Domestic hot water puzzle

coldupstairs

We had the reverse problem some years ago at a townhome we rented. We noted warm water coming from the coldwater faucets sometimes. The problem wasn't consistent, and we could usually eventually get cold. We knew it was interesting when very hot water came out of an outside hose bib one day. The problem was caused by someone installing the pressure reducing valve for the house in a location after the hot water heater had come off. Domestic supply pressure there was about 120 psi and the valve took the cold down to 50. But as has been pointed out, at every common outlet between hot and cold there was a path for the hot to backfill the cold lines based on the pressure difference. Obviously this doesn't relate to the situation of the original post, but you never know what you are going to find...

Dick Koral

DHW puzzle

The following Q was sent to the Supers Club Web site. It stumps me. It seems to stump the folks in Oregon, too. Here it is:

Hello,
I have a question that I feel is going to be nearly impossible to resolve.
Allow me to give you a bit of background first regarding the house.
It is a 1056 square foot home with 2 full bathrooms, a laundry room and of course a kitchen. The house is about 60 years old and the 2nd (master bath) and the laundry room were added on, I am guessing, within the past 20 years or maybe less. The laundry room and the master bath share a common wall, where all the plumbing is.

The hot water tank is actually inside its own enclosure, a closet like space, within the first (not master bath) bathroom. It has a sink and a tub.

We live in the Pacific Northwest where the average daily temp in winter is just above freezing.
There are 2 teenagers in the home.
Now to the problem.
Approximately 2 months ago, after one child would shower in the morning, (always in the master bath as the other had no shower) the second would complain that the first had used all the hot water....(this was a bit unusual, as the tank is I believe 52 (?) gallons and usually quite sufficient for 2 showers). Over a period of a month, the problem began to worsen, until one day there was no hot water at all in the master bath.
We began testing all the water faucets within the home and discovered that there was no hot water all the sudden now, in the shower of the master bath, nor in the sink in that room.
There was also no hot water in the sink of the other, older bathroom, but there is plenty of hot water in the tub in that bathroom. There is also no hot water in the laundry room but there is plenty in the kitchen.
Very curious, you think.
First we tried to reset the hot water heater. No change. We experimented. Thinking there was some sort of blockage between the hot water heater and those certain faucets, we shut the valve at the out put of the hot water tank. Then we proceeded to turn on the faucets, that are affected, one by one.... no water comes out when that valve is shut closed. When the valve is opened, the water flows and you can feel that it warms up maybe a degree or two warmer than the cold water.
We checked under the house for any signs of any leaks or flooding. Its dry under the house.
We went to the local plumbing supply store and asked... they were all stumped. A handyman happened to be there at that moment, and overheard the conversation, he was fascinated but is also stumped.
The hot water problem has not changed since the water stopped coming out hot in the two bathroom sinks, the master bath shower and the laundry room. There remains plenty of hot water to the other outlets.
I am a single parent and I do most of the home repairs myself. I have asked everyone and anyone that I can think of if they have any clues or suggestions. Nobody has been able to help.
That is why I am sending you this e-mail. I am hoping that you have some ideas or have actually seen such a strange problem and can tell me how to fix it. We have hooked up a temporary hand held hose type shower head in the original bathroom so the kids can shower, however this bathroom has no vent or heat, and has an unfinished wood framed window that is about 4 feet above the level of the top of the tub and moisture is collecting very rapidly and if I don't figure out this problem soon, the wood is going to begin to rot.
I would so appreciate any suggestions that you might offer on what to do or what to look for.
Thank you for your time
Peggy in Northeast Oregon

chuck shaw

my first thought

is some type of cross connection, could be at the washing machine. Look for a cross connection somewhere. Isolate the washing machine, and see if that helps. Then try to work at isolating any fixtures that share hot and cold. Close the valves under the sinks, try to cut in valves at the showers etc. There is always an answer

Chuck Shaw

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Big Ed

By-pass

You have a by-pass connecting the cold water line to the hot water line. Could be a facet , washer machine , hand sprayer with a shut off and the facet is left open or a potable dishwasher . You could check for a migration of hot water from the water heater to the by pass . Or shut off one by one and check if hot water flows . Water take the least resistant path .....

Bill_14

Questions

Has the water flow changed on the DHW side in the last two months? Has anything else changed besides a loss of hot water?

Mark Eatherton1

Dear Peggy

or is it ****, either way, the answer to the problem is quite simple. Get rid of the teenagers. I did, and my utility bill dropped by 50%! Unfortunatley, my cash flow out go increased by about 3,000 percent because they all went off to college at about the same time:-)

Your problem sounds as if you may have a cross connection between the hot and cold water line. This is a common occurence when there is a remote wand shower head that is kept in the off position at the shower arm with the Hot and Cold water valves left on.

It could also be caused by a cross connection at the automatic clothes washer. Make sure that there are no cross connections as explained above by making sure that the Hot and Cold water lines are kept closed at the autoclothes washer, and any showers with remote hand held wands.

Bear with us and we will find an answer to your problem.

Do that and check back with us.

G'Luck Peg

ME

Bruce_6

do they

have copper pipes or galvanized pipes, or a combination of both???

I have seen dielectric unions that were so badly corroded shut, that the hot water would not come out. I even have one sitting on my shelf that has a large rock jammed in it, completely blocking the flow! check the aerators, dip tube, and one more thing to check, is there a gate valve someone has shut off, the stems sometimes break off (handle just spins) and you cant turn it back on!

quite puzzling, but I am sure there is an explanation!

jim lockard

cross

Peggy --Had a simlar problem at an apartment house earlier this year. Tennants started complaining of no DHW I discovered a cross connect that was pumping cold into the hot. Took a good deal of snooping to find it. ? when you run the hot water place your hands on hot and cold pipes at water heater are they both cold or one hot/ one cold? Can you follow the pipes from the heater or do they go into the walls? If you turn off the cold valve under the sinks does anything change? The washer?

J.Lockard

hr

Got any Moen

single handle faucets or valves? They have been know to allow some cross over when the o rings wear or go bad.

Had to troubleshoot one of those in a hotel once

hot rod

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MikeB34

mixing.

Sounds like a mixing problem. A simple test. Turn off the feed at the Tank, and turn on a hot water tap. IF water flow without stopping, cold water is getting into the hot water system. If the taps in your home can be isolated, turn off the taps and the shut offs until the water stops. that is where it is mixing. Repair or replace. Don't forget the washing machine or any place that has both hot and cold water.
Murphy's law states tho that the tap you turn on is the problem, but you won't know that until you try all the rest.

If no water comes out when you try the aforementioned test, I would check the dip tube on the inlet side of the hot water tank. If it has cracked or broken off, it will cool the tank water quickly. Call in a pro to check this one as you will have to remove the inlet piping to the tank.

Good luck.

Mike

Tony_8

also

might be a tempering valve feeding a toilet leaking by.

Mark Wolff

Galvanized Domestic Water Piping

In older homes the piping was often done in galvanized pipe. The piping tends to corrode badly, especially on the hot water side.

It is possible that the corrosion slowly blocked off a branch section of your hot water piping that fed those areas.

Look or have someone look to see if your domestic water pipes are galvanized (even just in that area-sometimes in the older days they would switch materials midstream for no apparent reason).