Crossover connection on outlet of water heater?

[justlen]

Hello;

A friend of mine just bought a house with a Navien NPE 240 S2 tankless heater. Since I have an A2 he asked me about recirculation (his wife is beefing about time to heat water). I explained that I had an A2 and the water recirculates via a crossover valve at the furthest point (NaviCirc).

Since he has an S2, with no recirc pump I went over to look at it, and at the outlet of the water heater I found these strange connections.

There are two of them, both cross-connecting the hot and cold. The outlet line (at the top) continues up into the ceiling and follows the main hot and cold lines respectively. Each one has a cap on one side of the manifold (or whatever it is).

Is this some sort of recirculation setup? Should I be searching for a recirculation pump somewhere in the house?

Thanks for any feedback to enlighten me. If we get stumped he'll call in a proper plumber to set some sort of recirculation, but before that I want to make sure there wasn't what used to call in the Navy a "DFU" (dumb f**king user) issue here.

 

[Reach4]

Thermal mixing valve to limit the temperature of the water going out to the sinks, shower, tub. Typically 120F.

 

[Sponsor]

 

[justlen]

Thermal mixing valve to limit the temperature of the water going out to the sinks, shower, tub. Typically 120F.

If so, why one on both the hot and cold? I can understand mixing cold into the hot but the other way around?

 

[Reach4]

If so, why one on both the hot and cold? I can understand mixing cold into the hot but the other way around?

I maybe misunderstand your description. Normally there would be one device that would connect to both hot and cold. I would guess the cold is the left of your photo, and the cold water from the street/well would come in from the top left.

So as I picture it, cold comes from above left, and splits to go down into the WH and right across to mix with hot coming from the right. Mixed water would go up from the center.

 

[Fitter30]

If so, why one on both the hot and cold? I can understand mixing cold into the hot but the other way around?

Never seen one like this one. The back side look the same as the pic. Normally there is a adjustable bellows to change mix water set point. Has both internnal and external recirculation.

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