I am considering installing a water detection device on the supply side of the water heater that would shut-off the supply when it detects a leak in the pan under the water heater.
Scenario: A leak from the water heater is detected, supply water is then shut-off, all of the water in the tank leaks out.
My question is what happens when all of the water drains out and the gas is still on? Does it begin to heat a dry tank? Is there a safety device on the water heater that would prevent the gas from continually heating? This could also happen without the device if the supply is just shut-off say when you go on vacation.
I know Watts makes one that also shuts-off the gas, but others simply stop the water.
Thanks.
Replies
I think new h20 heaters have no standing pilot light therefore the gas is not an issue!
"I think new h20 heaters have no standing pilot light therefore the gas is not an issue!"That is true for (most) tankless and power vent WH. But most WH are tank type with a standing pilot..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Bill, I'm not going to disagree with you because you lnow more than I do, except, we had a new h20 heater installed and it has electronic ignition. This may be different, depending where you live?
>>we had a new h20 heater installed and it has electronic ignition. This may be different, depending where you live?Some do, some use an standing pilot which is initially lit with a spark igniter as on a gas grill because of the semi-enclosed combustion chamber Simply a matter of which model.
Remember Mary Dyer, a Christian Martyr (Thank you, Puritans) http://en.wikipedia.org/wiki/Mary_DyerMay your whole life become a response to the truth that you've always been loved, you are loved and you always will be loved" Rob Bell, Nooma, "Bullhorn"
I still believe it is depending where you live, I know in NY you can't install any device with a pilot light.
Then it isn't a "standing pilot" it is an intermittent pilot ... right? Aren't standing pilots are on 24/7/365?
"Then it isn't a "standing pilot" it is an intermittent pilot ... right? Aren't standing pilots are on 24/7/365?"Well not when it not connected to the gas lines. The pilot needs to be lite once. That is what the push button is for on the new standy pilot WH's. Because of all of the baffeling it is hard to get into the to light the pilot.But once lite it stays on until the gas is turned off or it "fails" in one way or another..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
No ... I think good ones will have elect ignition at a minimum. Just installed one myself.
>>I think new h20 heaters have no standing pilot light therefore the gas is not an issue!Except that big blue flickering ring of light that keeps trying to heat whatever is in the tank.
Remember Mary Dyer, a Christian Martyr (Thank you, Puritans) http://en.wikipedia.org/wiki/Mary_DyerMay your whole life become a response to the truth that you've always been loved, you are loved and you always will be loved" Rob Bell, Nooma, "Bullhorn"
So what's the downside of heating a dry tank?
Wasted gas. The empty tank will cool off fairly quick, so the gas will keep kicking on trying to heat water that isn't there.
If there is one of these devices that also shuts off the gas, that's the one that should be used. --------------------------------------------------------
Cheap Tools at MyToolbox.netSee some of my work at TedsCarpentry.com
A float switch.
Chuck Slive, work, build, ...better with wood
Well, if the occupants aren't going to notice the water's off for several weeks anyway, they should turn off the water heater until they need it.
It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May
how offen have yo had a leaking water heater? I myself has never had one
My parents had one about 45 years ago.
It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May
I've replaced several water heaters over the years. In my area the big, 35 - 100 gallon water heaters, about the size of a small fridge, are commonly used. They have an average life span of 7 to 10 years. That's when they start leaking and need replaced.--------------------------------------------------------
Cheap Tools at MyToolbox.netSee some of my work at TedsCarpentry.com
I'm on my third HW tank in 13 years. Blows my mind, since the one before those three lasted 20 yrs minimum, but the prob is the new tanks are steel-lined and rust out; the old ones were glass-lined and if they didn't crack, they'd last for friggin' ever. I had scrapped the old one on general principal before it leaked. Shouldn'ta done that, maybe....
Guarantee on new HW tanks here is now 5 yrs; 7 if a licensed plumber sells/installs it. That right there oughta tell ya how long the mfgrs think they're gonna last. 7 yrs + 2 days....
I've done at least two major insurance jobs (<20k$) caused by leaking HW tanks. A weekend chalet where no one's there during the week to notice the leak, it just keeps on pissing hot water on the floor until the HO shows up on Fri nite looking for a nice hot shower after his long drive up from the city. Ooops. Have a bath instead, buddy.
Usually cause for a total gut job altho we can save the ceiling sometimes, LOL....
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
.Sears here in the states have them, ibelieve up to 12 year warentee!
The tanks in my area come with a 6 or 9 year warranty. WP has an 80 gal. that has a lifetime guarantee.
Anyway, like clockwork, ride thru a subdivision 6yr & 6 months after subdivision was built and you'll see at least 2 water heaters a week at the curb, waiting on the garbage man.
Anything that sits unused for a year is toast--- Couple of repo's I bought with 1- 3 yo tanks didn't last 4 months on recommission. Acid build up is my guess.
