Why does my water heater leak?
I work at Home Depot – Plumbing. HD sells lots of water heaters. The most common reason I hear responsible for people wanting a new heater is it: it leaks. I’ve thought about this and wonder why. A water heater is a steel tank, the only openings are the supply and return and anode rod openings on the top of the tank. It’s obvious when they are leaking. The T&P valve is obvious when it leaks, too. Other than maybe a tank seam splitting open it seems to me the the weak spot in the system is the drain valve that hardly anyone uses.
Here’s my theory: The tank, made of steel expands and contracts at one rate, and the boiler drain valve does so at another. Over time, the drain valve becomes eccentric to the hole it’s screwed into in the tank. First it seeps and then it seeps quite a bit more….. And then I see them, ready to buy another heater.
Any thoughts on this? My guess on correcting this is to just replace the boiler drain – they cost about $4. I’m going to replace my water heater within the next month or so – it leaks. When I do, I’m going to take the recip saw to it and find the leak.
Replies
Why don't you try out your theory first.
Spend $4 on a boiler drain, if it stops leaking you've 1. Proved that you were right 2. Saved the cost of a new WH 3. Saved 10 minutes and 2 sawzall blades.
Jon Blakemore
I thought most water heater tanks were glass.
Defecation eventuates.
Glass lined steel tank...
Here fishy fishy....
Hey, I'm no plumber.
I keep telling you guys - I was hired for my looks, not what I know.Q: What's the difference between the Pope and your boss?A: The Pope only expects you to kiss his ring.
With all those strikes you should be benched about now shouldn't ya...
Here fishy fishy....
See several leak due to the electric resistance heater gasket failing. Also seen chloride pitting at the bottom due to resin intrusion from softener bottles. Corrosion at the bottom of the tank due to accumulated minerals can also cause leaks. Gotta say, though, I've never seen a drain cock leak at the threads. Past the seat, sure, but not the threads. But who knows, you may be on to something. As the guy above said, swap out the drain valve and see what happens.
Depending on where you are in the country and the type of water you can get everything you mentioned.
Early demise of the annodic rod can mean the tank is attacked sooner than the warrenty implies. I have seen tanks you could poke your finger through at the leak area. Seems to be more prevalent in extremly hard water areas.
Like you, I don't think I have ever seen a boiler drain valve leak at the threads.
Dave
All the water heater drain cocks I've ever dealt with personally (one) had normal tapered pipe threads, nothing that appeared to be a seating surface.
The valve seat is mated to the valve disc. When I said 'leakage past the seat', I meant leakby thru the seat and disc. Sorry for the confusion.
I never met a tool I didn't like!
Oh. Ah. :) Well, the one I dealt with was definitely leaking out the threads, so that probably prejudiced the way I read your message.
No harm, no foul, and hopefully, no leaks either. : )
I never met a tool I didn't like!
"I work at Home Depot - Plumbing."
Sorry to here that
"HD sells lots of water heaters. The most common reason I hear responsible for people wanting a new heater is it: it leaks. I've thought about this and wonder why. A water heater is a steel tank, the only openings are the supply and return and anode rod openings on the top of the tank. It's obvious when they are leaking. The T&P valve is obvious when it leaks, too. Other than maybe a tank seam splitting open it seems to me the the weak spot in the system is the drain valve that hardly anyone uses.
Here's my theory: The tank, made of steel expands and contracts at one rate, and the boiler drain valve does so at another. Over time, the drain valve becomes eccentric to the hole it's screwed into in the tank. First it seeps and then it seeps quite a bit more..... And then I see them, ready to buy another heater".
Wait, HD is supposed to have experienced "Retired MASTER Plumbers" in every store who no doubt have seen and experienced this problem on the countless thousands of water heaters they have swapped out in their lifetimes.
Why are you coming here when you can just ask him?
Sorry, couldn't resist, but it's Friday.
OK, I'm not a plumber so....you may not be that off track. Just a guess, but over time differing rates of expansion between the liner and steel walls of the tank, combined with other local factors could hailine fracture the liner and lead to a pin-hole leak that just gets worse.
Jon
I was wondering when someone was gonna knock on that particular door.
I never met a tool I didn't like!
