# Equalizing multiple units



## Bill (Jun 17, 2008)

OK, sorry I have not been on here much even to moderate, but work has me going 7 days a week with no end in sight. I told my boss the 15th of next month I'm going back out on my own. 

So, my first plumbing job will be to turn a 3 story building into 6 apartments, 2 on each floor with kitchen, bathroom, washer. Here is my delema. When I do multiple mixing valves in residential bathrooms I create a loop, this way the pressure is equal in all mixing valves. But, now on a much larger scale I want to assure equal pressure throughout all the units. I know I have to run 1" mains, then branch off to each unit with 3/4 lines, but to equal the pressure is it better to put the loop in the attic, second floor, first floor or basement? I am leaning towards running my 1" mains up into the attic, create a loop, then drop down to each unit. Any thoughts?


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## Tango (Jan 13, 2018)

In my neck of the woods I've never seen loops for cold water. Sometime on hot but only in highrise buildings with a pump. On a 3 floor building you'd never see that.


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## Venomthirst (Jun 20, 2018)

may need more info for ideas... Is hot going to be fed from central boiler or separate hw tanks.. with a building that small city pressure is plenty to feed .. hi rise depends on where boiler room is.. if its in basement your recirc is basically a booster pump.. if its on roof then cold water booster boosts pressure to get to boiler room then gravity builds pressure from top down... all depends on your setup lots of variables.


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## Tommy plumber (Feb 19, 2010)

Bill, why are you concerned about pressure? Is it that low in that area?


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## Bill (Jun 17, 2008)

It not low, but just want to be sure there are no problems. Never done multiple units before. Last thing I need is to start out with problems.


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## dhal22 (Jul 30, 2010)

I've serviced a customer in a 19 story (old) condo building where the water, hot and cold, drops from the attic. Of course it's pumped to the attic first.


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## GAN (Jul 10, 2012)

Take it all to the attic first, then down with pressure reducing valves. A three story your asking for problems either way when everyone uses water in the evening if bottom fed.

If you have minimal pressure your darn sure loosing you top floors.

Just another thought here. As I posted in an article Illinois will be moving away from master tempering valves period. That temperature range is prim temp for Legionella. Proven fact. When the new code comes out we should be looking at a minimum 160 water temp delivered to within 12" of the valve then tempered. Keeping the temp up is the only to control it.

Just a few weeks ago in St. Louis they shut down a Marriot (pretty sure it was them) completely evacuated it then flushed the lines since high levels were found


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## Bill (Jun 17, 2008)

GAN said:


> Take it all to the attic first, then down with pressure reducing valves. A three story your asking for problems either way when everyone uses water in the evening if bottom fed.
> 
> If you have minimal pressure your darn sure loosing you top floors.
> 
> ...


Sounds logical. Thanks


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## skoronesa (Oct 27, 2015)

Bill said:


> Sounds logical. Thanks



This sounds great as long as the pipes don't freeze in the attic.




.


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## GAN (Jul 10, 2012)

skoronesa said:


> This sounds great as long as the pipes don't freeze in the attic.
> 
> 
> 
> ...



Should say highest possible level while being safe against the possibility of freezing. :wink:


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## Plumbus (Aug 4, 2008)

Using the fixture unit table in my UPC book, I come up with 66 FU's. That's too much for a 1" service. Even sizing it using a Hunter Curve doesn't pencil out to 1".


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## justme (Jul 4, 2012)

1.5" to be comfortable


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