Hot water recirculation?

[wpns]

I'm in a disagreement with a plumbing expert about how hot water recirculation systems work. While there are a _bunch_ of other issues, the zero-th one is how many bypasses there should be between the hot water supply and the return line. I think it should be at the end of the line (the faucet furthest from the hot water heater), he thinks (and specified, and the house was built such) that there should be a bypass at every single faucet in the house.

Am I completely missing something? Won't the first (and second, etc) faucet bypass too much hot water, so it'll take forever to get the hot water circulating out to the furthest one?

I'm not expert, but you know, physics, and fluid flow....

Thanks!

 

[havasu]

If your pipes recirculate in a circle, from the water heater, and back to the water heater, Unless this is a new build, most would not recirculate all the way to the faucet. If the loop was connected either in the basement or the attic, you would have instant hot water in just a few seconds. I would be satisfied completely rather then having three sets of pipes through every wall (Cold, Hot in, Hot out).

 

[wpns]

If your pipes recirculate in a circle, from the water heater, and back to the water heater, Unless this is a new build, most would not recirculate all the way to the faucet. If the loop was connected either in the basement or the attic, you would have instant hot water in just a few seconds. I would be satisfied completely rather then having three sets of pipes through every wall (Cold, Hot in, Hot out).

This is a new build. Not sure I understand the rest of your reply.

 

[havasu]

Are you recirculating your water using a bridge valve or looping the entire system?

 

[wpns]

Are you recirculating your water using a bridge valve or looping the entire system?

View attachment 34430

It's looping the whole system, from the hot water tank outlet, to each and every hot water faucet in the house, and then back through a common return line to the pump, and then into the bottom of the hot water tank. And it runs 24x7, with no thermostatic or timer cocntrol, which is a whole nother problem, but I'd like to focus on the 'each and every faucet in the house has a bypass into the return line' issue first...

Thanks!

 

[Twowaxhack]

I'm in a disagreement with a plumbing expert about how hot water recirculation systems work. While there are a _bunch_ of other issues, the zero-th one is how many bypasses there should be between the hot water supply and the return line. I think it should be at the end of the line (the faucet furthest from the hot water heater), he thinks (and specified, and the house was built such) that there should be a bypass at every single faucet in the house.

Am I completely missing something? Won't the first (and second, etc) faucet bypass too much hot water, so it'll take forever to get the hot water circulating out to the furthest one?

I'm not expert, but you know, physics, and fluid flow....

Thanks!

You don’t use bypass valves when you have a return pipe to the water heater.

Sounds like someone is using the wrong terminology.

 

[wpns]

Sounds like someone is using the wrong terminology.

I almost certainly am, as I'm not a plumber, nor do I know the correct terminology. When I said "bypass" (not "bypass valve") above, I meant a Tee in the hot water supply to a faucet (or shower, or clothes washer, etc) that connects directly to the return line.

What is that Tee called?

Thanks!

 

[havasu]

What is that Tee called?

Thanks!

A Tee?

 

[Twowaxhack]

I almost certainly am, as I'm not a plumber, nor do I know the correct terminology. When I said "bypass" (not "bypass valve") above, I meant a Tee in the hot water supply to a faucet (or shower, or clothes washer, etc) that connects directly to the return line.

What is that Tee called?

Thanks!

It would be called a “ tee “

The configuration would be a “ branch line “ and you’d need a balancing valve for each branch.

This is more common in large commercial buildings.

 

[Twowaxhack]

Most homes with hot water recirculation have hot water piping in series.

Hot water leaves the tank and flows to each fixture in series and at the end of the run there is a return line that returns the water back to the water heater.

 

[wpns]

Hot water leaves the tank and flows to each fixture in series and at the end of the run there is a return line that returns the water back to the water heater.

Right, and that's the way I understood these things were supposed to work. However, this one is plumbed with a "tee" at each fixture connected to the return line. Which is the part that seems wrong to me.

 

[MicEd69]

Most homes with hot water recirculation have hot water piping in series.

Hot water leaves the tank and flows to each fixture in series and at the end of the run there is a return line that returns the water back to the water heater.

Piping the hot water all in series will provide instant hot water at each outlet for sure. But if the hot water is piped in series, wouldn't a person in the shower get a burst of cold water when the washing machine comes on, or if someone is using hot water in the kitchen? Is this the tradeoff for instant hot water using that system?

Just wondering.

 

[Twowaxhack]

Piping the hot water all in series will provide instant hot water at each outlet for sure. But if the hot water is piped in series, wouldn't a person in the shower get a burst of cold water when the washing machine comes on, or if someone is using hot water in the kitchen? Is this the tradeoff for instant hot water using that system?

Just wondering.

Not a real problem if it’s sized properly and modern construction uses pressure balanced shower valves for protection against pressure fluctuations that can chill or scald.

I’d say 99% of all slab on grade homes here are piped in series.

 

[Twowaxhack]

Right, and that's the way I understood these things were supposed to work. However, this one is plumbed with a "tee" at each fixture connected to the return line. Which is the part that seems wrong to me.

Draw the piping diagram for us.

 

[wpns]

Draw the piping diagram for us.

What's an easy free tool for doing that? Something akin to KiCad or Sketchup?

 

[Twowaxhack]

What's an easy free tool for doing that? Something akin to KiCad or Sketchup?

Pen and paper then take a pic

 

[MicEd69]

Not a real problem if it’s sized properly and modern construction uses pressure balanced shower valves for protection against pressure fluctuations that can chill or scald.

I’d say 99% of all slab on grade homes here are piped in series.

Thanks for the explanation. Makes sense.

 

[wpns]

OK, here are some pictures of the drawings:



Does that clarify things? The two red lines are hot water supply and hot water recirculation return.

 

[Twowaxhack]

They show each fixture connecting to the return. I personally wouldn’t pipe it like that.

I’d just run a series loop then at the end of the loop have a return back to the water heaters

I hope it works after the plumber leaves.

 

[breplum]

As drawn is something I've never seen, nor done...but that's just my exp since 1975.
One big loop is what we normally do, or multiple big loops in different directions branched off a manifold with balancing valves.
As drawn is very odd.