Removing hot water recirculating pump and return line.

[John JG]

I live in a 5 unit condo and we share the hot water heater with a circulating pump. The return line is made up of type M copper ( the thinnest type) and is under the slab foundation. When there is a pin pole leak on the return line, we need to jack hammer under the slab to access the leak. The recirculation system is very problematic. Is there a way to remove the return line under the slab or just not use the return line/pump all together? The pump is currently broken, unplugged, and every unit still gets hot water, so there is really no need for a recirculation system.

 

[Tuttles Revenge]

You should be able to locate where the line enters the slab at each end and cap those.. However, some return lines may have feeds to fixtures from them. I would install isolation valves in the places where you would cap the line and verify that everyone still has hot water with the lines effectively capped by valves. If everyone still has functional water, then the ends can be capped permanately.

Capping the line as close to the water heater return tee and as close to the point where the return line takes off from the "furthest" fixture would help eliminate as much of the worn out piping as possible.

 

[Sponsor]

 

[TheOverThinker]

[QUOTE=" Is there a way to remove the return line under the slab or just not use the return line/pump all together? The pump is currently broken, unplugged, and every unit still gets hot water, so there is really no need for a recirculation system.[/QUOTE]

Keep in mind, you may have a thermsiphon going, which is acting like a pump. Cold water sinks. hot rises, so a loop of pipe can well have
a full circulation without any pump at all.

The answer to "can I cap the return line" is "it depends on where the pipes go, post a picture".
Will capping break the thermosiphon? Yes. The end apartment will have cold water, or need to run the water to get it hot.

 

[John JG]

Thank you Tuttles Revenge and TheOver Thinker for your responses. Unfortunately, the return pipe is under the slab foundation, so I am not able to access the pipes to see where they go. It’s one of the main reasons I am trying to figure out if we can just do without the return pipe. The copper pipes are 40 years old and almost a liability having them under the slab. If we can’t access under the slab or don’t have a drawing/diagram of the plumbing of our building, is there still any other way to find out where the pipes go under the slab?

 

[Jadnashua]

A thermal camera might help locate where things go.

You might also want to check the local codes regarding the hot water recirculation. In some situations, they're required to minimize the wasted water while the cooled off water is purged from the pipes.

 

[Mliu]

If you are going to cut the recirculation return line out of the system, then you will need to find EVERY branch in every condo that ties into the return line and cap off the return AT EACH CONNECTION to the hot water line. If you do not, you will have long sections of dead-end piping (full of stagnant water) tied into the hot water lines. That's an environment ripe for Legionnaires' disease.