Nick,
Like I said, it's Friday and..........Had a power outage at work today at 7:30am (car ran into a pole, knocked it down, yada, yada, yada) so we shut the place down and everybody gets a 3 day weekend. Probably spent a little too much tome here today. So I've got the 'puter on as I work 'round the house.
Jon
Jon,
So how much did that cost you and the other guys at the office?
Jon Blakemore
"So how much did that cost you and the other guys at the office?"
Jon
I don't work in an "office" per say. We do have rooms with workstations though, that we share, for CAD/CAM/CAE stuff, so...... If I had to do a calculated guess, maybe $5K to $10K, but impossible to do any kind of damage assessment, as the facility went pitch black, and we all had to feel our way out.
I think about 5 CNC's were running so it could be a real messy situation on Monday. BTW, we are not that big a company. Only 10 guys on the shop floor.
Jon.
Jon,
I meant how much was the pool to get some guy to make the lights go out, therefore a three day weekend.
That's gotta be worth something, especially now that the weather is turning.
Jon Blakemore
"I meant how much was the pool to get some guy to make the lights go out, therefore a three day weekend"
Jon,
Ahh, now I get it.
Unfortunately, it was a crappy day here. The accident that took the utility pole out was caused in part by rain and high winds from a cold front that came through, which ultimately turned to freezing rain, then a light dusting of snow overnight.
But hey, that isn't a bad idea......though a little dangerous.
Jon
Just 5-10K?
We had a car hit a pole and had 3,000 people idle for 4 hours. Took a lot a bad things to happen in just the right sequence but....corpoarte comptuer center went down and everyone at two utility companies set idle until we figured out everthing that went wrong, including our own dumb arse mistakes. They haven't put a dollar figure to it yet, but I'll guess close to 200k.
Poop happens.
Dave
Dave,
Yeah, it's stuff like that that makes you realize how dependent we've become on computers, machinery and the power that runs them.
Jon
I thought for Lowes and HD the heaters were made by Rheem and GE?
Problem is wain that HD wants the lowest prices possible. This forces manufactures to make the water heaters with lower quality parts to keep that bottom line at the bottom! Its been mentioned here before how you can take a delta faucet from hd and bring it to a pro supply house and they look exactly the same. However the pro delta faucet which cost more has ceramic parts and the hd has plastic parts.
Yep, I work in a plant with 7000 people. The plant has two feeds from two entirely different power companies, plus, in the building next to me, two one megawatt UPS systems. But the UPS systems are just big enough to keep a skeleton support system up -- a power outage idles virtually everyone. Figure an average of $25 an hour (probably low) and it adds up. Plus the loss of some products in production, when things shut down abruptly.
Plus, the site has probably 4000 computers, and you can figure 1% of those will suffer hard drive failure due to the outage. So, 40 systems that each will cost several thousand to repair.
Water heaters leak because they rust out. The steel tank is glass-lined (plasic-lined in some newer models), and the glass cracks over time from temperature cycling. (Sediment in the tank increases the thermal stress.) Water gets through the cracks and sets up an electrolytic reaction between the steel and any copper/brass in the system. The steel is eaten away, and a hole develops.
The sacrificial anode in the unit (made of magnesium or aluminum) is intended to prevent this electrolytic erosion, but often people remove them on the theory that they are causing odors (though this is fairly rare), and often the anodes break off over time. In theory a water heater shouldn't experience electrolytic erosion failure until the anode has failed or been consumed, but theories are often wrong in practice.
Another possible cause of failure is a failed electric heating element. Often when an element fails, it will break open in one spot and allow electricity from the power line to contact the water. This can create a rather strong corrosive current. It pays to replace failed elements as soon as they fail. (Often, if a bottom element fails, it will only be noticed as a reduction in the amount of available hot water -- the heater will continue to operate. Only if the top element fails will it cease heating.)
The newer plastic-lined units are presumably not susceptable to electrolytic failure, and their longer warranties reflect this.
An electric water heater that's fed clean, soft, non-corrosive water and kept reasonably clear of sediment can last over 25 years.
What, nobody mentioned Thermal Expansion!
All my heaters that are not on private well systems get a thermal expansion tank. The relief valve will dump at 150PSI, but my theory is that it stresses the tank and eventually will leak. Until the water departments started putting back flow valves on the water meters we didn't see nearly as many young tanks failing. OK, so someone will say, "They don't make them like they used to."
