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kissiffer4 03-16-2011 02:53 PM

Cross connection problem?
 
Hi all,

Hope you don't mind me starting a new thread for this particular issue. We have a hot water problem in our apartment from various faucets (hot water going cold) and after investigating, here is an outline of the various scenarios:

* turn shower faucet upstairs on hot - water comes out hot then goes warm - i leave this running for the entire test below

* turn on bathroom shower faucet downstairs on hot - remains very hot whilst shower faucet upstairs is running - shower faucet upstairs goes cold

* turn on bathroom sink faucet downstairs on hot - remains very hot whilst shower faucet upstairs is running - shower faucet upstairs goes cold

* turn on kithcen hot water faucet downstairs - remains very hot whilst shower faucet upstairs is running - shower faucet upstairs goes cold

* as soon as I turn off the faucet upstairs, all of the faucets downstairs cool down and I have the same problem as before - hot water cooling down.

Only other thing to add is, if I put the washing machine upstairs on a cold cycle, then whilst it is filling with water, the water from the faucets downstairs all remain hot (when turned to hot).

Question: Is this a cross connection problem? Could it be the hot water heater failing? Or, might it be a problem with the washing machine?

Any other suggestions much appreciated.

I have a plumber coming tomorrow to take a look at the washing machine (and do a test by turning off the machine valves).

Thanks all. Apologies for going on about this.

AllanJ 03-16-2011 04:14 PM

Do the test with the washing machine faucets shut off -- yourself. (save the plumber's charge.) (Try all the other faucets to see if you still have problems.)

Most likely it is the washing machine.
Most likelty it is not the water heater.

The washing machine wall faucets should be shut off all the time when the washing machine is not in use. Flooding from burst washing machine hoses ranks high on the list of common insurance claims.

kissiffer4 03-17-2011 02:16 PM

OK, so did the test with the washing machine (turned off the valves), but no luck, still the same problem.

One other thing, I found that if I leave the shower faucet running on hot in the downstairs bathroom and turn on the hot tap in the sink, the tap water runs continuously hot, whilst the faucet water goes cold. As soon as I turn off the faucet, the sink tap water goes warm (and the same problem returns).

Any thoughts?

AllanJ 03-17-2011 06:55 PM

Next place to check for trouble, the upstairs shower faucet. Is this a single handle for both hot and cold?

Take the front cover (the escutcheon) off. (May need to take the handle off first). Are there screw adjustements that will turn off the hot and cold water supply respectively to the shower faucet unit? Or is there a removable panel on the other side of the wall where you can see inside for shutoff valves for the shower similar to the shutoff valve under the toilet or sink? Turn off the cold shutoff and see if the problem goes away (except for no cold water at the shower faucet).

kissiffer4 03-17-2011 08:11 PM

Hi Allan,

Thanks for the feedback. So, the guy opened up the shower control unit today (it is an old Delta unit) and he couldn't see a way to shut off the valve. It looks something like this:

http://www.terrylove.com/forums/atta...achmentid=9577

Not my unit, but similar. So, all he did was replace a rubber bit and spring inside the control unit, but that didn't make any difference to the problem. We couldn't see the valve, but do you think they might be located elsewhere on the pipe? Next thing he wants to do is open up the wall behind the shower to see if he can spot anything.

Thanks again for your advice. Much appreciated.

AllanJ 03-17-2011 09:20 PM

If there is no trap door behind the shower or on the ceiling below then chances are there are no shutoff valves. If you have the wall cut open then you should have a set of shutoff valves installed so next time you can turn off the shower unit for repair without having to turn off all the water in the house.

Then have a framed trap door put where you cut the wall open instead of plastering it over again.

Dougtheplumber 03-17-2011 09:58 PM

Is there a recirculating pump on the hot water in the building, this would usually be tied into the hot water line at the farthest point and tie back into your cold water line just before it enters the water heater, it will have a pump on the line with the flow into the water heater and a check valve to prevent this problem you are having.
If there is a pump, find an isolation valve on this line and close it, then repeat the steps above. If this solves the problem then you have a faulty check valve and possibly a weak pump.

kissiffer4 03-17-2011 10:07 PM

Gents, from what I can see at the water heater there isn't a recirculating pump. We have one of these from the cold water line to the boiler:

http://www.pexuniverse.com/store/pro...ler-feed-valve

That is about it though.

Just to add, we are the 3rd & 4th floor of a walk-up brownstone and the water heater is in the basement. Each unit has their own water heater (3 units in total).

