Cold water inlet temperature

I am wondering if prolonged cold spells substantially reduce the temperature of the water entering a house from the city water service . . .

. . . and if that's true, does that temperature drop translate into increased stress on water heaters? My neighbor's just failed and last week we had a water main rupture, too. I can't help but wonder if these are temperature-related failures.

How would you go about measuring the inlet temperature of water? My thought is to let the cold water run for about 3 minutes to "cold soak" the pipes (copper, in my case, uninsulated, too) and then measure the temperature at the tap.

Letting it run for 3 minutes produced 41.5F on two different digital thermometers so I guess the answer to my question is that yes, the inlet temperature varies based on the outside temps and quite a bit more than I would have imagined. FWIW, it's about 29F outside and has been fairly cold out for a few weeks.

I'd like to be able to monitor and log the inlet temperature, but it would be hard to automate a 3 minute "cold soak" measurement like the one I just took. I have a HomeVision home automation controller that would allow me to attach a TI digital sensor to the inlet pipe where it enters the house in the basement. I can log those temps to the PC but it would be a) "contaminated" by the room heat and b) would vary substantially based on how much water is or isn't flowing past the external sensor. I suppose I can discard all but the lowest reading and perhaps put some insulation over the sensor and around the pipe to reduce the effects of room heat on the sensor.

Thanks for your input in advance . . .

Reply to
Robert Green
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I'm curious, lets say you prove that it is true. Short of moving to a warmer climate, what do you intend to do about it? Seems like a lot of work without much in the way of ROI.

In my case, the water in the pipes in the basement are colder than the water entering the house. But that's because I keep my basement at around 35 degrees in the winter. My water heater failed one summer, but it was about 25 years old and likely due to fail anyway.

Reply to
Mark Storkamp

Yes. Our tap water varies from lukewarm in the summer to ice cold in the winter, in central Virginia.

Reply to
TimR

In coming water is definitely colder here in suburban NJ in winter too. That's why it's good to have automatic temp adjusting on washing machines. The older ones just gave you cold, half and half for warm, or hot. Newer/better ones mix it to the correct temp. In winter mine adds some amount of hot water, even if you have it set to cold.

Reply to
trader4

On Monday, February 10, 2014 10:40:30 AM UTC-6, Robert Green wrote:

ure of the water entering a house from the city water service . . . . . . a nd if that's true, does that temperature drop translate into increased stre ss on water heaters? My neighbor's just failed and last week we had a water main rupture, too. I can't help but wonder if these are temperature-relate d failures. How would you go about measuring the inlet temperature of water ? My thought is to let the cold water run for about 3 minutes to "cold soak " the pipes (copper, in my case, uninsulated, too) and then measure the tem perature at the tap. Letting it run for 3 minutes produced 41.5F on two dif ferent digital thermometers so I guess the answer to my question is that ye s, the inlet temperature varies based on the outside temps and quite a bit more than I would have imagined. FWIW, it's about 29F outside and has been fairly cold out for a few weeks. I'd like to be able to monitor and log the inlet temperature, but it would be hard to automate a 3 minute "cold soak" measurement like the one I just took. I have a HomeVision home automation controller that would allow me to attach a TI digital sensor to the inlet p ipe where it enters the house in the basement. I can log those temps to the PC but it would be a) "contaminated" by the room heat and b) would vary su bstantially based on how much water is or isn't flowing past the external s ensor. I suppose I can discard all but the lowest reading and perhaps put s ome insulation over the sensor and around the pipe to reduce the effects of room heat on the sensor. Thanks for your input in advance . . . -- Bobby G .

Here in suburban Chicagoland, there is almost always a rash of municipal wa ter main breaks after a good cold snap, due to the water mains shrinking du e to the scold temperatures that get down to the level of the installed pip es. Unless there are some strain reliefs periodically, the shrinkage cause s stresses and the weakest one breaks. Stress relief usually takes the for m of an "S" bend periodically.

Reply to
hrhofmann

If the water heater has to operate longer to bring the incoming water up to temperature translates into " increased stress", then so be it. But that's how it is supposed to work. MLD

Reply to
MLD

Do you mean to say you can't think of *any* inexpensive or cost-free way to reduce potential thermal stress on a water heater when the inlet temperature goes very low? I can think of several off-hand.

