Shower problem, plumber advice required

[Compostella]

We have just recently had a new bathroom installed and are having problems with the shower.

The shower runns off a pump installed directly above the thank. It is the same pump (about 1 year old) as was there before and it worked fine.

When the bathroom was installed, the plumber had to fit another pump for the hot water to the basin taps and bath taps. This is installed off the same hot water pipe as the shower pump.

But, now when I switch the shower on it takes over 30 mins for the pump to kick in.

Anyone know what it could be? My theory is that the main pump is pulling water from the input side of the shower pump and that because that is installed above the tank, it takes time for the water to work its way up to the shower pump and trigger the flow switch.

If you start the shower within about 2 mins after its has been working its usually starts straight away

[tezestwing]

Hi compo to my mind you can't have 2 pumps needing the same water which pump has first call of hot water draw off ? you did not say, are the sink and bath hot and cold on pump?.
Also if the new pump to sink & bath is not on but the shower is on demand then that should be as it was before any modifications I would get the plumber back HTH Tez

[Compostella]

Its just the hot that is on pump with the basin/bath

On the shower it is both.

Both pumps have equal call as they are off the same feed.

The plumber has been back and he says that the only fault that there could be is the shower pump. He's not saying that its broken but that is the only thing left that it could be. Before I replace the pump I wanted to check it out on here.

[tezestwing]

I think your theory is correct, only when the new pump is on though, so what has changed since before the new bathroom HTH Tez

[markja]

two points.

1) was the shower changed? if the original one sealed when it was switched off no air could enter via the shower head and allow all the water to run back through the system and empty it. (put a drinking straw in a bowl of water, place your finger on one end and lift that end up out of the water, it stays full until you let air in and the water drops. ) note: it could be the new bathroom fittings that are letting the water run back.
2) if the pump is above the tank (immersion i assume ) is it below the static tank that is in the loft? the pump needs to be in a position that keeps it primed with water so it pumps water not air. it isn't very good at pumping air to draw water up.

[Compostella]

We've sussed it

The valve is faulty.

I disconnected the shower and opened the valve after the pump and the pump came on straight away

Its the valve, another on its way