Can I manifold a recirc line?

[kiwifornian]

Will a hot water recirc line work using manifolds instead of one complete loop?

Run 3/4" out from WH to central area above all 3 outlets and a 3/4" return.
Manifold both the home runs to 3x 1/2" that go down to outlets and back up.
So essentially there would be 3 shorter loops.
But does the increase in combined pipe volumn in those loop matter?

Thanks.

 

[Breplum]

One giant loop is absolutely the best solution, case closed...
You have to be able to adjust flow precisely with multiple branches on a manifold.
The ideal and professional way is with circuit setters. For that you need test rig, but I suppose if you were willing to spend a lot of time you could try trial and error with circuit setters and no gauge set.

Pushbutton or motion sensor recirc is required for new construction in CA under Title 24. ACT D'Mand is a great mfr. for that.

 

[Sponsor]

 

[John Gayewski]

Why would you do this?

 

[Fitter30]

Could use a radiate heat manifold with built in flow meters. The other way is use globe valves for balancing in the bottom out the top with one size smaller valves. Using 1/2" 3/8" valves

 

[Jeff H Young]

3 loops as mentioned by kiwifornian might be plausible . especialy if its not a new build and you dont want to repipe the whole hot water system. I think you could get it to work well . You need a valve on each of the loops ( Ive only used circuit setters) . for an involved homeowner I dont think it would be that hard to dial it all in but for me to do it on a customers property I dont want to go out 3 or 4 times who knows maybe more trying to fine tune it but as a home owner making a few tweaks to the system ballancing it shouldnt be that bad.

 

[Jeff H Young]

Kiwifornian, I am interested to hear how it works out , What type valves you try and whether going on timer or how controling but three manual type valves is a good way . I definately think this might be worthwhile I cant say it always does because I dont know how its plumbed

 

[kiwifornian]

Why would you do this?

The thought was 1/2" down and up to each outlet is easier than 3/4" and less water to be heated. If I just tap of main line that's above and down to outlet there's 15 or so foot of water always cold in the branch so a waste of the water every time at every outlet.

 

[kiwifornian]

Will a hot water recirc line work using manifolds instead of one complete loop?

Run 3/4" out from WH to central area above all 3 outlets and a 3/4" return.
Manifold both the home runs to 3x 1/2" that go down to outlets and back up.
So essentially there would be 3 shorter loops.
But does the increase in combined pipe volumn in those loop matter?

Thanks.

 

[kiwifornian]

Thanks to all for replys.
If I understand it correctly, the capacity of the pipe run needs to remain consistent through out the loop.
Approximately, 3 x.5" is 30% more than the 1 x .75". The 3/8" would balance out closer, but I assume it needs to be exactish.
I am confused by the fact I have read it's fine for the return line of a complete loop to be smaller than the main feed line.
Have I misinterpreted that or is it the increase in capacity the issue or maybe the increase then the return to the 3/4"capacity?
Thanks again to all.

 

[John Gayewski]

The thought was 1/2" down and up to each outlet is easier than 3/4" and less water to be heated. If I just tap of main line that's above and down to outlet there's 15 or so foot of water always cold in the branch so a waste of the water every time at every outlet.

For this to make sense to me I'll need a drawing. Otherwise it's better to run one line.

 

[kiwifornian]

One giant loop is absolutely the best solution, case closed...
You have to be able to adjust flow precisely with multiple branches on a manifold.
The ideal and professional way is with circuit setters. For that you need test rig, but I suppose if you were willing to spend a lot of time you could try trial and error with circuit setters and no gauge set.

Pushbutton or motion sensor recirc is required for new construction in CA under Title 24. ACT D'Mand is a great mfr. for that.

For this to make sense to me I'll need a drawing. Otherwise it's better to run one line.

For this to make sense to me I'll need a drawing. Otherwise it's better to run one line.

 

[kiwifornian]

Would this work?
My desire is instant hot water with the least energy or water waste.
Walk up to kitchen sink, hit the switch for recirc and when indicator lite glows it hot. Turn off switch and open faucet. Switch could be countdown or automated, many options there but no real need.
Heated water is travelling only to the outlet. Not all the way around the loop back to the pump and temp sensor. It's seems to me a timer is a bit hit and miss and heating a large amount of water in a complete loop that you will never use, it just cools back down.

