New Navien Tankless. Cold line feels hot and hot line feels cold.

[jag2k2]

I hired a plumber to install a Navien 240a2. When I run the hot water in one my showers or faucets and then inspect the unit, the line labeled "HOT" feels cold and the line labeled "COLD" feels hot to the touch.

The red valve is connected to a terminal that is labeled HOT

The showers and faucets are behaving normally (hot water is coming out of the sides I'm used to). If I didn't know any better I would say that water is flowing through the navien backwards. Is that even possible? Did my plumber just swap the hot and cold lines to the house?

 

[WorthFlorida]

There seems to be a tee of sorts.The hot side usually would not have a shut off. Only you can tell how the house is plumbed for COLD and HOT. Follow the cold water pipe from the meter or house entrance.

You have a re-circulator? If it is a two pipe system, the cold is used for the return. It's hard to tell if anything is connected to the RECIR connection. It doesn't look like there isn't one.

See page 25. The blue PEX looks like it connected to a pressure relief valve where it must be discharged within 8" of the floor or drain.

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[Breplum]

Should not be doing what you describe. Something is WRONG. Call the plumber back.

 

[joseph miller]

If you have copper piping, you may notice that the copper pipes are getting a little bit warm. Because they are good conductors of heat, this is something that is considered normal as well.
If the entire cold water line is getting hot, this is not normal. May be the backflow-preventing valves got damaged or you should add one externally to prevent the backflow(temporarily). You should contact a certified professional to repair it.

 

[joseph miller]

If you have copper piping, you may notice that the copper pipes are getting a little bit warm. Because they are good conductors of heat, this is something that is considered normal as well.

If the entire cold water line is getting hot, this is not normal. May be the backflow-preventing valves got damaged or you should add one externally to prevent the backflow. You should contact a certified professional to repair it.