Latest Discussions : Plumbing


02:36AM | 04/01/03
Member Since: 12/01/02
93 lifetime posts
We recently bought a house that is on well water with pressure regularly between 35-45psi. There is an older water storage tank that resembles a Trident missle (not one of the small blue types). The hot water line then goes into an 'instantaneous' oil burner and from there into another storage tank. The previous owner said this tank was just a reserve. Coming out of this tank is a 1/2" pipe which leads into a 3/4" pipe to various parts of the house where it gets cut down to 1/2" again when going to faucets and fixtures. This itself seems like it could be a potential problem. I expect I should change this to a 3/4" pipe coming out of the tank but I don't know if it accounts for the problem I describe here.

Cold water is always very high pressure. Hot water is mild pressue and varies from day to day. When running hot water from any fixture in the house and turning on the cold water for even a second from any other fixture in the house, the hot water pressure drops to 0. I've heard of people turning on a cold water faucet and the shower gets hotter but this is the opposite. It seems there is a vacumn or something where whenever a second cold water faucet is turned on the hot water pressure drops.

A simple example is in the bathroom we turn the hot water on in the sink and when we turn the cold water on in the bathtub, the hot water in the sink stops flowing.

If anyone else has seen this or has ideas on what the problem could be, I'd really appreciate the input.

Thanks in advance.


04:08PM | 04/04/03
Member Since: 10/15/02
359 lifetime posts
And I thought I had problems! I think you need to do some remodeling of your plumbing. First get a larger storage tank, and boost the water pressure from your well. Mine runs around 60 PSI. Second, you will want to get all your supply lines equalized, going from 1/2 to 3/4 to 1/2 messes up things to the extent what your seeing now. Since your pressure is low, when you open the cold up, the hot supply doesnt have enough pressure to keep up with the cold. I have basically the same thing with an instant heater off the cold line at the rear of my house, which will soon be resolved when I replace all the pipes with a main run of 1" pipe and branch off of it to each faucet and heater. I will have 3 heaters, one for each bathroom and one for the kitchen. Currently I have a 3/4" supply to the rear of the house that supplies a heater and cold water for a tub, shower, toilet, sink and washer. The line comes off a 1/2" supply so when a cold faucet is opened the hot drops considerably, same as your seeing, but since my pressure is 60 instead of 35, I still get flow. What you basically need to do is get a full supply like 3/4" to 1" supply to your heater from the pressure tank, boost up the pressure a bit and you should be able to use both the hot and cold at the same time. Be careful boosting the pressure though, you dont know what shape the pipes are in, so maybe 5 pounds more than what you have now.


09:50AM | 04/05/03
Member Since: 03/18/03
20 lifetime posts

Part of the problem sounds like the tankless coil water heater in the boiler(I think that is what you described) is clogged from hard water. I would start by having the coil cleaned. It is normal with this type of coil to have lower flow from the hot water. But obviously not that low.


04:23AM | 04/07/03
Member Since: 12/01/02
93 lifetime posts
Thanks for the replies! It's starting to make sense.

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