Monsoon 3.0 Bar Twin Pump keeps running when no water demand

[FozzieBear]

I have a bungalow with vented hot water system. I have just had a new kitchen and wet-room installed and performance at modern taps was appalling so have fitted a monsoon twin impeller pump to provide whole house boosted water.
This works fine and has drastically improved flow at taps etc. However when flushing the toilet in the main bathroom although the cistern has filled and ball valve shuts off the pump still keeps running. I have proved this by open and closing a cold tap while the pump is still running and then the pump stops. I think its because the valve closes slowly as the cistern fills so the pump doesn't sense the flow stopping. Unfortunately I cannot get a separate cold water feed to the WC. I have spoken to Stuart Turner tech support and they cant really offer any solution other than possibly changing the float valve. Whats strange is the new WC in the wet-room which is on a Gerberit frame works fine and the previous 1.5bar pump never displayed these problems only the new 3.0 Bar pump. I think the valve in the cistern is a Torbeck with low pressure insert? Can anyone recommend a replacement valve that might shut quicker than the current type or any other suggestions.
Fozzie

 

[HERTS P&D]

See below:

https://www.screwfix.com/p/fluidmaster-bottom-entry-brass-shank-fill-valve/47792

https://www.screwfix.com/p/fluidmaster-side-entry-brass-shank-side-entry-fill-valve/49088

Andy

 

[FozzieBear]

Thanks Andy Ill take a look at these.

 

[Madrab]

You must have mains cold water to the sink, is that no where near the toilet?

I would always try to avoid pumping anything with a valve, like a toilet/WM/etc, just pump the taps and shower. It's just asking for issues never mind a pump going off at 3am when the toilet is used.

 

[FozzieBear]

You must have mains cold water to the sink, is that no where near the toilet?

Mains comes in at front of building and bathroom is at back. Bathroom has vaulted ceiling so cant get over the top. Even if I could WC is back to cabinet and would mean ripping out cabinets to run a new supply from anywhere even under plinths. There is an access panel in worktop so I can hopefully change ball valve.

would always try to avoid pumping anything with a valve, like a toilet/WM/etc, just pump the taps and shower. It's just asking for issues never mind a pump going off at 3am when the toilet is used.

Not ideal I know but ST do make pumps for whole house pressure boosting so shouldn't be insurmountable and as stated new Gerberit frame and cistern in wetroom don't cause same problem.The setup is really a temporary situation as saving up to have a megaflow installed.

As Herts P&D suggested ill change ball valve first.

 

[HERTS P&D]

You can always put a timer on the pump so that it only works from 6am to 11pm, that way if someone uses the toilet a t 2am it wont go off.

Andy

 

[FozzieBear]

Good Idea.
We have a houseful at moment as whole family (including grandchildren) self isolating with us and had to get up twice in the night to run the cold tap to stop the pump after boys used the toilet!!!!

 

[Madrab]

Not ideal I know but ST do make pumps for whole house pressure boosting

Oh I wasn't suggesting it can't be done, of course these can be used as whole house pumps, it's just in my experience that it can sometimes get convoluted and issues creep in when they are connected to mechanical/electrical valves, especially older ones or as the valves get older, as they sometimes have issues with the surge of pressure that these pumps can deliver, especially ST Monsoons.

So longer term connecting them to valves is best avoided, in my experience.

 

[FozzieBear]

OK so good news first. I took lid off the cistern whilst pump was still running and noticed it was slightly overflowing so valve was possibly never turning completely off. I have adjusted water level and pump now turns off after valve closes. However I can still here it dribbling so need to change it. Does anyone recognise this type of ball valve which appears to be specialist? Alternatively are there compatible replacements ie will Fluidmaster
suggested by Herts P&D still fit?
Fozzie

 

[picasso]

Looks a bit tight for a fluidmaster,

these are good as they can fit tight against the side of the cistern and still work properly

https://www.ebay.co.uk/itm/293305351263

 

[HERTS P&D]

See below:

https://www.ebay.co.uk/itm/290723739781

Andy

 

[HERTS P&D]

This is the same as yours but in brass, just make sure you turn the water off first:

Andy

 

[picasso]

Not sure why herts is recommending a slow close valve when its on a pumped supply, the fast close he recommended earlier ie fluidmaster ect are much better.

 

[FozzieBear]

See below:

https://www.ebay.co.uk/itm/290723739781

Andy

Fit a repair kit!! Good idea for a first off. Many thanks

 

[HERTS P&D]

Not sure why herts is recommending a slow close valve when its on a pumped supply, the fast close he recommended earlier ie fluidmaster ect are much better.

I added the video to show how to change the washer. (Easier for the OP to do on a concealed cistern.)

Andy