That's pretty unusual for most homeowners I know.

Reply to
Robert Green

Our house - 60 years ago in Chicago - had a "tempering" tank. An uninsulated, unheated tank of about the same size next to the HW tank. That's the only way to reduce HW tank inlet temp I can think of - that makes sense and is cost effective, Don't think it was used to reduce "stress." Probably to increase capacity for a smaller water heater. Or to sell the "tempering" tank. Only reason to have one nowadays is perhaps to "temper" water for the on-demand type heaters.

Reply to
Vic Smith

winter, in central Virginia.

I used to notice things like this when I had a darkroom but it's been a long time. I was surprised to read it at 41.5F. Does anyone know if well-water is subject to the same temperature swings as municipal water?

Reply to
Robert Green

In the winter I trim the washing machine "cold" valve to about half flow. Takes longer to fill the tub but Ye Olde Kenmore has simple hot/warm/cold settings and no capacity for automatic temperature adjustment. Since it's set and forget operation, the longer fill times don't bother me much. I think the next time the shower/diverter valve needs replacing, I will choose a thermostatic unit. There's a chance of doing real damage if the shower temperature drifts too much.

Reply to
Robert Green

If NASA had a little foresight about the problems of cold weather, they might not have dropped the Challenger into the ocean. If the USN had realized what happens to ballast blow valves (as they were designed before

1963) at depth (they froze solid) the Thresher might not have sunk.

What I am concerned about is limiting the delta between the incoming very cold water and the much warmer tank interior. There are several ways to go about that.

I've already taken one step, which is to reduce the incoming pressure to the whole house. That slows down the amount of water that can enter the water heater and reduces the potential thermal stress.

I'm also going to turn the water heater's thermostat down just to lower the over all temperature differential. The cooler the WH output, the lower the delta between incoming and outgoing water.

A third action is to trim the hot water feed valve to the washing machine so that it doesn't draw anywhere near the GPM of a wide open valve. It will take longer to fill (will be measuring that as we do laundry) but it's not a very big thing to wait an hour instead of 30 minutes for the laundry to be done. It's not like I am outside in the bitter cold beating the clothes on river rocks. (-:

A fourth action will be to avoid the HOT only wash cycle during bitter cold months (we typically wash our LBL dog's blanket in hot water), thus further slowing down the amount of cold water that's introduced into the tank quickly and lowering the thermal "shock" to the heater.

If I wanted to spend money, I might look into a pre or post water heater expansion tank or put aluminum fins on the pipe leading from the master intake to the water heater. That's at least 25' feet of copper pipe that could transfer some room heat into the incoming water, but I think that's way overkill.

I think reducing the pressure and the temperature while taking care not to draw enormous amounts of hot water will substantially reduce the thermal differential and the risk of catastrophic failure from thermal stress. It will be just my luck that it fails as a result of crud getting into the lines from the recent water main break, but at least I will have tried. (-:

Reply to
Robert Green

By now you've probably read about the things I intend to experiment with to nurse the heater along through the supercold weather. So far, so good with the pressure drop and I am about to do a load of laundry to measure the fill rate.

The shower massager still pulses (turns out to be an excellent informal pressure gauge by accident!), the toilet's taking a little longer to fill and the bathroom sink is unusually low-flow and probably indicates something's amiss somewhere other than the screen. That fixed the low flow in the kitchen but not in the bathroom. So reducing pressure as a test actually had a diagnostic side effect. It really slowed down the flow from screens clogged with spooge.

Probably not, but you're in a cold enough climate that you never know, IIRC.

You said "next to" the heater - was it in line before the heater or after? Before it might have indeed been a pretempering device.

Yeah, what he just said. (-:

Oh, 25 to 50 extra gallons of potable water on premises can't be a bad idea, overall. In DC, we worry about dirty bombs and other "cakes baked" by those with an anti-government agenda, foreign and domestic.

While I don't think thermal stress is a great contributor to the *overall* wearing out of a water heater, what I've read so far convinces me that a long bout of very unusually cold weather will kill off the weaker water heaters in the herd. And by age alone, mine's a downer heater.