Out here in the boonies of KY, we have to install pressure regulators. The local water district has such long main lines that the pressure is pretty high. At last flush (around 1:00am) the pressure can peak near or over 150 psi. Split a whole bunch of tanks and popped T&P valves b/f they figured it out.
Dave
Peach,
What Dan said is correct. I taught plumbing at a vocational school for a few years and every year we would take 2 old water heaters apart. Never saw one leak at the boiler drain threads. All but one leaked from tank corrosion and annode rods were gone. One leaked from a leaking electric heating element. PS. If you are replacing your water heater go to the plumbing supply house and get one that will last. I am not one of the people who believes all HD and Lowes products are inferior but I know the water heaters are a substandard brand and you won't get 5-7 years out of them. DanT
Your theory is thoughtful, but I don't think it's what's happening. First, a round hole and a round pipe both stay round when they expand and contract, so they won't go eccentric. Second, the hole and valve material are both stressed under compression when the valve is tightened, so even if the hole expanded slightly more than the valve it would only relieve some of the compression, but not pull away from the valve, if the valve were tightened properly in the first place. I don't have my reference books with me at home, so I can't look up the difference in thermal expansion between steel and brass.
A plastic drain cock might eventually leak because the plastic could flow with temperature cycling and high temperature.
I read, understand and have actually seen it in one case, that some anti-thermosyphon devices and one way valves on the supply side of the water heater can cause pressure to build up to the point that the temperature and pressure, T&P, valve will trigger allowing small amounts of water to escape.
Theory is that cold water comes in and is heated. When heated it expands building up pressure. If it gets above the trip pressure the T&P can open slightly. If the water has a considerable mineral content the vent side of the valve can develop deposits that can keep the valve from closing all the way. A steady trickle of hot water can be leaking out. This can greatly increase costs in gas or electricity.
If the vent goes to a spot that is relatively enclosed, like a crawl space, it can lead to mold or even wood rot.
Sometimes just manually opening the valve a few times can clear the fouling and allow it to reseat properly. I saw a handyman remove the valve and scrape it and soak it in vinegar to remove deposits. I suspect a plumber would have just replaced it.
I understand that installing an expansion tank between the one way valve on the supply line and the water heater can eliminate the problem.
That my WAG anyway.
If there is a check valve or backflow prevenetion device on the house service (required by code in most jurisdictions for new construction or significant retrofits) expansion of water in the tank can be sufficient to pop the P&T valve. In other cases it may just lift enough to leak. This can also cause leaks at marginal pipe joints, particularly plastic drain valves. If you have a check valve or backflow prevenetion device you need an expansion tank similar to that used on home boilers, identical in many cases except for the pressure rating.
I think your right that this, adding an expansion tank, is likely to be the best long term solution to many of these issues.
id probably even guess that leaks are due to the installer not using plumbers putty or tef tape on the threads.
Also moisture can saturate the insulation and cause outside in rusting. Or the condensation of the hot water and cold air can cause moisture then corrosion on the steel lines.
Or the big boxes speced out cheaper tanks and unprotected tanks that are more prone to failure in order to keep the margins in a profitable area. Kinda like why the spec out plastic parts where metal parts are supposed to be to keep prices down.
I really wonder about the different specs. It may be an urban ledgend.
I went thru a North Carolina saw blade plant (jig, hack, circular, band) they had one assembly line one parts bin for raw materials. They made Vermont American, kmart, sears miller porter, master mechanic and several more products. only diff was the name. Same with an orange juice plant in Florida. one "assembly" line, 10 brands - foreman said the sugar content varied
Same is true of gasoline -- it all gets moved around the country in the same system of pipelines. Except for locally mixed additives, all the brands are the same stuff.
-- J.S.
I don't know if it is the same in the US, but in Canada all the oil companies have a program called "product exchange": they get their gasoline from the nearest refinery, and each month total up who got how much from who.
In Atlantic Canada, if you buy gasoline in NB or PEI, it's a 99% chance it comes from Irving; in NS, it's 99% Esso. No matter what station you buy it from.
