I have a new (Jan '06) 55 gallon Marathon electric water heater in my townhouse. Works great except when showering. After about 2-2 1/2 minutes in shower, water starts getting cooler and cooler. If I turn the mixing valve more towards hot, the hot water returns but again only for a minute or two before if gets cooler again so I must repeat the process until my shower ends.

I thought the problem might be a faulty shower mixing valve so I recently replaced the 35 year old original one with a brand new Delta one. But the problem remains.

I have tested the sinks, both upstairs and down, and they do not seem to replicate the problem. The hot water stays hot in the sinks. So it seems that the problem is only in the shower. Any ideas on what I can look for or try to fix this annoying problem?

Before we take you in too many direction can you tell us how much water your shower head puts out? Most are now 2.5 gal/min and your tank can do that for a long time. Any chance your have a high volume head?

Run the hot water in a sink and let us know how long it takes before it runs cool. Did the problem start after the new water heater was installed or was it there before? I'm leaning towards a dip tube that has fallen in the tank or a faulty lower element but I don't have enough information to give a definite answer. Regards, Tom

Definitely not a high volume head. The shower head is an aftermarket massage type (mounted, not hand held) with a flow restrictor in it. Not sure of the brand.

Tom, I can't do the sink test for you as I am at home and won't be back to the townhouse for a couple of weeks. But the problem started right around the same time that the water heater was changed. I complained to my management company about it and they just turned up the thermostat setting but it didn't help. I thought it was a mixing valve problem and recently had the money to replace the mixing valve but it did not help the problem.

Quote:

---

Originally Posted by wvnh2

Definitely not a high volume head. The shower head is an aftermarket massage type (mounted, not hand held) with a flow restrictor in it. Not sure of the brand.

Tom, I can't do the sink test for you as I am at home and won't be back to the townhouse for a couple of weeks. But the problem started right around the same time that the water heater was changed. I complained to my management company about it and they just turned up the thermostat setting but it didn't help. I thought it was a mixing valve problem and recently had the money to replace the mixing valve but it did not help the problem.

---

Here's what I think has happened. The installer failed to prefab the cold water connect to the heater and soldered the pipe directly to the cold water inlet. The dip tube is plastic and is held on the inlet by a flare in the plastic tube. When the installer put heat from his torch on the cold water fitting he the flare melted and the dip tube slipped down to the bottom of the tank. The dip tube directs the cold water coming in to the bottom where it's heated by the lower element. If there's no dip tube, or it's not connected the cold water remains up on top where it's drawn into the hot water line after the first few gallons of hot water that was on the upper part of the heater. That's the only explanation that would cover your situation.
Have someone open up the cold water inlet. Have them bring another dip tube for a 55 gallon heater because it's my bet they're going to find that they need one. Good luck, Tom

Tom is good. I've run into serveral bad dip tubes that caused a problem like yours. I just never knew why they all failed.

I just wanted to update you on my situation. I emailed my management company a copy of this thread and asked them to check out the dip tube. They called me today and said the plumber took the cold water inlet off to check and found no trace of a dip tube. :eek:

The good news is that the electric company that we purchased the heater from is having a dip tube FedEx'd to me and they will cover the labor to install it (as they should!). So hopefully by the beginning of next week, the 2 1/2 minute hot shower will be nothing more than a memory.

Your advice was spot on. I don't think my management company would have had any idea what to look for without your input. Thank you so much for your help.