Speaking of euthanizing water heaters, how about that giraffe? I've already read two different versions. Killed by shotgun, killed by boltgun. I love the uncertainty of breaking news. (-:

Putting down "excess stock" makes me worry that one day when it's time to retire the boss will say: "Vic, Bobby - your outtake interviews are in room one" and Anton Chigur from "No Country For Old Men" will be waiting in there with his compressed air tank. PFFFFT!

(Wouldn't that thing get all matted up with dried brain goo?)

Reply to
Robert Green

No, I'll go look. Okay, you basically throttled down the input, and turned down the water heat. Seems a drastic step to take to reduce the possibility of thermal shock. But tinker if you want to. Cant hurt unless you screw up the valve. I did the throttling bit once with an old gas furnace that was throwing too much heat up the stack, but that was a different case. I think you're making too much of it.

Before. I removed it when I put a new WH in. It was old, and just another failure point. BTW, the water temp at the Lake Michigan intake crib whence my water originates, is currently 32 F. Don't know what the cold water Temp in the house is. Except it's pretty cold.

You're probably better off with a tempering tank to serve that "need." I did a quick look and didn't see anybody selling them. You need a tank able to withstand municipal water pressure. Costly.

I haven't followed it, but wonder why they don't use birth control to avoid "excess stock." Saw that movie, but don't remember an air tank. Sorry (-:

Reply to
Vic Smith

They definitely do.

Winnipeg gets it's water from Shoal Lake, which is a lake in the Whiteshell Provincial Park about 60 miles from Winnipeg.

If you have a single lever shower faucet, just take note of what the faucet handle position is in summer and in winter. The hot water in your water heater will be the same temperature (or close to) year round, so that the difference in handle positions is entirely due to the warmer cold water in summer and colder cold water in winter.

Water main breaks aren't caused by the pipe shortening due to thermal contraction in the cold. Normally, in winter, the ground freezes to a certain depth which we call the "frost line". Water supply pipes and sewer lines will be buried well below that frost line so that the water in the pipes doesn't freeze. But, what happens is that as moisture in the ground freezes and expands AT the depth of the frost line, ice "lenses" form. They are called ice lenses because of their shape; being thickest in the middle and thinnest at the edges. These ice lenses are very localized, typically being no more than about 100 feet in diameter. It's the downward pressure exerted by the water as it freezes to the bottom of the ice lens and expands that causes water pipes to break underground. The force of water expanding as it freezes is pushing down on the pipe one place, and as little as 30 or 40 feet away, you don't have that pressure, and so the pipe bends until it breaks.

Reply to
nestork

Hi, Here in Calgary, most house has water pressure gauge set at 60 psi when water is running. Winter/summer, no difference. Our pipes are minimum

6 feet below ground. Is some one paranoia of something? Water heater is designed to work normal under normal conditions. I wouldn't worry and fiddle with it. If some one wants to experiment to prove some thing, it'll take at least for the life of water tank with every thing observed/measured documented. Also water main butrssting in cold weather is due to rather from the ground heaving than freezing water causing water lens.
Reply to
Tony Hwang

"Robert Green" wrote in message news:ldb0m8$5ah$ snipped-for-privacy@speranza.aioe.org

It depends upon where you live and the source of the city water.

If you live somewhere that has wide swings of temperature from season to season the water temperature will also vary and the anount of variation would change with ground water depth. If the source is surface water as opposed to ground water it will vary even more. FWIW, the water in Honolulu (ground water) varies about 2 degrees between winter and summer.

I would think that temperature variation also depends upon how the water is stored, transmitted and the overall rate of use. For example, if you live somewhere that uses ground water but provides a head to it via elevated storage tanks, the ground water temperature is going to change in the storage tank, colder in the winter, warmer in the summer; however; if the water in the tank is being used and replenished rapidly, that variation would be minimized.

I get my water (central Florida) from my well which is about 110'. At the moment, I set my single handle shower mixer at about 10:30; come August, it will be at 1:30 so there is considerable temperature variation in the source, no idea how much in degrees.

Reply to
dadiOH

"Robert Green" wrote in message news:ldbkfi$vfi$ snipped-for-privacy@speranza.aioe.org

That would limit the rate but would have no effect upon ther amount. ___________________

It also means that the hot water temperature will be lower which means you'll need a greater amount of it to get the same temperature fom a mixing valve faucet. ___________________

I think you are busy making mountains out of mole hills :)

Reply to
dadiOH

I'm sure. The water coming from the cold water faucet is colder in the winter than in the summer. And I've noticed it's even colder this winter.

