Water just warm, not hot

**higgledy** · 10-29-2012, 11:39 AM

I need some advice with my water heater, it is a 5 year old Sears Power Miser 12, which I think are made by State. It only heats the water to warm, at best. I checked both elements with an ohm meter and visually. Both measured about 12 and 15 ohms across their terminals and both looked good, too.

I tested the thermostats per the instructions on this page, http://www.water-heater-repair-guide...hermostat.html

The one thing that did not checkout was I got 0 volts across the lower element terminal thats with the upper thermostat set to the coldest setting, and the lower thermostat set to its hottest setting. That should have kicked power to the lower element. Correct?

I then replaced the upper thermostat, but same thing. I want to replace the lower thermostat but I can't find an exact match. Does the replacement thermostat need to match the top exactly? Or can I use a different brand, but same volt/watt/current rating.

Sorry for the long winded post. Thanks for any replies.

**Terry** · 10-29-2012, 09:33 PM

The upper thermostat puts power to the upper element first. If the upper is burned out, there will be no heat.

The lower only comes on, only if the upper has been satisfied. So you can wind up with less hot water if only the upper is working.

You would normally set both thermostats for the same temperature.

hj · 10-30-2012, 07:04 AM

It is easy enough to tell if the lower thermostat is the problem. Check for power between its two terminals. If it is ZERO the thermostat should be okay, if it is 220/240 then it is open, and there may be a problem with it depending on the water temperature. There are only four test that have to be made;
1. Does the upper thermostat have power, and if not, why not
2. Is there power to the upper element and if so is it being used
3. Is there power to the lower element and if so is it being used
4. Is the lower thermostat functioning properly

The lowest setting on the upper thermostat does not necessarily active the lower element. it depends on the water temperature. I NEVER test elements with an ohmeter.

**higgledy** · 10-30-2012, 01:46 PM

Originally Posted by hj

It is easy enough to tell if the lower thermostat is the problem. Check for power between its two terminals. If it is ZERO the thermostat should be okay, if it is 220/240 then it is open, and there may be a problem with it depending on the water temperature. There are only four test that have to be made;
1. Does the upper thermostat have power, and if not, why not
2. Is there power to the upper element and if so is it being used
3. Is there power to the lower element and if so is it being used
4. Is the lower thermostat functioning properly

The lowest setting on the upper thermostat does not necessarily active the lower element. it depends on the water temperature. I NEVER test elements with an ohmeter.

Thanks. This afternoon I replaced the upper element. Now, both elements are new.

How long would you expect to have hot water after filling the tank? It's been powered for two hours and all I have is tepid water at the tap. Yes, I did fill the tank and run a hot tap for several minutes before applying power. Thanks.

If it does not get hot tonight, I'm calling a professional tomorrow.

**higgledy** · 10-30-2012, 01:54 PM

Originally Posted by hj

It is easy enough to tell if the lower thermostat is the problem. Check for power between its two terminals. If it is ZERO the thermostat should be okay, if it is 220/240 then it is open, and there may be a problem with it depending on the water temperature. I NEVER test elements with an ohmeter.

Which two terminals? i am measuring zero vac across the lower element. This is while the upper element has 240vac. From what you guys say, this is correct.

Is it ok if I replaced the upper element with high watt density rated at 3800W? The original was a 3800W low watt density (folded) element. None of my local stores had a LWD element at 3800 watts...not even one at 3500 watts. Thanks

**higgledy** · 11-01-2012, 06:57 PM

I hired a licensed plumber to fix my water heater. He replaced both thermostats and both elements and I still am only getting warm water. Does anyone have any ideas what else might cause just warm water? It's not that I get hot water and then it goes cold. It's just warm all the time. Thanks.

**Terry** · 11-01-2012, 07:07 PM

Is this in a home, or an apartment building?

**jadnashua** · 11-02-2012, 02:51 PM

Are you getting the same on all taps in the house? Have you tried seeing how hot the water is from the WH drain line? Do you have a recirculation system? A recirculation system would have a check valve, and that may have failed, allowing cold, or less hot water get to your valves. Water will take the path of least resistance.

