Check valve positioning - is this incorrect and could it cause a cross connection?

Alan · 03-23-2011, 11:12 PM

Ninja reply :

That gate valve is actually doing nothing now that i look at the other pictures. There is a ball valve above it that will shut off that whole line. You can replace it if you want to be able to isolate ONLY the water heater, but you can still shut the water off to it with the ball valve above.

What I would do in case you need to work on the check valve is to install a ball valve upstream of the check valve on that return line, so that you won't have to deal with drain down on that line in the future.

Alan · 03-23-2011, 11:14 PM

Quote:

Originally Posted by Jackofall1

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.

Mark

Isn't the elevation the same either way?

Jackofall1 · 03-23-2011, 11:16 PM

Quote:

Originally Posted by Alan

Isn't the elevation the same either way?

Now if you would have thought about that for just a couple of minutes you might not have asked that question.

What happens inside a HW tank, you know, that thing with a burner under the tank.

Mark

Alan · 03-23-2011, 11:20 PM

Quote:

Originally Posted by Jackofall1

Now if you would have thought about that for just a couple of minutes you might not have asked that question.

What happens inside a HW tank, you know, that thing with a burner under the tank.

Mark

Yeah like I said we don't do gas out here.

Jackofall1 · 03-23-2011, 11:29 PM

Quote:

Originally Posted by Alan

Ninja reply :

That gate valve is actually doing nothing now that i look at the other pictures. There is a ball valve above it that will shut off that whole line. You can replace it if you want to be able to isolate ONLY the water heater, but you can still shut the water off to it with the ball valve above.

What I would do in case you need to work on the check valve is to install a ball valve upstream of the check valve on that return line, so that you won't have to deal with drain down on that line in the future.

The gate valve is there to isolate the recirculation line, it needs to be there, the ball valve at the top is to shut both the HW tank and boiler feed water, this set up should be changed so they are seperated, the gate valve below the PRV is to isolate the HW tank, the 1/2" gate valve needs to be there to isolate the recirculation line, the check valve is to stop cold water from back feeding the HW line, which is currectly the problem.

By feeding the recirc line to the bottom of the tank the vertical column of cold water is increased, thereby increasing the effectivenesss of a natural convection recirc system. Putting the recirc back in the top of the tank is typical for a pumped recirc system, really not sure what the OP has here, and they aren't either.

Mark

kissiffer4 · 03-24-2011, 11:14 AM

Gents, thanks. I have another plumber coming in to take a look. Fair comment about the other quote Alan. Additionally, this is NYC after all

The guy I spoke with today suggested removing the 1/2" return line altogether and just putting in a circulating pump? Not sure if I quite have the terminology correct there.

Anyway, hopefully with a new check valve and new valve on the 1/2" line OR removing the 1/2" line altogether w/ a circulating pump will do the trick

COLDIRON · 03-25-2011, 08:45 AM

Quote:

Originally Posted by Jackofall1

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

Sounds like the way to go and replace the water heater at the same time with new valves and flue connections.
Separate the Cold water feeds to the Heating System and the Water Heater.

kissiffer4 · 03-25-2011, 09:28 AM

Gents, thanks so much for the all the advice. Before I started this thread I knew next to nothing about water heaters. Jackofall1, Coldiron, I am going to go with the original plumber who quoted me $1700 for the water heater replacement and have them do what you suggest with the 1/2" line at the same time.

A few quick questions. If they just cap the 1/2" line, will I lose some of the pressure for the 4th floor? My understanding is it provides some sort of service to give us better pressure upstairs. Is it worth asking them to install a circulating pump or is that just another headache? Lastly...will having the 1/2" line feed into the HW tank drain render it useless also or is this the better way to go to maintain the pressure upstairs?

Thanks!

Jackofall1 · 03-25-2011, 09:32 AM

The 1/2" line has nothing to do with adding pressure to the upstairs, it's intended purpose is to provide instant hot water at your points of use.

You really don't need a recirc pump for the above mentioned, natural convection will work, moving the line to the drain of the HW tank is just a better way to achieve the same thing.

Mark

kissiffer4 · 03-25-2011, 09:35 AM

Quote:

Originally Posted by Jackofall1

The 1/2" line has nothing to do with adding pressure to the upstairs, it's intended purpose is to provide instant hot water at your points of use.

You really don't need a recirc pump for the above mentioned, natural convection will work, moving the line to the drain of the HW tank is just a better way to achieve the same thing.

Mark

Mark, thanks for clarifying. So if I do that, is there any need then to replace the check valve on the 1/2" along with the 1/2" valve (blue twist thing) or will they effectively be useless? Do I still need to move the check-valve from it's current location to above the 3/4x1/2 tee to prevent the hot water from traveling into the cold water system?

COLDIRON · 03-25-2011, 09:37 AM

Quote:

Originally Posted by Jackofall1

The 1/2" line has nothing to do with adding pressure to the upstairs, it's intended purpose is to provide instant hot water at your points of use.

You really don't need a recirc pump for the above mentioned, natural convection will work, moving the line to the drain of the HW tank is just a better way to achieve the same thing.

Mark

"I second that"

kissiffer4 · 03-28-2011, 01:34 PM

Hi guys,

So I have somebody coming tomorrow to replace the check-valve on the 1/2" line and replace the broken valve to turn the 1/2" line on and off. Does that sound like a decent start? I figure at least if I can turn the 1/2" line off I'll be able to isolate it for further troubleshooting.

Thanks.

kissiffer4 · 03-29-2011, 12:13 PM

Well gents...one new check valve and ball valve later on the 1/2" line and the problem is fixed! Didn't need to move the check valve as now we have a working ball valve on the line I was able to shut it off, which appears to have corrected the problem.

Now...anybody know why shutting off the 1/2" line would fix this? Now I'm wondering whether I might need it for something else!

Thanks for all of the advice along the way