Is there anything to be gained from this guy opening up the wall behind each of the shower fixtures (in both bathrooms)? He said he wants to check the pipes, but quite sure why.

Anything else that could be causing this? Alan, I guess since it sounds like we don't have a shut-off valve on the showers it is going to be difficult to isolate.

One last question...if it is a cross connection of some kind, how will the plumber be able to identify and fix it? I have tried shutting of the valves under the sink in each bathroom (hot and cold), but that didn't make a difference in terms of fixing the problem.

Thanks so much.

Dougtheplumber 03-17-2011 10:35 PM

Shut off the hot water valve on top of your water heater so there should be no hot water to the house, then open up each hot water tap one at time, if you get any water then you have a cross connection.

the_man 03-18-2011 12:23 AM

Quote:

Originally Posted by Dougtheplumber (Post 611646)
Shut off the hot water valve on top of your water heater so there should be no hot water to the house, then open up each hot water tap one at time, if you get any water then you have a cross connection.

just to clarify... you'll probably get water b/c of whats in the lines. check your meter to see if you have flow and feel the water line to the HWT to make sure the valve works right

kissiffer4 03-18-2011 08:11 PM

theman, this might be a stupid question, but when you say " check your meter to see if you have flow and feel the water line to the HWT to make sure the valve works right" - what is the correct behavior if I shut the hot water valve off? I shouldn't get any sort of flow right?

Fellas, one last thing. In the kitchen downstairs, we have a dishwasher. When we start that thing, all of the hot faucets run cold. Could it be a cross connection at that point?

Here is a simple layout of our apartment.

bathroom - 4th fl
kitchen | bathroom - 3rd fl

Thanks.

the_man 03-18-2011 08:38 PM

Quote:

Originally Posted by kissiffer4 (Post 612195)
theman, this might be a stupid question, but when you say " check your meter to see if you have flow and feel the water line to the HWT to make sure the valve works right" - what is the correct behavior if I shut the hot water valve off? I shouldn't get any sort of flow right?

Fellas, one last thing. In the kitchen downstairs, we have a dishwasher. When we start that thing, all of the hot faucets run cold. Could it be a cross connection at that point?

Here is a simple layout of our apartment.

bathroom - 4th fl
kitchen | bathroom - 3rd fl

Thanks.

If you are on a municipal water system, you can look at the meter to see if any water is flowing thru it. Most meters have a small dial that moves with the smallest trickle of water. I say feel/listen at the shut off to the HWT b/c the valves don't always work. You might think you have it off, when in fact a small amount of water is trickling by. The dishwasher won't have anything to do with a cross connection, it only uses hot water. any single handle valve could. so when the water is off to the tank and you still have water flowing out of the hot side, you can turn off the angle stops under the faucets to try to determine which one is the problem.

kissiffer4 03-18-2011 08:45 PM

Thanks. I'll take the dishwasher out of the equation then. So, if I shut off the water heater (it's in the basement) and hot water is still coming out of any of the hot faucets in the bathrooms/kitchen, does that mean I have a cross connection at that point, or does it mean the valve on the water heater is faulty?

One last thing, when I checked the water heater the other day, the cold pipe from the heater felt warm. After running the cold shower faucet upstairs again (lots of running up and down stairs) the cold line to the water heater was cold again. Is it odd that the cold water pipe was warm to begin with?

Cheers.

AllanJ 03-18-2011 08:58 PM

Quote:

Originally Posted by kissiffer4 (Post 612217)
of the hot faucets in the bathrooms/kitchen, does that mean I have a cross connection at that point, or does it mean the valve on the water heater is faulty?

One last thing, when I checked the water heater the other day, the cold pipe from the heater felt warm. After running the cold shower faucet upstairs again (lots of running up and down stairs) the cold line to the water heater was cold again. Is it odd that the cold water pipe was warm to begin with?

Cheers.

If no one hs been using hot water for awhile the cold pipe just at the water heater could get warm for a foot or so because the hot tank metal conducts to the pipe metal.

Also water expands when heated. Some water may have been pushed back out the cold line this way.

We have not proved or disproved cross connection at the shower faucet upstairs. You will need to find or install shutoff valves (angle stops) for that faucet before we can prove or disprove corss connection there.

kissiffer4 03-18-2011 09:28 PM

I just tried a quick test by turning off the valves under the bathroom sinks and tested the other hot faucets, but the problem still exists.

Tomorrow I'll try turning off the hot water feed to the water heater then see what is still running from the hot water faucets.


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