 

[Jeff H Young]

For me its real easy to picture without a drawing . a hot water system that tees off after leaving the water heater you cant just run a return from the farthest fixture. I just cant recomend specicaly where to run his new return lines from without a drawing but that dosent mean its not obvious to kiwifornian

 

[John Gayewski]

If your trying to balance the flow you'd pipe it differently. Seeing as your using valves you don't have to worry about that.

I guess when I asked for a drawing I should've been more precise. A layout of the plumbing fixtures would be more useful. Your plan is fine but if you think about it, the water will want to shoot through the middle of that arrangement rather than take the two wider paths, but like I said the valves take care of balancing.

I would encourage you to find a path that a 3/4" line can take where it passes by each fixture with a very short 1/2" leg to the fixture. This is better and less prone to maintenance with less valves. The short legs don't really have cold water in them because they are so short and the water conducts heat. The ONLY way I would use the arrangement in your drawing is if the fixtures where laid out in a way to make it either impossible or egregiously hard to do.

 

[Jeff H Young]

Wait a minute that dosent work your trying to save as much energy as possible you will have hot water at all three areas and you only want it at one place at a time. I thought you wanted hot water but you want it to be cold and then throw a switch which will heat three sections at once instead of just the desired one location getting hot ?
If we decided to plumb it the right way you would be disappointed that the entire hot water system was hot and theoreticaly wasting energy . I cant figure out the energy savings or begin to I was concidering comfort a bucnh of water savings and what I belive to be some heating costs

 

[kiwifornian]

If your trying to balance the flow you'd pipe it differently. Seeing as your using valves you don't have to worry about that.

I guess when I asked for a drawing I should've been more precise. A layout of the plumbing fixtures would be more useful. Your plan is fine but if you think about it, the water will want to shoot through the middle of that arrangement rather than take the two wider paths, but like I said the valves take care of balancing.

I would encourage you to find a path that a 3/4" line can take where it passes by each fixture with a very short 1/2" leg to the fixture. This is better and less prone to maintenance with less valves. The short legs don't really have cold water in them because they are so short and the water conducts heat. The ONLY way I would use the arrangement in your drawing is if the fixtures where laid out in a way to make it either impossible or egregiously hard to do.

Thank you John.
Hard to draw lay out.
Attic access and on a slab.
By cutting very little drywall and fishing through top plate it's very easy to get a path to each outlet. Horizontal drywall removal would be too extensive at this point
A complete loop with 8 ' of branches is what I'll probably do to keep it simple.

What I'm seeing with this whole recirc thing is, for comfort and water conservation I'll waste energy making hot water never to be used.
And saving energy on heating water means wasting water.
Balancing act.

 

[kiwifornian]

Wait a minute that dosent work your trying to save as much energy as possible you will have hot water at all three areas and you only want it at one place at a time. I thought you wanted hot water but you want it to be cold and then throw a switch which will heat three sections at once instead of just the desired one location getting hot ?
If we decided to plumb it the right way you would be disappointed that the entire hot water system was hot and theoreticaly wasting energy . I cant figure out the energy savings or begin to I was concidering comfort a bucnh of water savings and what I belive to be some heating costs

Heating all 3 outlets at once I see as an advantage as most likely all 3:get used in same small window of time. Morning and evening.
The total amount of water getting heated in the parallel drawing would be 65' of 3/4". -50' WH to manifold plus 15' to outlet.
A complete loop for me would be over 110' to last outlet if temp sensor located there, or 180' if temp sensor back at pump.
So I am not seeing your heating concerns as existing. A complete loop also heats every outlet does it not? Isn't that the whole idea of the recirc pump?
I never had to really think about one before, I am no plumber! They always sounded great and made sense until now that I go to put one in and I see many issues with energy waste. Like I said it seems like a balancing act between wasting water or wasting energy.
Because I live in a town prone to drought I guess waste the energy not the water.

 

[John Gayewski]

If your try to keyhole in a system that circulates then I could see doing it that way. It's not ideal, but no biggie really if it's what you want.

I've been working on two hotels recently. One piped with balancing valves one without. The one without its so much easier to work on. I can't shut the water off of the other one without shutting down the whole hotel. Check valves don't close all of the way over time in a hot water system due to mineral deposits, even ball valves that haven't been operated for ten plus years can break or fail to close completely.

 

[Jeff H Young]

I thought you were looking for some super energy efficient I agree with making the pump circulate all 3 lines at a pre set amount of return thats dialed in on start up and ajusted only if needed I dont think youll waste that much on heating the water. insulate where you can . Id say go for it youll probebly like it