Hi,


We have a weird problem with hot water running cold in our apartment. At all of the faucets and taps we only get hot water for a minute or two and have to turn off the faucet/tap for 30 seconds and back on again to get hot water. Then the same thing happens again.

To get continuous hot water in any of the hot faucets downstairs, we have to leave the shower faucet upstairs running on hot. In the bathroom downstairs, to get continuous hot water out of the sink, we have to leave the shower faucet downstairs running on hot. Whilst this is happening, the water coming out of the shower faucet is freezing cold. As soon as you turn off the hot tap in the sink, the shower faucet water warms up again. Of course, until it cools down because of the original problem.

We had a plumber come in and he thinks it is a cross connection and that the check valve was in the wrong position and ought to be located on the cold pipe closer to the water heater.

Here is a photo of our plumbing configuration next to our water heater:

http://www.flickr.com/photos/21503963@N04/5550135707/

On the far left is a 1/2 inch pipe, what we think is a return line. Next to that is the hot water pipe and to the right, the other pipe going in to the water heater is the cold pipe.

Now, behind the flue we have a check valve with an arrow pointing to the right ->, which is connected to the cold water line.

One last thing. The return line and cold pipe are warm if we don't run water for a while, but today I ran the hot faucet for a couple of minutes in the shower and went down to the basement to check and both the return line and cold pipe were freezing cold.

So... I'm wondering if this configuration is correct or if indeed the check valve is in the wrong place, or might need replacing? Could it be the mixing valves in the shower faucets?

Any advice much appreciated. Thanks so much! I am getting desperate at this point.

Cheers Mark. Much appreciated :)

Guys, I have added another couple of photos. This one is the on/off thing on the 1/2" line. I tried turning it anti-clockwise for ages, but it just kept turning and didn't seem to be going anywhere. Is it corroded?

http://www.flickr.com/photos/21503963@N04/5553644498/

This photo is a better view of the existing check valve behind the flue:

http://www.flickr.com/photos/21503963@N04/5553644136/

Any thoughts? Thanks.

Hi Kissifer...

Questions first... lots of questions, so bear with me, OK?

Is there a circulator associated with the "return line" coming from the left going into the cold water inlet to the water heater? Should be..?

You have a flow check and a backflow preventer coming off the cold water line going into the water heater and going to the right... is that for a boiler water feed, or what exactly is it for?

Did the plumber shut off the shutoffs under all the sinks to see if he could isolate the cross connection to the sink faucets by chance? If not, you could try to shut off the hot water shutoffs under all sinks with SINGLE LEVER FAUCETS and then run the showers. If the issue is fixed you would only need to turn the hot water shutoffs back on under the sinks until the problem showed up and then you would know the issue is at that particular faucet, right? If the issue was not fixed then the issue is most likely at the shower valves themselves and since we can't usually isolate the hot water feed into the showers it is probably just best to replace the mixer cartridge in these to be sure all bases are covered.

With all that being said, I can't say much more about the check valve issue as I am not clear exactly what that line is. You say it is a return line, but a return line would have a circulator associated with it... usually near the water heater, so I am a bit confused on that, OK?

The shutoff that continues to turn looks to be a gate valve. If it is a gate valve you could turn the handle 20-30 times until it seats or opens fully (I would open it all the way). If it spins past 30 times, it is defective and should probably be replaced with a ball valve... ;)

If when shutting shutoffs off under the sink the nut behind the handle starts to drip water just take two pair of pliers and hold against yourself as you tighten the nut behind the handle a 1/4 turn or so to stop the leaking. These nuts are called "packing nuts" as they are meant to be packed/repacked and tightened as needed... just some FYI!

Let me know more here, OK?

Mark

Mark, thanks so much for your answer and questions. To give you some more info (and excuse the terminology.. I am a novice!). From what I can see by the water heater, there isn't a circulator of any kind. Pretty much what you see in the photos is all we have. The green thing going to the boiler is a Taco boiler feed valve and behind the flue is a check valve on the 1/2" line pointing ->. To the left of the check valve is what I believe is the 1/2" valve to turn the thing on and off... I tried for half an hour turning it off and it just keeps twisting. My guess is it is indeed faulty.

As for turning off the faucets, I gave that a go (all of our sink faucets are two handles - hot and cold), but that didn't fix the problem with the showers. The showers are single handle Delta faucets. I also tried turning off the supply to the washing machine to isolate the problem (in the event of a faulty valve), but that also didn't fix it.

Interesting what you say about the return line. Not quite sure how to determine 100% if it is a return line, but I am pretty certain there isn't a circulating pump by the water heater.

Now, I have spent a fair while trying to diagnose this problem with you awesome experts and on another site, I was given the following advice by a couple of other really helpful plumbers:

"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."

So, not sure what you think, but any feedback you can offer would be much appreciated :) I think along with the above advice I will also have the water heater replaced and the flue pipe properly fixed.

Cheers Mark!

Did you mean for us to meet your friends and your foot? LOL Mark started this answer so I will defer to him.

Hi guys...

One more thing that I should have asked to start with... has this always been an issue since you lived here or is this a new issue? If it is an old issue then, most likely, we have a design flaw, right? If, however, this is a new issue then we probably have more of a defective part somewhere... make sense?

If we have a defective part then the design of the system can be dropped and no piping has to be changed... although if you swap out for a new heater I definitely want to discuss design here, OK?

Let me know the answer to my question and then I can present my final thoughts, OK?

I'll be back on later tonight (9:00 PM eastern time, or so)!

Mark

Haha. Good old privacy settings eh.

What's with the nasty looking bump?

Kissifer4- Did you solve this problem & can you share the solution?