"I went thru a North Carolina saw blade plant....... they had one assembly line one parts bin for raw materials. They made Vermont American, kmart, sears miller porter, master mechanic and several more products. only diff was the name. Same with an orange juice plant in Florida. one "assembly" line, 10 brands - foreman said the sugar content varied"
Wain,
Very true sometimes, but often when stuff goes through QC, the crap gets sold under one brand, and the really good stuff under another. Very common in the wine industry.
Just out of college my wife worked in the processed food industry (sales). Yes, she saw the same batches of stuff that was put in name brand containers ie, Kraft, Skippy, also put in private label. On the other hand, it DEFINITELY is not always the case. You never know till you do a side-by-side comparison.
Jon
Most canned goods are produced without labels. The labels are applied when they are shipped from the warehouse, allowing the same stuff to be sold under many different labels.
"I went thru a North Carolina saw blade plant....... they had one assembly line one parts bin for raw materials. They made Vermont American, kmart, sears miller porter, master mechanic and several more products. only diff was the name. Same with an orange juice plant in Florida. one "assembly" line, 10 brands - foreman said the sugar content varied"
Wain,
Very true sometimes, but often when stuff goes through QC, the crap gets sold under one brand, and the really good stuff under another. Very common in the wine industry.
Just out of college my wife worked in the processed food industry (sales). Yes, she saw the same batches of stuff that was put in name brand containers ie, Kraft, Skippy, also put in private label. On the other hand, it DEFINITELY is not always the case. You never know till you do a side-by-side comparison.
Jon
Jon:
Last year we went to a local plumbing dealer & and my wife picked out a faucet that she loved. A few days later I saw the same model number in a big box store for much less and wanted to buy it. But she wouldn’t go along with it because the plumber told her that Moen sold products with inferior parts to the big discount stores. (She was from the same “mold” as her father who believed the same). Since I was never in favor of replacing the faucet in the first place, I kept my mouth quiet … after 35 years of marriage, you “learn to pick your battles”.
In my “prior life” (prior to retiring), I worked for a US Fortune 5 company. Yes we did make other brands side by side with our internationally known products; many were “private labels” (i.e. a store’s brand) and sometimes even our competitors! However never did we manufacture or stock inferior parts for a SKU – it was just too risky to our company image, name, reputation, etc. (i.e. our company’s integrity! … moreover, having worked in manufacturing, it would have: 1) screwed up the production line for adjustments and, 2) been too damn expensive to manage the inventory!) We did however, offer product upgrades for features such as extended life, quietness, good looks, increased functionality, etc. But when we did, those products went out as a different SKU or model number, with these additional features promoted. So the point here, products from reputable companies (i.e. companies who have been in the business for years) having the same model/SKU number and in their original package from any local store vs. one from a discount center are the same. The original package needs to be a qualifier, cause I’ve been a victim where some cheap SOB (customer) switched another product into the package. - Rookie
To clarify your point, and with regards to Moen in particular, the "same" faucet sold at big box stores has a different part number from the one sold through plumbing wholesalers.
If you go to Moen's website, you can build faucets different ways, and what appears to be the same thing has different numbers. I know, I just went through 3 baths and a kitchen.....
"products from reputable companies (i.e. companies who have been in the business for years) having the same model/SKU number and in their original package from any local store vs. one from a discount center are the same. The original package needs to be a qualifier, cause I’ve been a victim where some cheap SOB (customer) switched another product into the package."
Rookie,
All I was getting at was...you never know unless you do a side by side comparison. You are correct that "private label" can be the same as name brand, but not always.
I understand where you are getting at with SKU's, and it makes sense. That doesn't mean that companies don't mfr. "inferior goods" for certain customers.
Jon
Edited 3/23/2004 10:37 am ET by WorkshopJon
Edited 3/23/2004 10:37 am ET by WorkshopJon
> Also moisture can saturate the insulation and cause outside in
> rusting. Or the condensation of the hot water and cold air can cause
> moisture then corrosion on the steel lines.
Well, there shouldn't be any moisture there unless something is leaking to begin with. The only place you'd get condensation is the cold water line -- the tank itself is warm enough to prevent it -- and any condensed water running down the cold water line would evaporate in short order on an operating WH.
