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 Water Heater - Replaced everything still cold?!
Author: dch27 (WA)


We've been having some problems with our hot water. Over the last few weeks we've noticed that the water doesn't get as hot or last as long. Finally it got to the point that the water barely got lukewarm.

The water heater is electric, made by AO Smith. I went ahead and replaced both heating elements and both thermostats. The problem remained. I did some more research and found that it could be the dip tube. I replaced the dip tube today, and we are still having the same issue. I have no idea what it could be.

When I replaced the dip tube, I couldn't get it out. While trying to pry it out the flange simply tore off and the tube fell into the tank. The dip tube that I got from the store was long. I put the tube in until it hit the bottom of the tank. I backed it off a few inches and cut the excess length off of the bottom end.

Once I replaced it, the water seemed to be getting hot, and then very shortly after it was freezing. I have both thermostats set at 120°. Both heating elements read 15 ohms. I confirmed that the lower element turns on when I lower the upper thermostat. It seems like once I turn on the hot water, everything goes from hot to warm to cold pretty quickly.

Could I have installed the dip tube incorrectly somehow? Could I have not cut enough off of the end? If everything I've replaced was installed correctly, what else could it possibly be?

Thank you for any help!

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 Re: Water Heater - Replaced everything still cold?!
Author: Paul48 (CT)

A bad thermostatic mixing valve? A cross-connection? Bad check valve on a recirculation pipe?

Edited 1 times.

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 Re: Water Heater - Replaced everything still cold?!
Author: hj (AZ)

Could be several possibilities, including a broken pipe under a concrete slab, which is most likely from your description, but would have to check everything else to be sure.

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 Thanks for all of the feedback :thumb:
Author: dch27 (WA)

Thanks for all of the feedback.

I have some additional information...

We woke up this morning and we were able to get 2, pretty miserable lukewarm showers. The change from hot to warm to cold is longer than I let on in the previous post. My wife was doing laundry last night so that could be why we were seeing the abrupt change.

The Water Heater is an AO Smith, Model: ECRS 50 200. Serial number H04J043512. I believe the MFG date is 2004. (12 years old)

Another piece of information - when I replaced the dip tube, the dielectric pipe nipple available at the store was way too short. I ended up using a regular old galvanized steel pipe nipple while I waited for a longer dielectric nipple in the mail. I didn't check this, but perhaps the I.D. of the pipe nipple is larger than the O.D. of the dip tube shoulder, and there is no seal between the dip tube and the tank? Perhaps that is wishful thinking, but the new nipple should arrive today and I can at least check.

I think anything other than what I've already done is outside if my expertise. I sure hope it isn't a broken pipe. I can't even imagine how much that would cost to fix. There is no noticeable difference in water pressure - hopefully that isn't it.

We are going to contact a plumber today, hopefully the water heater is just fried and I need a new one.

I'll keep everyone updated - please let me know if there is anything else I should check while I wait for the plumber.


Edited 2 times.

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 Re: Water Heater - Replaced everything still cold?!
Author: packy (MA)

post a picture of the water heater and the piping around it.

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 Re: Water Heater - Replaced everything still cold?!
Author: dch27 (WA)

So I went ahead and bought a new water heater. we were going to replace it this evening. Last night I was in the garage preparing to clear space, and I heard a hiss behind the furnace. I hadn't heard it before, probably because the heat has been on pretty regularly.

I shut the heater off and took a look behind the furnace. There is a small trench, and it is clearly damp. The hiss is emanating from there. I turned off the water outlet from the water heater, bled the lines of all air, and the hiss went away....

So there is a hole in something underneath my slab behind my furnace. I can't see any water spraying, but it is clearly wet.

It is odd that there is already a mini trench there - perhaps there was some work done there already.....this is miserable.

Post Reply

 Thanks for the suggestions :thumb:
Author: dch27 (WA)

I figured I would let everyone know what happened.

Water heater is fine.

There was a leak in the pipe, and of course the pipe was under my furnace. The bottom plate was cut out from my furnace and you could see the pipes, just sitting there - not under concrete. The builders simply put the pipes in, put the furnace in, then poured the concrete for the garage.

It wasn't a cheap fix, but its done.

Thanks for the suggestions.

Edited 1 times.

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 Re: Thanks for the suggestions :thumb:
Author: brentspears (GA)

I too have an AO Smith and am having the opposite problem ... Water gets too hot and trips the reset button. I have tested the thermostats and elements and all checkout as ok. I do not have a furnace in the garage with it so I don't think it is a pipe issue. But your post gives me hope I am not alone with a mysterious hot water heater.

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