing in the front lawn. The relief valve had been leak and then stopped. They thought all was well, but relief had plugged shut. luckily no one was hurt, except house. it had to be torn down due to damage.

Mark_46

Holy Crap

Much like a bomb. Safety first!

In order for this to happen the relief valve must be stuck, or non existant, with continued heat input where the tank has made set point temp but the heat source continues/wonn't shut off. Both of these conditions are unlikely, agree?

Anna Conda

Disagree, particularly on the first condition. Ask anybody here how many times they've seen a T&P valve connection capped off, with no T&P valve in sight, and they'll run out of toes to count on. The second condition is less likely, but does occur. All it takes is one Murphy day.

greg a

Hi guys:I'm a firefighter in CT.Just wondering if that could happen to a boiler with a defective T&P,or would the seals or gaskets blow ahead of time.

Thanks Greg

John_173

boiler explosions

Greg -
check out Boiler Explosions in the Library under Resources.

Unknown

Here`s a story,

an employee of mine said years ago when they were kids, they used to play in this abandoned house that had an old boiler in the basement. Anyway, they figured they could build a fire in-it, but they had to plug all the openings first,,,they did and proceeded to build this fire, after awhile when they were getting warm and toasty it exploded!!
One of the guys lost an eye,,the other part of his ear. Go-figure!
TRUE STORY!!

Dave

Anna Conda

Boilers go kaboom real good and real easy - that's why they have T&P relief valves on them, to try to bleed off the pressure before the jacket fails. The most common causes of boiler explosions are the combination of a) failed LWCO and b) failed relief valves. Neglect is the most common cause of those safety failures.

Unknown

Hey Anna Conda,

Have not seen you here in awhile,,how has the steam train thing been going?

Dave

Anna Conda

Oh I'm always here, I just lurk like a snake in the grass *grin* 6060 had a good run this season, pulling six trips. She looked lovely with her fresh paint job and had no breakdowns this year; last year she developed a cylinder leak but the repairs held up splendidly. She did hit a cow this year but the cow walked away with only minor injuries; 6060 herself sustained not even a scratch I had the pleasure of introducing a couple of friends to 6060. Such a joy to see their eyes come a-glow at the power of her. Thanks for asking! Here's a pic of the grand lady herself (no not me, 6060)

http://i16.photobucket.com/albums/b19/artemis_666/6060 August 07/2007-08-21013.jpg

Mitch_4

here is the aftermath

greg a

Ouch I guess So. Our crew went on a reported water leak call a while ago,when we went into the basement,the boiler was rumbling and groaning real bad.I could tell the T&P didn't let go.I told my LT that we need to get out and get out now.We shut the emergency switch on the way out,told everone inside to get out, and just let the boiler cool off for a couple of hours.I was always wondering if boilers could take off like awater heater.Thanks for the info guys.

Greg

Unknown

greg a

That`s one reason why the drip line from the RV is NOT SUPPOSED TO BE THREADED as people can screw a cap on-it!
SCARY STUFF!

Dave

kev

never

Use black pipe nipples or fittings on drip tube. I have seen a few that became plugged solid from steady dripping.

Gary Reecher

Not so. Adam and Jamie stated that there have been two cases of unintentional exploding water heaters in the past few years. One was in Minnesota went through first, second floors and the roof.

Darrell

Got a call i almost put off until tomorrow on the way back from Ninilchik...two hours down the road. Boiler makng a funny noise. My daughter was driving and we stopped and took a look. WMC PCG-5 the pressure guage was indicating 80 pounds and the temp was over 280. I told D2, my daughter...it stands for daughter number 2, not to touch anything, punch up 911 and stand ready by the door. Yes, we had watched Myth busters the other night. After we cooled her down and got it to stop jumping up and down we discovered a stuck relief valve...wouldn't even open with a hammer. The son-in-law had fooled around with the boiler earlier tryng to get flow to an upstairs zone and turned the limit to the stops. The air vent cap was screwed down tight and the fill-trol did not fill the boiler. To its American built credit the CG took right off after I replaced the parts and not a drip showed. The GFS 15-42 even ran smooth. Its scary how close that was to alot of noise and rubble.

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ScottMP

WOW

Thats scary, working next to a bomb.

How did you cool it down ??? Time ??

Scott

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Darrell

I very gingerly loosened, but did not remove, the airvent cap, MOM #67, and let the pressure bleed off slowly while I explained the gravity of the situation to the owner and her son-in-law. You could hear it whistle outside! With that much pressure and steam...if the relief had opened or something else failed catastrophically at that point would have been a disaster with nowhere to hide. Even if the fill valve had suddenly decided to work...

