Baffling thing about water temperature

[phaeton]

In my apartment's bathroom, there is a standard sink with a standard- type Moen faucet. You lift up this oblong handle to open the water valve(s), and you regulate temperature by turning it counterclockwise (hot) or clockwise (cold). Pretty standard. Under the sink, I see the two expected water lines that go to little shutoff valves which lead into the wall. I can't see into the walls, of course, but I would assume that this faucet would be plumbed like anyone would expect.

So there's some bizarre things that will happen.

Scenario 1: I turn on the water, and what should be hot water (all the way counterclockwise) is ice cold. In fact, it is colder than the 'cold' water by about 20 degrees. Sometimes, if you reach over and flush the toilet, it becomes scalding hot until the toilet stops running, then resumes its ice coldness. Sometimes flushing the toilet has no effect. Eventually the hot water heats up, and usually the faucet acts like normal after that.

Scenario 2: I turn on the water, and it is scalding hot, even if I turn the dial all the way clockwise to make it cold. However, it remains scalding hot for about two minutes of constant running. Usually it will return to normal, but sometimes it will act as though the temps are reversed- hot becomes cold and cold becomes hot. After several minutes of running (and not touching the dial) the water becomes lukewarm and then returns to its previous temp. The faucet acts like normal after that, with the hot and cold on the correct sides and with proper control of the water.

Scenario 3: The faucet will periodically 'just work' like any other straight away. Hot is hot, cold is cold, and there is no temperature shifting.

I know that apartments are known for water temp/pressure issues due to many people using it at once. However, this particular building I'm in has only 8 units, and I can pretty much hear when anyone is using water. All three above scenarios happen at any given time of the day between 6am and 3am. There's no rhyme or reason other than one of the three scenarios *always* happen.

Since it is an apartment, it can probably not be fixed. But I am truly baffled by all this. Any ideas how this can happen?

thx

[Don Young]

Other than the "ice cold water", all of your symptoms are commonly found when a single valve faucet leaks internally between the hot and cold sides. Variation in pressures will cause the hot water to leak into the cold pipe at times. At other times the cold water will leak into the hot pipe. This can continue throughout a house, so that other faucets will momentarily get the wrong water temperature.

The solution is to correctly install a new cartridge or whatever the faucet uses to control the water, unless there is a defect in the body in which case replace the faucet. You can test this by turning off the water to only one of the supply lines and disconnecting the line. You will get water out of the faucet side of the disconnected line if the faucet leaks internally. It may not leak in all positions of the handle but there would be a position where it would leak without water coming out of the faucet itself.

Don Young

Don Young

[Marilyn & Bob]

It's not possible for the water to be 20° colder than the water coming into your house. So what you think is cold is actually 20° warmer than the water coming from the street. Completely consistant with the internal leak described by Don Young.

[Kevin Ricks]

In addition to a leaky cartridge there are other situations which can allow cold & hot mixing in the pipes. - A shower head that has a shutoff on the head and someone left the water faucets turned on with head turned off. - A janitors wash out sink where there is a garden hose with hand sprayer attached and valves left open.

- A faulty washing machine valve.

- Portable dish washer where the water line is attached to the kitchen sink faucet. There may be others.

Kevin

[trader4]

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Another possibility is someone in another apartment has one of the recirculation pumps installed to get hot water to their faucet quickly. These are small pumps that sit under the sink and when activated pump water from the hot line into the cold line until actual hot water arrives, at which point they shut off. Or are supposed to shut off at least.

[Sac Dave]

Another possibility is someone in another apartment has one of the recirculation pumps installed to get hot water to their faucet quickly. These are small pumps that sit under the sink and when activated pump water from the hot line into the cold line until actual hot water arrives, at which point they shut off. Or are supposed to shut off at least.

I think your thinking of an instahot (sp) witch is no more than a small water heater.mounted under the sink or lavi. A hot water loop is a loop that would start and finish at the main hot water tank . Basically it's a pump that circulates the hot water to each fixture. It would be piped to every sink feed by the hot water tank. Now there could be something wrong with a check valve causing some sort of problem . If there is one water heater all 8 unites then everyone should have the same problem.( could be a dedicated WH) But what's interesting it happens between 6am and 3am sometimes the recirculating pumps are controlled by a time clock so they don't run all the time so I would guess 6am to 3am would be peck demand.

[Sac Dave]

Another possibility scenario 2 The pipes are getting heating by outside temps especially if run in attic or exterior wall. water will come out hot when first turned on hot or cold then in a minute or two acts normal. If the problem seems worse on a hot day that's the cause. My house dose that now. If the hot water runs hot then cools, then the temp raises I would say that's your problem. It's hard to say exactly without seeing the system . Do you have your own water heater dedicated to your unite? If there is one hot water source for the complex are others having the same problem? Is there a hot water circulating system?