People often use "stress" or "strain" to talk about machines. I think it rarely applies. The water heater elements are on more if the input water is colder. If the elements are going to wear out, they wear out that much sooner.

Sounds about right.

You can put the thermomenter in a short glass of water and watch the temperature as the running water replaces the water in the glass and see how long it takes until the temp stops dropping. (I know, ony part of the overflow is old water, but you can figure it out.)

Reply to
micky

Drastic? DRASTIC????? Adding an expansion or tempering tank or putting fins on the portion of the pipe from the main shut off/building inlet to the water heater would be drastic. These are "fixes" that took nothing more than the twist of a valve or a dial. (-: Not even a full twist, either.

Another county heard from. Ironic since I am not advising anyone to do what I am doing.

I'd agree with your assessment if you were living next door and I could grab you during the middle of a serious snowstorm and get you to help me replace the tank while saying "I told you so." But I doubt that any of the posters who have claimed I am worrying too much is going to be standing beside me helping me repair things in the bitter cold if they guessed incorrectly.

I got to quiz the plumber as he replaced the unit in my neighbor's home today and he said they had almost three times the number of emergency calls about water heaters as they normally do. Something about this incredibly long, incredibly cold spell is resulting in aging water heaters having "aneurysms" and failing at an accelerated rate. I've noticed that trend and want to see if there's any way to keep myself from being that plumber's next service call.

That's interesting because the plumber installed just such device today before the water heater - it looked like a small propane tank. He said the expansion tank was now required by code in the county. Might have been the same for the tank you removed. Did it pass inspection after the change or has it been inspected? IIRC, Chicago, like NYC, has some of the strictest building and fire codes in the nation. I seem to recall that both cities still require armored cable but they may have finally decided to embrace Romex.

Jeez, that ISs pretty damn cold! All the articles I've been reading about burst pipes and water heater failures (sample below)

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seem to agree that there are things you can do to extend the life of your heater and turning down the thermostat is one of them.

Agreed. Right now there's 25G of potable water stored in Nalgene tanks in the old darkroom (that was converted to an animal hospice). A expansion tank would insure that water's always fresh but I'd have to be able to pump it out if the water's cut. But that would be a "drastic" solution. I want to take some simple precautions to avoid experiencing my neighbor's fate.

Today, the plumber, when briefing my neighbors about their new heater, warned them that the higher the tank temperature is set, the shorter the tank's overall lifespan. The hotter the water, the faster corrosion takes place. Also, the greater the temperature delta, the more the unit cycles within a given time period. I alread discovered those facts reading about heater failures, but it was good to know the plumber agreed.

So I rolled back the temperature AND the pressure until the normal weather returns. Seems like a very simple, very un-drastic precaution to take when an old, old water heater is exposed to inlet water colder than it's ever seen in its entire service life. I can live with slightly cooler hot water for a few days or weeks more. As long as it's warm enough to shower comfortably (and it is) there's no big whoop. Since I've got a Floodstop electrical master shut off valve AND a manual one, I am not afraid of buggering the valve by adjusting it to compensate for the extreme cold.

By now you've *had* to have heard of the Copenhagen Zoo's serious public relations nightmare. They're in more trouble than Chris Christie. (-:

So are a lot of people. People are also wondering why the zoo didn't take up the several valid offers to accept the "surplus" giraffe instead of chopping it up in front of zoo visitors. I suspect the zoo's director will soon be retiring or looking for a new job. It's a classic case of scientists getting so wrapped around the axle that they are unaware of how their actions will look to non-scientists - in this case zoo patrons who are far less concerned with inbreeding than they are with the concept of zoos killing healthy animals that could *easily* have found a home elsewhere.

Holy Moly, Vic. He carried that tank (connected to a bolt gun) everywhere. It WAS the freakin' star of the movie! The killer (Javier Bardeem) went around using it to pop locks out of doors and brains out of people's heads. The ghosts of Siskel and Ebert, former Chicagoans and renowned movie critics are weeping in heaven for you. (-:

Reply to
Robert Green

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