Third new water heater - not enough hot water

[Diane18]

After over ten years, my Rheem 40 gallon electric water heater had some slight leaking. Water didn't stink and I had plenty of hot water. No complaints, but couldn't chance a failure.

I had the Rheem replaced with a Ruud 40 gallon electric water heater. After two months, I had rotten egg smell and turned the temp up to 145 degrees. Smell went away, but soon I didn't have enough hot water. Tests showed only one element working, so they replaced the tank rather than the element. New Ruud didn't have enough hot water to fill a tub. They replaced the thermostat. Still not enough hot water. Couldn't even fill a quarter of a 37 gallon tub. After testing, they decided the thermostats were being burned out by 5500 watt elements, so they put in 4500 watt elements and new thermostats. Still not enough hot water. I decided to go with a different company and brand. Installed an AOSmith 50 gallon electric. Temp set at 120 degrees. Not enough hot water for a lukewarm half bath or quick shower. I'll turn the temp up to 140 degrees, but don't understand what is going on here.

30 amp, double pole, 10 gauge wiring. Breaker has never tripped.

Thanks for any help.

Diane

 

[Reach4]

Still not enough hot water.

Does the water come out plenty hot in the first few minutes, but then turns cool after several minutes? I think that is what you are saying, but just checking.

 

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[hj]

Whoever worked on the first two heaters must not have known what they were doing, because their "diagnosis" and cures were incorrect.

 

[Jadnashua]

Is the house on a slab, or is there a basement? If on a slab, and the water line from the WH runs underneath the slab, there could be a leak and it has nothing to do with the WH.

 

[Diane18]

Does the water come out plenty hot in the first few minutes, but then turns cool after several minutes? I think that is what you are saying, but just checking.

Water comes out cool, turns hot within 30 seconds, but wasn't getting super hot. Plumber told me yesterday to turn up the temp to 140 on both thermostats, so I did. I now can fill the tub 8 inches, but can keep my hand in the water the entire time, so it is hot, but not scalding. The second water heater would seem hot one night and then the next no hot. I went from full tub, to 3/4 tub to 1/4 tub. Not using after wash or dishwasher. This third hot water heater has a higher capacity. The 40 gallon could only fill tub with 5 inches of water and then cold.

The house is a walk out and this is on the lower level with footings. Water lines run along the footings and then into the house, into pressure tank from well. I'm not thinking leak because the pressure tank isn't kicking on.

Thanks for any help/answers/thoughts.

 

[Reach4]

So the problem is that the water does not come out hot enough.

Look around the WH for any devices that might be mixing in cold water. There is a device called a tempering valve. People put these in on purpose, and some people will get upset if you don't have one. Most of those have an adjustment that allows you to raise the mix temperature.

 

[Diane18]

Definitely not hot enough or long enough. I'll check on the tempering valve, though don't know why old water heater worked without issue and three new ones don't. I know there are no hot water control valves in the faucets or tubs. I did have it adjusted on one shower, so it can't get hot.

 

[Reach4]

Definitely not hot enough or long enough. I'll check on the tempering valve, though don't know why old water heater worked without issue and three new ones don't.

It is possible that the calibration marks on the thermostat are not accurate. If you hold the WH output pipe when you have just started filling the tub, is it too hot to hold? At 140 it should feel very hot.

Even better would be to get an inexpensive IR thermometer. That would let you put a number to it rather than feel.

 

[Diane18]

Well, maybe it's working. Had plenty of hot water last night for bath. Plenty this morning for hot shower. Just did a hot water wash and ran more hot water in the tub. Yes, WH output pipe is very hot. Plumber will be out again to put in some air? tank between the softener and hot water heater, so I'll see if he has an IR thermometer. Interesting is that when we disconnected the Ruud, after I had shut off water to it and drained the tank, air came out when the plumber loosened the fitting. Also, the cold water inlet pipe was very, very hot on the Ruud installation. Not just radiant heat. This time it didn't get hot on installation. And, I had intermittent hot water before with the Ruuds. Maybe 120 first day on water heater after 8 hours wasn't long enough for water to get hot? I'll cross my fingers and hope I consistent hot water.

Thanks for your help.

 

[Reach4]

Plumber will be out again to put in some air? tank between the softener and hot water heater,

That would be the thermal expansion tank. I infer you have city water.

so I'll see if he has an IR thermometer.

They are often under $20, if you want to order one for future use.

 

[Jadnashua]

If you have a tire pressure gauge and a bicycle pump, it only takes a few moments to check and potentially fill an ET.

First, unscrew the cap. IF water comes out then, or if you check the pressure with the gauge, it's shot...replace it. If not, shut the main water valve off then open a water valve to relieve pressure in the system. Then, recheck the pressure in the tank. IF it's lower than when the water was on, pump it up to that value. Wait a bit and recheck it. If it holds, put the cap back on and turn the water back on and it's done. Seems like an easy job, and easy to avoid a service call that will probably cost at least $100. For that, if you don't have a quality tire pressure gauge or bike pump, you can buy one. If nothing else, the tire pressure gauge will be useful as you should check your car's tires periodically anyways. A quality gauge is a good thing to have.

 

[Diane18]

I have well water and a pressure tank. Yes, thermal expansion tank. Not installed yet. I still have plenty of hot water. Maybe the Ruuds were defective and the AOSmith just wasn't hot at 120. Someone told me there could have been an "air lock" in the system. All I know is hot water is wonderful!! Thanks for all the help.

 

[Reach4]

I have well water and a pressure tank. Yes, thermal expansion tank. Not installed yet.

You normally don't need to have a thermal expansion tank when you have a pressure tank. The pressure tank will absorb the thermal expansion.

The air lock thing is not a thing. If you had air, it would come out of the faucets. Maybe you had a stuck heat trap?

 

[Diane18]

Thanks on the thermal expansion tank info. Wonder why the plumber thinks I need one.

Interesting on the heat trap. Both times when the new Ruuds were installed the cold water intake pipe was super hot. Too hot too touch, not just radiant heat. That has not happened with the AOSmith. Also, when they released the cold water fitting to put the new hot water tank in, air came out of the old tank. Maybe normal, but plumber thought it was strange.

 

[Reach4]

Thanks on the thermal expansion tank info. Wonder why the plumber thinks I need one.

He is probably used to working with city water, or he had some memorable events when a thermal expansion tank was needed.

 

[Jadnashua]

Functionally, the pressure tank should work as your expansion tank MOST of the time. Code wants an ET between the cold supply and the WH without any valves between the two. So, there could be some situations where the pressure tank could not also perform as the ET for the WH.

If your T&P valve ever releases, it's probably one of those unusual situations where an ET, properly installed, would have prevented. They're not expensive, and depending on how fussy your inspector is, you may want to install one.

 

[Reach4]

Code wants an ET between the cold supply and the WH without any valves between the two.

You made that up.

 

[Diane18]

I'm in the country and my plumber typically works with rural clients. Yes, not expensive. No code out here, no inspections.

I do really appreciate all the feedback.

 

[Jadnashua]

Code says appliances and other products must be installed per the manufacturer's instructions (therefore, those indirectly end up part of the code). The majority of installation instructions call for the ET to be on the cold side without a valve between it and the tank either in their installation diagrams or text. The reason for this is so that it can always do its job. Put a valve of any type (shutoff or check) between the ET and the tank, and the ET cannot work if it's closed.

http://media.wattswater.com/2915054.pdf