Recirculation Line

MJI22

Hi guys. I'm interested in putting a hot water recirc line in a restaurant because the water doesn't get hot fast enough. Can someone explain how I can do this? Thank you.

TheEplumber

It may not be your best alternative. Do you have a lack of hw in the restrooms? Consider an "on demand" remote heater. Sometimes with the existing piping a recirc will not help all fixtures.
Has this issue always existed- verify water heater is operating as it should first.
To answer your question as simply and short as possible though, hw leaves the tank, feeds all the fixtures then returns back to the cw inlet at the tank creating a loop. It also requires a pump and check valves to make the loop function

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MJI22

If the loop ties back into the cw inlet, where does the cold water supply tie in to? I'm replacing water heater with a new one already but a recirc line is requested.

TheEplumber

Here's 2 methods. 1 uses a modified drain, the other tees into the cold feed

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MJI22

Thanks, does the method that tees into the cold feed all the cold fixtures before returning to the heater? Do you recommend that method? I'd rather not run a separate return line if I didn't have to.

TheEplumber

Considering this is a public restaurant (the work should be permitted) and you're not familiar with a recirc design, I suggest you hire a plumber.

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MJI22

Oh, I see.

plummen

I generally use the lower right method myself,fewer parts only requires check valve

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techpappy

if you go with first option NO the return only goes to the hot water heater however not recommended as the cold water inlet should remain cold only to make sure the cold water drops to yhe bottom of the tank and is heated as it rises "circulation" Second method recommended. Just run common return from affected fixtures (sinks?) back to bottom of tank. You can remove the drain valve and install a tee at that point. Requires small recirc pump as well. Check with commercial suppliers for type and size. I have found that "Grundfoss" pumps are the best for this app. Of course there are other makes that will also work.