A faulty shower or sink valve can allow the hot to mix with the cold, giving you tepid water in many places. But, first, you need to test the water temp out of the tank. If that's hot, then you have a problem elsewhere. If not, it's either the tank or its input power. A CB that is failing could limit the power to the tank. A bad wiring connection could limit the power to the tank. This is why an ammeter is useful...it measures how much current the line is carrying, and not the potential.

**LLigetfa** · 11-02-2012, 03:15 PM

Maybe the pipe goes under a slab and you have a leak. The water heater may not be able to keep up with the demand.

**higgledy** · 11-03-2012, 06:05 AM

This is in a home. There is no circulation pump involved. There are no pipes other than drains running under the slab.

The plumber, whom I've hired before, he's always done good, neat work for me. He knows what he is doing. He says he cannot find the problem. The tank is clean, dip tube fine. Internal wiring checks out fine. Voltage at the WH is correct, running 10AWG on 30Amp circuit---circuit breaker is fine, too. It's just the bottom element never gets energized. i.e. the top element is never satisfied.

Water drawn from the WH drain is cold--like straight from the tap cold. Water drawn from the TP valve is warm.

My plumber called my wife last night and told us he is baffled by our WH. He says that in his 25 years, it is the first WH he has not been able to fix or figure out why it is not working.

BTW, my water heater is seven years old, not five years old as I originally stated. I counted wrong. :\

Any ideas?

**higgledy** · 11-03-2012, 06:08 AM

Originally Posted by jadnashua

Are you getting the same on all taps in the house? Have you tried seeing how hot the water is from the WH drain line? Do you have a recirculation system? A recirculation system would have a check valve, and that may have failed, allowing cold, or less hot water get to your valves. Water will take the path of least resistance.

A faulty shower or sink valve can allow the hot to mix with the cold, giving you tepid water in many places. But, first, you need to test the water temp out of the tank. If that's hot, then you have a problem elsewhere. If not, it's either the tank or its input power. A CB that is failing could limit the power to the tank. A bad wiring connection could limit the power to the tank. This is why an ammeter is useful...it measures how much current the line is carrying, and not the potential.

Water temp at the WH is cold from the WH drain and tepid-warm at the TPV, same as I am getting at the tap.

It is not the CB because the top element is working and the plumber measure 18+amp draw while in operation. I am thinking an 18amp load would be enough to energize the bottom element or at least show a faulty CB.

**LLigetfa** · 11-03-2012, 06:26 AM

Originally Posted by higgledy

This is in a home. There is no circulation pump involved. There are no pipes other than drains running under the slab.

It still sounds like hot water is being consumed faster than the heater can reheat it. Even with just the top element heating, you should get hot water, just less of it. Are you 100% certain that there isn't a continuous draw on the hot water? Check the water meter when there is no water usage.

**higgledy** · 11-03-2012, 06:34 AM

But even if there was a water draw wouldn't the bottom element kick-on at some point? Plus, if it drawing enough water that the water heater could not keep up, wouldn't I hear water running in the house? Like the noise you hear when the garden hose is running. To play it safe, I am at work now, but I'll check the water meter when I get home tonight and get back to you.

**LLigetfa** · 11-03-2012, 07:36 AM

I have had gas water heaters for nearly two decades now so have not needed to stay abreast of the technology used on electric water heaters. That said, I doubt the technology has changed.

An electric HWT with a bad bottom element basically gives you the same temperature water, just less of it. The water stratifies... hot rising, cold settling on the bottom.

An electric HWT with a broken dip tube can cause the stratified hot water at the top to blend with the incoming cold affecting the temperature.

In some code jurisdictions, a tempering valve is required after the HWT, the purpose of which is to blend in some cold water if the temperature is above a preset. One would assume a plumber worth his salt would recognize and know how to diagnose a bad tempering valve, but I'll throw this out here JIC it was overlooked.

**higgledy** · 11-03-2012, 10:11 AM

The plumber pulled the dip tube, it is intact. The bottom element is not bad, it never gets power --the top element never gets satisfied. There is no tempering valve in my system, it is not code in my area.

You are lucky to have a gas water heater. If I had natural gas in my neighborhood, I'd dump electric in a second.

Here is a link to a water heater problem nearly exactly like mine. He's final solution was to replace the water heater.

http://www.justanswer.com/hvac/1wuru...es-not-on.html