Hot Water from Cold Tap

[Dave Armstrong]

About a year ago I had two old 50 gallon water heaters with new ones. The installer did two changes to the previous system. 1) He installed an expansion tank, and 2) he put the two water heaters in series (the previous ones were in parallel).

Ever since then we have experienced hot water coming out of our cold taps for the first little bit during usage. This happens for an especially long length of time in the morning.

Trying to troubleshoot this I have installed a check valve on the cold feed line before the expansion tank. I have also adjusted the water pressure in the house down from 75psi to ~50psi (the same pressure I measured on the expansion tank).

I still get hot water coming out of the cold taps.

Any ideas appreciated.

 

[Jadnashua]

It may have nothing to do with the ET or the water heaters...it could be your shower valve. Some, by no means all, shower valves and some single-handle sink valves can allow the hot and cold to cross-over between them.

It may also be that your ET is not sized properly for your system. There are a few ET calculators on the web. You might want to check on that to see if your ET is being overloaded after a large hot water use.

Just for clarification, you ET is installed on the cold water side of the WH, isn't it?

 

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[Smooky]

Is there a recirculating pump for the hot water? A picture of how the hot water heaters are plumbed might be helpful.