Another problem on a tank that is still a mystery to me. I've changed a tank out 3 times in the last 12yrs. Gas for fuel in a hot attic. Copper plumbing thru out, gets daily use, Dielectric unions from the get go and I've been using dielectric flex couplings after the 1st swap out....... Maybe that's like a double negative and cancels everything out ;-)
Thanks to those of you who commented on the empty water heater post. It sounds like the best approach is to shut-off the gas as well.Regarding water heater life expectancy, here is a website which was featured in FHB and talks about getting 2-3 times the warranty period if properly maintained.http://waterheaterrescue.com/Regarding warranties, as is most things today, they are not made to last much beyond them (see also an interesting book on this, http://www.amazon.com/Made-Break-Technology-Obsolescence-America/dp/0674025725/ref=pd_bbs_sr_1?ie=UTF8&s=books&qid=1214442994&sr=8-1) There are however, some types of WH that will last longer, but at a cost. This WH has a SS tank, but runs about $3K
http://www.americanwaterheater.com/products/productDetails.aspx?ID=1052This WH has a plastic tank, although only in electric
http://www.marathonheaters.com/index.html
my mom still has the same tank when the house was built, 1972what werid about global warming and all that. If you switch from natural gas to electric, the power company will give you a free water heater. water heater used the most power in a house. and they talk about saving power, so no new power plant need building.what about these electric cars, they have to plug somewhere and use electricity, more powerplants if everybody switch. and that means more coal
Tell yer mama to keep her '72 tank till it dies. That'll likely be longer than a new one will last. For HW tanks, they really don't make 'em like they used to....
The glass tanks were the best. If you don't crack the glass by dry-firing it or bouncing it across the floor during a remod, there's damn near nothing that'll make 'em leak. I mean, it's glass: Does Not Corrode. Only thing I know of that'll eat through glass is fluoric acid, and if you've got that in yer water, you've got bigger problems than a leaky HW tank.
Glass is also non-porous, unlike most plastics. I've got a 1959 widemouth 'Scotch Plaid' Thermos¯ bottle that still keeps soup or spag or chili hot enuff to make ya blow on yer first few spoonfuls of lunch. Fifty years and still holding vaccuum.
Yes, it's tempting to go for a new tank for energy efficiency, but there are other ways to address that problem than by junking a tank which has held onto its integrity for 35 years. If it's pissing heat through worn-out insulation, wrap it in a WH blanket or pull out the old insulation and foam it.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
I take strong exception to your statement:
Glass is also non-porous, unlike most plastics. I've got a 1959 widemouth 'Scotch Plaid' Thermos¯ bottle that still keeps soup or spag or chili hot enuff to make ya blow on yer first few spoonfuls of lunch. Fifty years and still holding vaccuum.
1959 was a very good year, but it ain't 50 years ago.
I'm still a young pup, ain't I?
1959 to 2008 = 49 years. Margin of error = 2%.
50 years is close enough.
JimNever underestimate the value of a sharp pencil or good light.
If you were born in '59, yeah, yer a young pup. My baby brother is 3 years older than you.
If you don't like my (ahem) 49-y-o Thermos, here are some '73 models. Didja carry one of these to junior high...?
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Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
I thought of several snappy comebacks, but I was taught to respect my elders.
no comment
That's right, sonny. Respect and a nickle will get ya on the subway.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
yes sir.
Hey can you tell me about the pilgrims someday? were they nice to you?
Glass doesn't corrode in water? I used to think so too- that only strong base and HF would dissolve glass. The truth is that glasses DO slowly dissolve in water- very, very slowly unless the water is alkaline, but not so slowly that they will last forever. Strongly alkaline solutions can and do etch glass quickly. Gauge glasses on boilers can corrode by 10 mils per year under the right conditions.
The glass lining in a water heater is enamel- powder sprayed on and baked to form a coating. The water heater vessel itself isn't designed such that you get a continuous, durable and holiday-free coating on all the wetted parts- if it were, it would cost more than you would likely want to pay. So there will be weak spots in the coating and you will get failures eventually. Far more durable than a galvanized or uncoated tank though.
Corrosion depends on exposure duration and intensity. You can't really compare your thermos bottle to a water heater from a corrosion perspective. A water heater is hot all the time, and has large volumes of water flowing through it over time such that the corrosion products can be taken away and fresh corrodents are supplied. I doubt you've had more than a few thousand litres through your thermos bottle in its entire life, whereas the average water heater does tens of thousands of litres per year.
You are quite right. I really like my soup with lunch, but eating 40 Imperial gallons of it per day might be a little over the top.
Talked to my plumbing guys about this the other day, too. About the new tanks not lasting as long as the old ones. He told me to pick up a new tank--which I did with only minimal grunting...and then try to hoist a 29-year-old one his boys had just changed out for a client. I could hardly get it off the ground.
