tzzzz216

I replaced a thermostat upper in a water heater 4 days ago , only after testing the upper and lower elements , the water was even hotter afterwards , the customer called me today and said the water isn't as hot as it was , keep in mind the last 3 days the water was hot, it just him and his wife and the heater was installed when the house was built 3 years ago, Can i be getting false reading on the elements ??

Ron The Plumber

You did put the wires back on the same terminals as they come off at right?

Water heater getting to hot, is an indication of bad stat/s, could you have installed defective stat/s?

If they are saying it's not as hot now, did the upper stat trip, if so it would soon cool down and never heat up again, have they indicated water is no longer hot but cold constant?

The questions I ask cause I don't know the time line from when it was extra hot to when they called and said it's not as hot now.

I'd check the breaker on the stat, did you replace both upper and lower stat?

I will test the elements with an ohm meter, if there good, meter will have a reading, if not there there will be no reading.

How do you test your elements?

mdshunk

Can you describe the exact procedure you used to test the elements?

tzzzz216

I'll answers Ron questions first.

I put the wires back on the same terminals and also used same brand stat whirlpool.

It could be a bad stat, but it shut off when i turned it down to 90 and back up to 120 degrees came bach on , I know thats not saying much.

The old upper stat never tripped the first time, but what i did i turned it down to 90 degrees and it wouldn't shut off then i turned it up to 150 degrees and it shut off, that was telling me it was satisfied temp and shut off. They said the water is getting hot still but the temp drops after she takes a bath and he shaves, I was just here thinking i wonder how long she has been taking a bath , and not a shower , The reason i say this is because i also replaced the flapper in the masterbath and saw this large Jacuzzi in there, that it'll use up hot water fast filling that up.

I just replaced the upper stat .

Time frame : Same day ,when i felt the temp at the faucet it was about 105 -115 with the old stat was set on 125 after i put the new stat in waited few felt the temp again it felt more like 125 -130 temp now 3 days later their saying it feels like it did before the new stat, hot but then the temp drops down .

Ron and mdshunk , testing elements , I'm using a test probe disconnect both wires, probe on one terminal and the clip on the other, this hasn't really failed me yet

Thanks guys for the help your always right there to give information and help !!

Ron The Plumber

How large is the water heater?

mdshunk

Can the dip tube be broken off/rotted off? "In" and "Out" pipework reversed?

Is there any unusual hot water use lately? Quick story... I got a service call for an ice machine at a country club that was not making enough ice... it was not "keeping up". I went there numerous times, tweaked several things, but found no "smoking gun". I went there early one morning for like the zillionth service call, and found the caddies loading big hoppers full of ice and loading them in some golf carts. I asked them where they take them. They said, Oh, we started doing this lately during hot weather and we keep bins of cold drinks on ice out on the course. Mystery solved.... that's were the ice was going. The kitchen staff showed up hours later and thought the ice machine wasn't working. They actually needed a second ice machine for the caddies.

Ron The Plumber

I'd go and run a tub of straight hot water and just see how long it takes before the cooling down period.

tzzzz216

The heater is 50 gallons, and probably a good 25-30 feet from the bathroom .

tzzzz216

It very well could be but , its piped in correct , except for the relief line some piped it going up and over the top of the water heater , I guess when they rough in for the heater they would get one with the relief on top , this one is mounted on the side , I advised the HO of the problem and noted it on my invoice for the records , he had no concern over it .

Double-A

A 50 gallon heater will only deliver 60% of its rated capacity before its not 'hot' water anymore. So you're talking 30 gallons of water.

If your start temp was 130 degrees, the ending temp of the water, after 30 gallons of draw down should be about 30 degrees less than what you started with, or about 100 degrees. After that, the temp will fall off sharply.

If you have a 5.5 feet long tub 3 feet wide, and 15 inches (1.25 feet) of depth (to the overflow), it will hold about 154 gallons. There are 7.5 gallons to the cubic foot.

5.5x3x1.25=20.63 cubic feet
20.63x7.5=154.69 gallons

Now, depending on if they draw from surface water or from well water, the incoming cold water temp could be from 60 degrees for a shallow well, to a low of about 35-40 degrees.

In our area, a cold water temp of 40 degrees in winter is not uncommon.

Now, most folks shower at about 106 degrees, so to raise 154.69 gallons of 40 degree water to 106 you would need 128.39 gallons of 130 degree water.

Incoming cold water of 60 degrees will use 102 gallons of hot to give you 154.69 gallons of 106 degree water

% of hot water = (mixed temp {your target temp} - cold temp.) divided by (hot temp - cold temp).

Now, this gets more complicated than this... you start with 130 degree water, but as you fill the tub, the temperature goes down, requiring more and more hot water, until you hit 105 degree, at which point you have to stop filling the tub and let the water heater recycle or you will start cooling of your bath water.

Is this sucking yet?

I guess what I'm getting at here, is that you may not have a problem with the water heater. You may have an unreasonable expectation of that water heater. It just can't fill a large spa tub with hot water.

Set both stats (upper and lower) to approx 130 degrees and let them both come on and turn off (satisfy). You should water at the tub from between 120 degrees and 140 degrees. Now, start measure the temp and the amount of water you can draw before you drop 30 degrees. You should get about 30 gallons. Go turn the t/stats back down to 120 now. Don't leave them turned up.

If you are getting this, then the heater is working properly. If not, check your lower t/stat and element as they are the most common source of 'lack of hot water'.

Otherwise, install a tempering valve and set it to 120 degrees, and crank that water heater up as high as it will go, but do install that tempering valve. You don't want anyone getting scalded.

__________________
"My clients’ wishes are the center of my attention." -- David Guido, a contractor in Woodstock, N.Y.
New York Times, July 20, 2006

gitnerdun

I think I would check the tub manufacturer's specs for capacity, there aren't very many perfectly square tubs out there and they don't fill to the rim. I think the heater is undersized, but not by much. If there are no kids, advise the HO how to increase the temp, therefore you aren't responsible, Then they will mix more cold water at the tub valve. The next size up is a considerable increase in price. Might be a good place for a "tankless". Just my 2 cents. Bob