New Water Heater delivers cool water after 2 minutes

[naturemike]

Hi I recently bought a house with an old 2006 30 Gal water heater. It was turned up very high. Hot enough to burn so I turned it down. When I did so the hot water was good but it would run out rather quickly. I assumed it was probably sediment or element issue. Since the tank was old I decided to just have a new one installed. We now have a new 38 gallon AO Smith electric water heater set to 120 degrees. The water is nice and hot a first but it still gets cold after running the bath for about two minutes. The water heater is rated for 50 gallons but we cannot get anything close to that out of the tank.

I'm curious if anyone has experienced this issue before and how they solved it. Is it possible that there is some sort of weird plumbing issue happening or is it more than likely that we just got another bad unit? It seems strange that the new one is having the same issue that the old one had.

Any help would be greatly appreciated.

Thanks

- Mike

 

[Bob Reynolds]

It sounds like you might have too small of a water heater. You will need to turn the temperature up in order to be able to mix more cold water with the hot water. That will give you more gallons of water in the bathtub.

How big is the bathtub? How far is the bathtub from the water heater? All of this is a factor.

 

[bud16415]

Did you install the tank or was it done by a Pro?

A really good flow rate is a couple gallons per minute so running out of hot water in 2 minutes is not correct.

Was the new tank bled of air properly?

Also when you get it working correctly you could run it a little hotter than 120f.

 

[oldognewtrick]

Is there a chance it's hooked up bachwards?

 

[naturemike]

It sounds like you might have too small of a water heater. You will need to turn the temperature up in order to be able to mix more cold water with the hot water. That will give you more gallons of water in the bathtub.

How big is the bathtub? How far is the bathtub from the water heater? All of this is a factor.

The bathtub is very close and I'm only getting about 10 to 15 gallons out of this unit. It's not even close to filling the tub

 

[naturemike]

Did you install the tank or was it done by a Pro?

A really good flow rate is a couple gallons per minute so running out of hot water in 2 minutes is not correct.

Was the new tank bled of air properly?

Also when you get it working correctly you could run it a little hotter than 120f.

I hired someone to do it but their work seems to be a little shotty. I do not know if it was bled of air properly.

 

[naturemike]

Is there a chance it's hooked up bachwards?

I just checked and it is hooked up correctly

 

[oldognewtrick]

If you have a multi meter, check and see if you're getting power to the bottom heating element. It will activate after the top element turns off. If you are not comfortable checking electrical, call a professional.

 

[Annapolis Albert]

If you comfortable around electricity you could also measure the current the heater is drawing. If it is not drawing the rated amps when the water is coming out cold then you will know it's an electrical problem. You will need an amp clamp. They are actually quite affordable from places like Home Depot, Princess Auto or I imagine Harbour Freight. If you have the lowboy 38 gallon heater it is rated at 4500 watts. We have a similar sized heater with no issues.

 

[user 4883]

Sounds like the unit was installed without a dip-tube. Wouldn't be the first one i've seen like that.
Last one, I called the manufacturer and they sent one to me overnight, free of charge.

 

[BuzzLOL]

Yes, a dip tube takes incoming cold water to the bottom of the tank to be heated while hot water is drawn off the top of the tank... don't want incoming cold water going right over to the tank outlet...