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anna71 · Joined: 02 Apr 2008 Posts: 3 Location: haddenham, uk

Hi,
We just had our en-suit done, looks great but...we have the issue with the shower and our plumber doesn't know what else to do.
We do have cold water tank in the loft. New shower is hudson reeds Minimalist Grand Rigid Riser. Pump instaled is monsoon 2 bar twin, new and instaled 1 month ago. Shower does require minimum 0.1 bar pressure to operate. the distance between the top of the shower head(fixed) and the water tank is about 0.9 m. And here is the issue. When we do switch the shower there is no water comming. We also have the flexible head. If we lower that to the try (distance more then 2m between the water tank and the head) water will come. Producer is saying that we need negative pump. I will agree if we will use the fixed head, however flexible one needs to go far to low to back up the story with to low cold water pressure. And now is the twist. Last week the shower was working perfect. Stright on with no trouble. And now we are again back to not working shower. Confused

We do have another shower fed from the same pump, on the same level (old shower) warks great, no problems....
One more thing, sometimes when we do switch the hot water tap off anywhere in the house, pump will switch itself on. I know it is because of the air being traped....
Producer of the shower tells us to remove no return valves from the shower valves, but it will be done on our own risk. We do not know if we should do it.
PLEASE HELP! Why the shower did work so great for a week and now stoped? Is the problem with the air? How can we fix it, as I am nbot sure that the negative head pump is the answer, not now when I did see this shower work fine fore more then a week.
Thanks
Thank

thescruff · Moderator Joined: 03 May 2003 Posts: 4164 Location: Bath

If you are collecting air then something has been connected wrong.

The pump running when you close another tap is shock waves not air.

You need to understand that for the flow switch in the pump to switch it on there has to be a flow, by lowering the hand set you are increasing the head and therefore the flow needed.

An negative head pump, which you need, works on pressure, as soon as you open an outlet the pressure drops and brings the pump on.

anna71 · Joined: 02 Apr 2008 Posts: 3 Location: haddenham, uk

Thank you for that. How can I make sure that there is no shock wave when I turn off the hot water tap? And why it is not happening all the time?
I know that by the lowering my flexible head I do increase the presure but if only 0.1 bar is required I will not need to put the head so low (more then 2m from the tank), and it does not work if it is any higher. Also it can you explain why it did work beautifly for more then a week?
Is removing the non return valves dangerus?
Thanks

thescruff · Moderator Joined: 03 May 2003 Posts: 4164 Location: Bath

What you have is a reed switch in the water pipe any movement and it will bring the pump on, quarter turn taps shut the water off very quickly, and will cause all sorts of ripples downstream, yes you can fit shock arrestors which may help, but personally Not worth the small expense.

You are are below the minimum pressure for starters, and the conditions have to be perfect for it too work, pipe sizes, number of fittings all = resistance and pow, it don't work

Removing the check valve, if you were within the minimum head, would probably do the job, it would also break water regulations and put you at risk of flooding the storage tank with back flow.

There should be a filter in the valve which may be worth checking to see it any bits are restricting the flow.

I think you either have to raise the tank, best part of a 1m or my plan would be change the pump and do away with the hassle