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Old 03-23-2011, 01:44 PM   #16
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Check valve positioning - is this incorrect and could it cause a cross connection?


To close, turn clockwise "righty tighty, lefty loosey" as it is a gate valve it will take many turns to close, the other valve you ask about is to isolate the HW tank.

When you turn the valve look at the stem below the handle, is it turning with the handle? It should be.

Mark

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Old 03-23-2011, 02:17 PM   #17
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Check valve positioning - is this incorrect and could it cause a cross connection?


Well, I turned it for ages and the stem was moving too, but still it keeps twisting. Also, I turned off the other valve and the handle above the green thing. I thought that might do the same thing as turning off the 1/2" line (prevent the water from going back up the cold pipe).

Aren't they supposed to turn off the cold water? I'm still getting cold water from the faucets.

Thanks.
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Old 03-23-2011, 02:24 PM   #18
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Check valve positioning - is this incorrect and could it cause a cross connection?


Mark, one strange thing. So it looks like I turned off the hot water by turning off those two other things (couldn't manage to turn off the 1/2" entirely). So, I went back to the bathroom and when I leave the cold water faucet running for a minute and turn it off, if I turn on the hot tap after that I get a short flow of cold water coming out. Is this just the nature of how things work or is there something wrong there?

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Old 03-23-2011, 02:31 PM   #19
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Check valve positioning - is this incorrect and could it cause a cross connection?


Yes by turning the ball valve (top one) you are turning off the cold water to what I presume is the boiler and the hot water tank, if you leave the upper one open and turn off the lower one you are turning off the HW tank,

Close down the 1/2" valve as much as possible, leave the others open and let us know how that works.

Mark
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Old 03-23-2011, 02:32 PM   #20
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Check valve positioning - is this incorrect and could it cause a cross connection?


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Originally Posted by Jackofall1 View Post
Yes by turning the ball valve (top one) you are turning off the cold water to what I presume is the boiler and the hot water tank, if you leave the upper one open and turn off the lower one you are turning off the HW tank,

Close down the 1/2" valve as much as possible, leave the others open and let us know how that works.

Mark
Alright, will give that a go

One other quick thing I noticed...

Even though the hot supply is off, if I run the cold faucet and then turn on the hot faucet the pressure of the cold water is greatly reduced. Turning off the cold and leaving the hot faucet on results in cold water still coming out until it is finished. Is that a bit strange?
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Old 03-23-2011, 02:37 PM   #21
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Check valve positioning - is this incorrect and could it cause a cross connection?


The 1/2" line is feeding both the cold and the hot, this is why you need to get that valve closed.

Mark
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Old 03-23-2011, 02:50 PM   #22
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Check valve positioning - is this incorrect and could it cause a cross connection?


I see. Man, I turned it clockwise for another ten minutes and still it keeps twisting. When I went downstairs the 1/2" and cold pipes were warm, but as soon as I reopened up the two I turned off I could hear water coming through the 1/2" and it went ice cold.

Also, what do you make of this behavior? In the downstairs bathroom if I run the hot shower faucet it stays scalding hot at first and if I quickly turn on the hot sink faucet during that time, the shower flow suddenly goes stone cold and the hot tap faucet stays scalding hot for ages. If I turn off the hot tap in the sink, the shower faucet gets it's heat again (until it cools down of course). Is this all tied in with the potential problem with the 1/2" line and check valve?
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Old 03-23-2011, 04:08 PM   #23
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Check valve positioning - is this incorrect and could it cause a cross connection?


Did you try turning on the water in the shower or wherever it runs cold and feeling the 1/2 inch pipe with the check valve in it and see if its warm meaning the check valve isnt working.
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Old 03-23-2011, 04:21 PM   #24
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Check valve positioning - is this incorrect and could it cause a cross connection?


When there is a higher demand (greater pressure drop) on the hot side the 1/2" line sees less flow, as the majority of the flow is bypassing going directly into the HW tank. Less flow from cold to hot = hot water at the HW taps.

You need to replace the 1/2" valve or the 1/2" check or both, to fix your problem, end of story.

Mark

Edit - find another plumber, $650 for that is rape!
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Old 03-23-2011, 05:37 PM   #25
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Check valve positioning - is this incorrect and could it cause a cross connection?


Jack, good advice. I'll get somebody else in to replace the 1/2" valve along with the check valve. You think the position of the latter is OK then, or should it be positioned above the 3/4x1/2 tee to prevent the hot water from traveling into the cold water system?

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Old 03-23-2011, 06:00 PM   #26
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Check valve positioning - is this incorrect and could it cause a cross connection?


When you get someone in there to do this, heres what I would be doing.

Disconnect the 1/2" line from where it is, pipe it to the HW tank drain, or just disconnect it and cap it, if you do go the HW tank drain you will have to add a "T" and a valve at that location.

The idea of a convection return line is cold water falls, and it should return to the bottom of the tank.

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Old 03-23-2011, 07:01 PM   #27
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Check valve positioning - is this incorrect and could it cause a cross connection?


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Originally Posted by Jackofall1 View Post
When you get someone in there to do this, heres what I would be doing.

Disconnect the 1/2" line from where it is, pipe it to the HW tank drain, or just disconnect it and cap it, if you do go the HW tank drain you will have to add a "T" and a valve at that location.

The idea of a convection return line is cold water falls, and it should return to the bottom of the tank.

Mark
I'd go a step further and replace the heater too. Didn't you sat its about 12 years old?
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Old 03-23-2011, 10:07 PM   #28
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Check valve positioning - is this incorrect and could it cause a cross connection?


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Edit - find another plumber, $650 for that is rape!
He obviously quoted to fix two problems. You have no idea what his overhead is, or where his shop is in relation to the job. He has gone out and diagnosed the problem already with 1 trip. Would you expect him to eat that trip, ESPECIALLY if the OP fixes it himself?

I don't know what kind of vent is on that heater, but from what I understand (we don't install much gas out here) that flue venting material is expensive.



O.P.

Definitely replace the check valve. It's a cheap part. cold water is following the path of least resistance if the bathroom you're having problems with is on the end of the loop the cold water will go there first before travelling all the way through the hot water loop if the check valve has failed. In a system where the recirculating system enters back through the cold nipple there should be two valves. The one already existing is ok, but there should be a check valve installed upstream of the tee on the cold supply.

Your gate valve is also obviously shot. If it is continuing to spin, it sounds like the gate inside has either completely rotted off, OR it dropped off the stem when you tried to close it, and you are no longer able to operate the valve. Replace it with a ball valve.
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Old 03-23-2011, 10:08 PM   #29
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Check valve positioning - is this incorrect and could it cause a cross connection?


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The idea of a convection return line is cold water falls, and it should return to the bottom of the tank.

Mark
Where does the nipple/dip tube on the cold side of a water heater lead to?
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Old 03-23-2011, 10:12 PM   #30
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Check valve positioning - is this incorrect and could it cause a cross connection?


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Where does the nipple/dip tube on the cold side of a water heater lead to?
You are exactly correct and thanks for that lesson, I wish I would have thought of that, but if piped to the drain you gain the vertical fall of the pipe external to the tank, which allows for increased convection effect.

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