Cold Water Pressure Loss - Domestic well

Seamus Farrell

Hi Folks,
I live in an area without a public water supply, so we have a deep well, a submerged pump and pressure vessel - I expect it's fairly standard set-up.
In the last week or so, we've noticed a problem with water pressure on taps connected directly from the cold water supply (as opposed to taps supplied from the attic tank). Every so often the pressure drops to a trickle. If you wait for a while, about a minute, the pressure recovers to normal, and stays OK for a while, before dropping again. There seems to be pressure in the pressure vessel, but when you connect a foot pump to the valve in the pressure vessel some water seems to come out of the valve. I think perhaps that the bladder or whatever it is inside the vessel that holds the air has ruptured. Does that sound like a reasonable cause for what we're seeing?
If that is correct, I'll bet the only solution is to replace the pressure vessel. Is that a job beyond the capability of a reasonably handy DIYer, and where would you go to get a replacement?

Seamus Farrell

Folks,

I have a correction to make to my post from a couple of hours ago. I checked the pressure vessel again and contrary to my description, water does not come out of the valve on the pressure vessel. However, when I as checking, I noticed that the pressure reading on the gauge I was using was higher than I expected - almost 5 bar, whereas I thought the plumber who fitted the system told me that a pressure of 2 bars was about right. (measured when the power to the pump is off, and the cold-water tap in the kitchen is run until the water stops.
Anyway, I let some air out of the vessel until it came back to a little above 2 bars.
Since then the problem may have disappeared . . .
I'll update this later when I've checked a bit more and am surer.

Sorry about the misinformation earlier.

Seamus Farrell

Folks,

My last post suggested that by reducing the air pressure in the pressure vessel to about 2 bar had possibly solved the original problem of intermittent complete loss of water pressure. Unfortunately the problem is still there. The only possible effect has been to increase the time it takes for the pressure to be restored after it fails.
Any suggestions about cause and / or solution would be really welcome.

kscobie

You need to see if there is any pressure in the vessel, and the only way to do this is to completly drain the vessel. Sounds like the membrane is porous, when you open the tap, you have no "reserve" in the vessel, and the pump is working straight away. If it holds no pressure, its cheaper to replace it, no fault with the pump id say