Hot water in cold water lines?

[Roadman33]

I get hot water on both lines in the kitchen.
It seems to be hot at both supplies under the sink.

I recently drained the house water from the 2 lines going to the kitchen and when I was draining it had hot water coming out of the cold line too.

Is this broken check valve on water heater?

Ideas or ways to troubleshoot would be super!!

Thanks for your help!!

 

[Jadnashua]

The heat traps on the WH wouldn't be the source of hot in the cold line.

Do you have a hot water recycling system? That would have a check valve. The other common source of a hot water crossover is certain shower valves, but some single handle faucet valves can do it as well. If you have a shut off on your showerhead and leave the main valve on, that can cause it as can a defective washing machine.

While not likely in Seattle this time of year, if your pipes ran in the attic, they could get hot from the sun.

How hot is it? If you've just turned the heat on, and the pipe runs next to the heat duct, it could warm up.