Manifold at concrete slab. Can someone explain what this is?

[Steve DIYMan]

Hi,

Long time reader, first time poster.

I am remodeling my master bath. Have everything out, but haven't yet opened the floor to move the drains.

I don't understand what I am seeing re: the piping to the old tub/shower.

Here are images:

Why is the hot water (on right in this image) sent back into the slab in 2 different pipes? Are they feeds for other fixtures? If so why is there not a similar setup for the cold water?

Are these pipes most likely run under the slab or in the slab?

I know these might be hard questions to answers, but any guesses/wisdom appreciated!

Thanks,

Steve

 

[hj]

If you have not confused the hot and cold side, then the cold is the end of the cold water system, but it is the middle of the hot and the pipes are UNDER, not in, the slab.

 

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[LLigetfa]

One of the pipes might be a recirc return. If there is in-floor heating and no separate hot water heating system, that too could account for one of the pipes.

 

[Steve DIYMan]

One of the pipes might be a recirc return. If there is in-floor heating and no separate hot water heating system, that too could account for one of the pipes.

How can I determine if it is recirculating? There is only 1 pipe coming out of the hot water heater (if that makes a difference).

Thanks for the reply...

 

[Reach4]

How can I determine if it is recirculating? There is only 1 pipe coming out of the hot water heater (if that makes a difference).

Look for a recirculation pump. It would probably be near the WH.

 

[LLigetfa]

There is only 1 pipe coming out of the hot water heater

A recirc would go in not out and for sure you have to have at least two pipes that goes to the water heater. A recirc may be passive counting on convection so if there is no pump there should at least be a swing gate checkvalve.