What ho one and all,

The mains water incoming is of course, 32mm and around 6 bar. It goes via a PRV (reduced to 3 bar) to a water softener for both hot and cold. All the pipework is 22mm, reduced to 15 at the various taps and with the flexible tails and mixer taps, reduced again to around 10mm.

Cold water to the baths, showers and utility room is soft; to the kitchen sink and washbasins, it is mains hard (nicer taste!) Hot water is stored in a 300 litre cylinder and is piped to all outlets in 22mm (then 15 and again, the flexible tails, around 10mm.)

From the get-go, when one hw taps is running, a second has reduced pressure, but recently, there seems to have been a very noticeable change.

Open any hw tap and the flow is pretty good but within seconds, the pressure ;reduces and the flow is pretty much, a trickle. So much so that the pressure valve on the shower will not stay on the shower setting.

This is a video of what is happening; I don't understand why or how to fix it. The hw pressure/flow has never been great but it was OK, now it is tending towards unacceptable.

Grateful for you thoughts.

(PS I have tried to upload an mp4 video but don't think it is possible. Is it possible?)

Posted By: Rexto the kitchen sink and washbasins, it is mains hard (nicer taste!)

and won't leach the calcium out of your bones.

I thought one of the purposes of softened water was to prevent (reduce) furring.

And never heard of a 'paste site.' Can you recommend one?

Posted By: RexAnd never heard of a 'paste site.' Can you recommend one?

There are lots, but https://pasteboard.co/ is fairly simple to use. Just tell it where the picture is on your disk and upload it, then make a note of the URL it displays and paste that URL here.

Posted By: WillInAberdeenThe hot water cylinder has an expansion vessel with a rubber bladder in it filled with air or nitrogen. This maintains pressure as the water gets hot and expands, and also when water is being run off quickly.

The bladders burst after some years and then the vessel needs replacing.

You can turn off the mains water supply and run the hot tap until zero pressure and water stops coming out. Then check the pressure on the valve of the expansion vessel using a car tyre pressure gauge. It should remain around the supply pressure, which sounds quite high in your case.

Then turn the mains back on and check the pressure reading stays roughly the same both with and without a tap running.

The DHW pressure is maintained by the mains pressure. The expansion vessel takes up the expansion as the hot water heats up and then replaces the volume back into the DHW cylinder as the water cools down. This function will stabilise the water pressure as the water heats and cools.

The expansion vessel does have a bladder and these do rupture eventually. when this happens there is no space for expansion so the pressure in the DHW system will rise as the water heats up. (assuming the non-return valve separating the DHW from the mains water doesn't leak back) If the bladder is burst then as the pressure rises the over pressure valve will leak to relieve the excess pressure. Leaking of the over pressure valve (pressure relief valve) is the usual symptom of a failed bladder.

If the bladder has failed the effect seen at the tap is that when a tap is opened a very short high pressure squirt will occur then the normal flow will resume. (The tap relieves the pressure difference from the over pressure relief valve pressure down to mains pressure).

Failure of the bladder will not cause the symptoms experienced by Rex

First thing to do is verify that the mains supply is providing the flow/ pressure you are expecting. Standing pressure may well be what you expect, but the flow rate may be such that pressure soon drops when you start using water.
Reducing mains pressure is an easy way for a water company to reduce waste through leakage and/or reduce overall consumption.

Posted By: ArtiglioFirst thing to do is verify that the mains supply is providing the flow/ pressure you are expecting. Standing pressure may well be what you expect, but the flow rate may be such that pressure soon drops when you start using water.
Reducing mains pressure is an easy way for a water company to reduce waste through leakage and/or reduce overall consumption.

Rex is complaining about much reduced flow on DHW taps after initial opening. No report of the same issue on the cold water water taps therefore I would assume that the flow rate and pressure into the property and up to the water softener is OK. If the water flow is teed after the water softener then I would assume the water softener is also OK. If the hot and cold water has separate paths through the water softener then the softener is also suspect along with the rest of the DHW system.

Posted By: fostertom

Posted By: Peter_in_HungaryFailure of the bladder will not cause the symptoms experienced by Rex

Having just had my HoLEP, I can assure Rex that it does get better.

Posted By: RexDon't think I can use HoLEP on the DHW but am seriously considering having a Rezum treatment myself in the near future.

What fun..................enjoy!!

Getting old sucks