'Full of mud?' I asked.
'Nope. We flushed it good before we pulled it outta there or we'd never have got it up the stairs from the basement.'
'So why's it so heavy?'
'The tank's enameled cast iron. Cast here, too; not in China. The new ones are welded up outta rolled steel made from recycled Hyundais.'
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
I something unusual recently and didn't know what it wasThe hot water heater had copper connected to the drain valve The copper was then connected into the regular plumbing going to the faucetsI later found out the reason for this and was wondering if you guys know the purpose?Sorry to the OP for the thread drift
That's a hot water recirculating system. May be gravity based, or there may be a pump.
It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May
You are correctThe owner of said water heater is concerned with the natural gas bill and is going to have the recirculation system removedIt will be interesting to see how much of an impact this has on the monthly bill
"he owner of said water heater is concerned with the natural gas bill and is going to have the recirculation system removed"
The last house I lived in had one. During the AC season I just closed a valve to shut it off. I couldn't see having it circulating warm water through the house when the AC was on.
But it was sure nice during the winter....
John Kruk: "I'm not an athlete. I'm a professional baseball player."
There may be no need to remove a recirc. system ... just shut off the pump. I have one in my house ... operated by a switch ... I turn it on a minute prior to taking a shower to minimize water run time to heat it up. Only use it when I need it and shut it of the rest of the time to minimize energy use.
Well, if the occupants aren't going to notice the water's off for several weeks anyway, they should turn off the water heater until they need it.
They could be away on vacation and didn't think to turn off eh water heater, or maybe didn't turn it off because somebody would be house sitting. Or in the case of rental units or a rented house. I could think of more scenarios. --------------------------------------------------------
Cheap Tools at MyToolbox.netSee some of my work at TedsCarpentry.com
Don't WH's all have some kind of limiter switch to prevent overheating?
The all have a thermostat to set the desired level of heat. When it reaches that temp it's stops heating. The issue is if the water all leaks out and a leak sensor switch shuts off the water, so the tank goes empty, the empty tank will quickly cool down. Then the water heater thinks it's time to heat the water again, then again, and again... but there is no water.
In short, the thermostat is the limiter switch. But I could be wrong. I'm no expert on water heaters. Just saying what makes sense to me. For the reason stated above, a leak detector switch that shut's off the water supply should also shut off the gas supply. That's all I'm sayin.--------------------------------------------------------
Cheap Tools at MyToolbox.netSee some of my work at TedsCarpentry.com
KA-BOOM
Why? How?
It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May
Another name for a water heater is 'boiler.' There are many, many cases of boilers, for whatever reasons, running dry ... with catastrophic results.
OK, maybe they weren't completely dry. Maybe the water level just got low. Maybe they were dry, and water was introduced. There's always a 'maybe.' A small amount of water hitting an hot plate can flash onto steam - and that steam will be expanding a lot faster than a small leak will ever vent. Under these circumstances, even the T&P valve may not be able to react fast enough. With that tiny leak proving that there is a weak spot in the vessel already, the stage is set.
That's why boilers have all manner of controls, most of which are safety features to keep this from happening. Nor should we let the smaller size of a 'water heater' fool us. The codes distinguish between the two solely on the size of the burner. Even a tiny 20 gallon under-sink unit is capable of soaring hundreds of feet when it goes off. My advice is ... never allow for the slightest possibility of any water heater 'dry firing.'
If the water heater leaks enough to trip the auto water shutoff then there's a significant hole. Even if someone foolishly turns the water back on into the empty tank, there's not enough heat content in the heat exchanger to create an explosive condition, especially with the leak. Explosive conditions require prolonged heating.What's more significant to me is the 40 gallons of water that's presumably leaked out onto the floor. If the OP is so worried about water heater leaks he should turn off the damn thing, and the water as well.
It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May
What's more significant to me is the 40 gallons of water that's presumably leaked out onto the floor. If the OP is so worried about water heater leaks he should turn off the damn thing, and the water as well.Can't argue with that.
The device is a good idea!
Water heater leaks most often due to rust from inside. The rusted section is first porous and you get a weep and a wet patch on the floor. If this not detected then it will become a major problem. But once the pressure if off, because of your detector, the damage is small. With a pan you should catch the "weep" spill. Still have to empty the tank for replacement.
gtmtx
Locate the water heater in a location where if it leaks no harm will be done.. Drain pan with a water trap for example or in my case mine are in the basement near a floor drain..
I asked Randy from Water Heater Rescue website about this and he replied:
That is dangerous. Whatever water is left in the tank will turn to steam rapidly and the heater could blow up. We've heard of these auto shutoff devices and are wary of them because of the possibilities for improper installation or failure.
You can check out his most excellent website at:
http://www.waterheaterrescue.com/
"Water Heater, What Happens if one leaks"
Things tend to get wet.
Politics: the blind insulting the blind.
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