The only real condensation problem with water heaters is in the heat exchanger of a gas unit. Except in the highest efficiency units there should be no condensation when the burner is running, but with standing pilot units the pilot can produce enough water to cause condensation, especially if the unit is turned to "pilot".
In any event, the couple of times I've seen a WH fail, the leak has been down near the bottom, where the greatest thermal cycling occurs and where sediment will add to problems.
"Well, there shouldn't be any moisture there unless something is leaking to begin with. The only place you'd get condensation is the cold water line -- the tank itself is warm enough to prevent it."
Dan
There is one scenario were you can have massive external condensation. If you run propane, and the tank runs out. Happened to me all the time before they ran gas up the road. You could hear the condensation dripping on the flame. Very bad in the summer.
Jon
I assume this happens because the tank goes cold?
"I assume this happens because the tank goes cold?"
Dan,
Yes, 50F well water chills the tank down pretty quick. Come Spring and Summer dew points are high enough to form heavy condensation on the exterior pretty quickly.
Jon
Did someone mention that the fuel matters big time?
Electric HWHs can last near forever if the anode rods are replaced.
Gas is a whole other matter. Most Gas HWHs rust from the outside at the bottom, due to acidic byproducts of combustion, and plenty of heat to speed the reaction.
Standard quality gas units often fail in 5-7 years. It's not unusual to have an electric unit run for 20 or more years.
My grandmother has an unusual stone-lined electric HWH that is 45 years old and going strong.
Its not the drain im glad you work at that highly respectable chain and not in the real industry. There supposed to leak keeps use in bussiness and people like you paying. Change the drain winde up with no hot water and call a plumber and not from hd. This post has got to be a joke just cant be real or can it. Steal rots thats why they use it.
Lets be careful out there. The combination of a failed T&P valve and thermostat can lead to serious consequences.
July 26, 2000
To: Joseph S. Lalli, Commissioner
Thomas L. Rogers, Chief of Inspections
From: Mark F. Mooney, Assistant Chief of Inspections
RE: Avon High School Hot Water Heater Explosion – Final Report
On Friday, May 12, 2000, the Department responded to report of a pressure vessel explosion, at the Avon High School. At the request of the State Fire Marshal’s office through Sergent Viola, I arrived at the site to investigate the incident.
It was determined that a five (5) gallon electric hot water heater located in a storage room immediately adjacent to the high school cafeteria catastrophically failed causing severe damage to the surrounding area.
The blast occurred at 6:05 p.m. Thursday, May 11, 2000. Two custodians, Sharon Brennon, and John Morrata, were working in the cafeteria minutes prior to the failure. They indicated that they were working immediately beside the wall that collapsed just before they went for a coffee break. Just as they took their break, Ms. Brennon indicated that they heard a “big boom” and immediately ran for the door fearing a secondary gas explosion. Ms. Brennon and Mr. Morrata did not previously respond to any problems with hot water that day, but they worked the afternoon shift that did not require any demand for hot water on that system.
Earlier in the day prior to the failure, the day shift custodian Aubrey Williams indicated that they he had responded to several calls for cold water in the cafeteria kitchen. He indicated that he had to reset the tripped hot water heater circuit breaker 2-3 times between 10:00 a.m. and 11:30 a.m. Because his efforts did not correct the cold water problem, he thought there may have been some other breakers tripped in an area that he could not access due to asbestos removal.
The vessel that failed was a 1981 Hatco Electric Hot Water Heater, model # HCI-2464, serial #27492-TL110. The vessel was UL listed with a 150 PSI rated working pressure. The heater was rated for 1 amp, 3 phase with a total kilowatt rating of 17.2.
The hot water heater failed at a weakened area near the welded longitudinal lap joint. It appears that this thinned area may have been leaking slightly during the day resulting in abnormal conditions in the heater. These abnormal conditions may have contributed to the temperature control and breaker problems indicated earlier in the day. As the thin area failed the longitudinal seam also failed along the heat effected zone of the weld.
Failure of the pressure-temperature safety valve along with the corroded and weakened condition of the vessel resulted in the ultimate failure of the vessel. Other schools in the Avon school system were visited to ensure there were not similar vessels in operation at those facilities.It is recommended that a release be issued to cover the recommended preventative programs schools, homes and businesses should follow to ensure a similar occurance does not happen with more tragic results.
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