# cross connection



## hottrodd (Nov 2, 2011)

I'm working in a mansion. The ladies having problems with all the water in the house being hot or at least warm. The house has 6 returns back to the heater. One return I couldn't get to heat up just warm. This is the area that's the problem I would think. I had problems with a faucet doing this once. 
Its going to take a bunch of investigation to narrow this down and try to isolate the issue. 
They also have the heaters cranked up. I need to turn them down a bit as well. 
Anyone else run into this problem before?


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## drtyhands (Aug 16, 2008)

What type of returns.
Balancers,Metlunds.
6 individual classic recirc pumps

Can you start shutting shut off heaters open a hot and listen for cross in single handle cartridges


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## hottrodd (Nov 2, 2011)

Its a single return pump. No balancers just throtling ball valves. Can u hear a cross connection?


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## HOMER (Jun 5, 2011)

moen cartridges ?

have you checked incoming water pressure ?

is return plumbed into water heater drain valve ?
possible restriction due to sediment,

tankless water heater(s)?


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## drtyhands (Aug 16, 2008)

hottrodd said:


> Its a single return pump. No balancers just throtling ball valves. Can u hear a cross connection?


Yes


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## hottrodd (Nov 2, 2011)

After visiting the house. I was able to trace back to 2 shower valves crossing. turned the stops off and had cold water again. Had to order a couple cartridges for tomorrow. Couldn't get cold water out of the 2 showers. Dialed the heaters down a bit. They were at 130. Have them at 112 now. There is no expansion tank at the heaters now and they are really pushing back on the cold. I'm going to suggest adding the tank.


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## HOMER (Jun 5, 2011)

shower cartridge replacement may not do the trick
you may need to replace the check stops if it's that type of device.

if there are separate volume controls attached to a thermostat mixer, than you replace or repair the check stops at thermostat, not the cartridge(if that makes sense)

spring loaded check valve usually built into shut off stops


also,odd that there are two defective cartridges on this job
have you identified the brand and model you're working on ?
are the defective showers controlled by a thermostat with volume controls ?
most of that high end stuff has built in and separate check device of some kind that is separate from the cartridge
good luck and
Merry X-mas


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## ibeplumber (Sep 20, 2011)

Had this happen before when a homeowner installed a off brand Moen 1222 positemp cart fron ACE hardware. Installed a Moen cart. and the issue was gone.


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## hottrodd (Nov 2, 2011)

I know it sounds strange 2 cartridges bad. They are in the showers that are used the most. Both showers would not run cold water. Water stayed the same temp in any handle position. Changed the cartridges and now there is cold warm and hot. This has been going on for a couple years. Its an awesome house though.


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## Widdershins (Feb 5, 2011)

hottrodd said:


> I know it sounds strange 2 cartridges bad. They are in the showers that are used the most. Both showers would not run cold water. Water stayed the same temp in any handle position. Changed the cartridges and now there is cold warm and hot. This has been going on for a couple years. Its an awesome house though.


 How close are the affected showers to the HW tank?

How does the return line return to the tank? Does it return to the cold inlet of the tank? Is there a check valve installed to prevent the return line from re-entering the cold water supply?


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## plbgbiz (Aug 27, 2010)

hottrodd said:


> Its a single return pump. No balancers just throtling ball valves. Can u hear a cross connection?


Throttling ball valves??? :blink: Please explain how you gauge said "throttling".

I don't get how a system with one water heater, one circulating pump, and *SIX* return lines ever worked. 

Maybe I need House Plumber to draw me a picture.


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## Widdershins (Feb 5, 2011)

plbgbiz said:


> Throttling ball valves??? :blink: Please explain how you gauge said "throttling".
> 
> I don't get how a system with one water heater, one circulating pump, and *SIX* return lines ever worked.
> 
> Maybe I need House Plumber to draw me a picture.


 You use check valves and ball valves on each return before it enters a manifold.

Check valves are to prevent the flow from the return lines from entering each other and the ball valves are used to balance the flow. I've had as many as 10 return lines on a single 3/4" bronze Grundfoss pump.

Works like a charm once you get all of the air out of the lines and properly balance the returns.

As for gauging, you can feel the difference in flow just by putting your hand on each individual return until they all match up.


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## plbgbiz (Aug 27, 2010)

Is that better than a single return from the furthest fixture?


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## Widdershins (Feb 5, 2011)

plbgbiz said:


> Is that better than a single return from the furthest fixture?


 Depends on the size of the house and how spread out the bathrooms are.


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## hottrodd (Nov 2, 2011)

No checks and no expansion tanks. Gave her a quote and recommended. Waiting on there decision.


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## hottrodd (Nov 2, 2011)

Widdershins said:


> You use check valves and ball valves on each return before it enters a manifold.
> 
> Check valves are to prevent the flow from the return lines from entering each other and the ball valves are used to balance the flow. I've had as many as 10 return lines on a single 3/4" bronze Grundfoss pump.
> 
> ...


Exactly what's installed. Exactly how I balanced it out. They really need the expansion tanks and check valve to get it right. We shall see.


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## Widdershins (Feb 5, 2011)

hottrodd said:


> Exactly what's installed. Exactly how I balanced it out. They really need the expansion tanks and check valve to get it right. We shall see.


Having that check valve installed before the return enters the HW tank will make a huge difference in how the system operates. It is essentially an open system that allows the hot water to re-enter the cold side without it -- Which renders the valves you installed to balance the closed loop worthless.

And yes, you definitely need an expansion tank, especially with the check valves installed and the desired operating temp.


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## hottrodd (Nov 2, 2011)

I agree. I stressed how important it is to the homeowner. Its working good right now except for a few seconds of warm from the cold. They may decide its good enough. I would love to finish it off right if they approve it.


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