View Full Version : Intermittent Hot Water

12-18-2004, 12:19 PM
I have an old 2 story house that was converted to 5 small units after WWII. My daughter and I live in 2 of the units. My 50 gallon hot water heater is about 8 - 10 years old. The house has 1 tub, 4 showers, and 10 sinks. Because of the conversion, the plumbing in the house as you might expect, is fairly complicated.

About 10 days ago I had the all of the accessible old iron water pipes in the crawl space under the house replaced with new copper pipe. The old pipes had mineral deposits that were impeding the water flow especially to the upstairs. The plumber warned me that because I was not replacing all of the pipes in the house, the increased presssure could loosen some of the deposits and cause an occluded pipe somewhere in the building. Since the installation the water pressure is vastly improved; there is still occasional 'sandy' debris and rustry looking water that comes out of faucets from time to time.

The real problem now is that the water stream from the showers sometimes is warm, then cold, then warm, then cold. At the same time the sink nearby will have scalding hot water (I have had to set the water heater temp quite high). At other times the showers will have very hot water as they should. Some of the sinks sometimes behave in the same way as the showers. The tub downstairs seems to always have hot water. Moreover, crazy as it sounds, I think that when the showers are behaving badly as described, and I turn on the water in the tub, the showers start to function correctly again, i.e., put out hot water.

The plumber seems defensive (this problem started right after the hot water pipes downstairs were re-plumbed). He says that the vent on my hot water heater was not installed correctly so maybe that is causing this (it never did before). So he will fix that and install a hot water recirculating pump. Then if that doesn't help, he says that maybe the tubes leading into the hot water tank have disintegrated and the hot water heater will have to be replaced.

I need help. I need to fix this. I have 2 tenants who are very upset about the lack of hot water (I don't blame them), and this is costing me a fortune.
Adding a recirculalting pump will help to get water faster, but it costs money to run, and doesn't seem to address the underlying problem, whatever it is. It seems to me that because sometimes the showers don't function properly and then, a short time later, they do, there has to be some sort of a valve involved.

Does anyone have any ideas? I would appreciate anything you could contribute to help get this problem fixed.

12-18-2004, 12:32 PM
I would guess that the shower valves are "crossing over".

Check to maker sure that there are no devices on the shower heads that stop the water. Sometimes people install these shutoffs at the shower head and leave the valvle (faucet) in the open position.
If that is the case, the water will cross through the valve and your temperatures will not be consistent.

12-18-2004, 12:32 PM
Since you did not do anything to improve the pipes in the walls, those may also be clogged, especially if you are getting debris from the faucets. If so, that can cause the symptoms you describe. I do not see how changing the vent on the water heater will have any effect. And since a circulation line will probably just keep the lines in the basement full of hot water, it also may not improve your problem.

12-18-2004, 07:24 PM
Thanks for your comments. Terry & HJ,

There was no work done on the shower heads other than to clear then of the debris that came through initially. So I don't think that any shutoffs were added/changed.

Are the shower valves near each shower? If each shower has its own individual valve set and all 4 showers don't work properly at the same time and then later all 4 work properly again, doesn't that indicate some sort of a single, more centrally located problem --than the odds that all 4 would clogg and clear simultaneously? Maybe there is something here that I don't understand??

Could there be some piece of debris at a central point (i.e., between the water heater and the offshoot pipe for the first shower in the system) that is acting like a valve? but that doesn't explain the change from warm to cold water flowing through when just the hot water has the problem....I would think that the flow would decrease and not just change to cold.

I just don't know what to think.