The neighbors on both sides of the house have called today for complete inspections as have the son-in-law and his mom! The son-in-law was wondering if I was going to report this to the State Troopers! I guess I got my message across to them.

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G Averill_2

When I was just starting in the business, my boss gave me a copy of the Watts Regulator film that shows what can occur when a relief valve is sealed.
I was shocked then to see the damage, which seems very fresh in my memory today.
I use this many times in 'hydronics 101' training for our staff hoping they can also remember what pressure can do to a pressure vessel.

jp_2

don't mean to 2nd guess but....

Isn't slowly reducing pressure extremely dangerous?

if the boiler is over 212F and pressurized, water stays liquid, if you reduce the pressure that over temp waters going to want to go steam and real darn quick as in the water heater explosion.

best shut the heat off, go out to lunch and return after a ice cream sunday.

Darrell

You are correct...and that's why the whole service call took nearly two hours...it does sound kinda brief here on the wall.

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Mitch_4

I was taught

to never touch ANYTHING on a dry fired boiler...go outside and turn off the gas meter / oil tank / propane tank.

Touching anything may cause cold water to suddenly be released into the boiler.

Turn off the meter, evacuate the home, wait 3 hours...

To me, still the best way.

Mitch

Janet_4

Clip Available

Does anybody know where I can find a downloadable clip of this demonstration? The one on You Tube is flash. I'd like to pass it along to a teacher I know for classroom use.

Thanks in advance!

Al

Mitch_4

Al

go to http://www.waterheaterblast.com/


Mitch

nugs

Danger Lurks

I too thought the Mythbusters episode was fun to watch, but I'm not too sure what the myth was they were busting. The Watts Regulator Co did this demo back in the fifties and filmed it. The video is called Danger Lurks and I show it to my 1st and 2nd year plumbing classes every year. It is a much more invloved video and shows several water heaters blowing up as well as archival footage of buildings and houses destroyed. Still the mythbuster episode gets a very wide audience so for public education purposes it was a good thing.

Anna Conda

That's exactly why: To Joe Average, it's an urban myth. That's why we see so many capped-off T&P nipples. Joe Average typically has the idea that if it's in his home, it's not dangerous. I had exactly that conversation with a buddy, shortly after viewing that episode: She couldn't believe that "they" would allow something so dangerous to be put into homes (yes, I facepalmed, hello!) Kinda sad, ennit? People will believe stuff about smearing Vicks Vaporub on their feet to cure a cough, but will write off exploding pressure vessels as urban legend....

nugs

As a side issue. Years back I was on call for oil burner service and I got a no heat call about 11:00 one night. It was an apartment building and when I got there the basement was dark and poorly lit as usual so I'm creeping around with a dim flashlight trying to find the boiler. What I found was bits and pieces of the old steam boiler all over the basement floor, the chimney blown apart from the floor to the ceiling and bits of cast iron lodged in the floor joists. Seems the lwco had failed for a bit and so had the awf. I guess the awf finally decided do work and that's when all hell broke loose. Good thing nobody was hurt

Steve Ebels_3

I like that Anna

Let's call that the Vicks factor.

There really is some kind of a disconnect when it comes to believing or not believing certain things. It seems that the more bizzare something is, like smearing Vicks on your feet, the more likely it is that folks will believe it. When it comes to things that make sense however, it seems that a good share of people suffer a brain seizure of sorts and cease all cognizant thought. A classic example I recently observed was the community center board that believed the spiel of the outdoor wood boiler guy when he claimed his unit was over 90% efficient due to the flame coming out of the stack.

We should come up with a working definition for the "vicks factor".

RonWHC

Service many

units for a good customer. One of his projects has 4 boiler rooms. Had an on-site "engineer." So he only called us when he had to. Were there last week for a "not enough heat call."

Seems the engineer replaced a radiator valve. He filled the system, but couldn't figure out the control timer was in set back. Tech called & reported 80# pressure on the system. 50# boiler. Told him he was seeing things & to put his gage on the boiler drain. I was right. Only 78#. American Standard sure built them good.

The "engineer" left the bypass valve open when he finished venting the radiators. The Watts 740 poppet was rusted to the seat. The spring had rotted away. The stem was connected to nothing.

Oh yeah. We now have 4 new PM Agreements w/ Summer Services. Everyone, but the engineer, was lucky on this one.