Pump hunting or running on

[waccoe]

Hi all, I'm turning to you guys in desperation. Plumbing isn't really my thing, but I'll try and explain this as best I can. We have a standard gravity fed system, but the whole house operates off a Stuart turner monsoon shower pump. We did have a negative head pump, installed in the airing cupboard, but it was starting to come on randomly and keep running.

We had a plumber round, who said that the pcb had gone on the pump and recommended replacing it, the pump was about 6 years old. Anyway, we've replaced it with another Stuart turner but this time a positive head 3 bar pump, but it hasn't helped. The pump will now randomly hunt for extended periods, pulsing on and off, usually after an upstairs bath is run, the only way to stop the pulsing is to turn the pump on and off again, or run another tap upstairs. If it's not pulsing it will randomly come on and stay on for long periods, 5-10 minutes, again, can be fixed by running a tap, or power cycling the pump.

The plumber is refusing to help, he says it must be a faulty appliance or a leak, but I can't find any leaks whatsoever. The only thing I have noticed that the overflow from one of the tanks in the loft seems to be leaking too.

Would anyone have any ideas what could be wrong? Or where to start looking? Alternatively if anyone could recommend a decent plumber in the camberley area, who's not going to rip me off and might take responsibility for his work.

Any help gratefully received.

 

[Youllneverguess]

The pump is probably pushing water through a faulty mixer tap or shower.

 

[waccoe]

Thanks, but does that mean that the tap/mixer should be leaking while the pump is running? I can't seem to find any leaks anywhere.

Been on going for months this, finally driving me bokers

 

[Youllneverguess]

Not necessarily. Shower mixers blend the water BEFORE the on/off valve. If there are no/faulty non return valves in the shower mixer(s), the pump could be pushing through.

 

[ChrisOxford]

The only thing I have noticed that the overflow from one of the tanks in the loft seems to be leaking too.

Does the pump start up when this tank tries to re-fill (i.e. if you try pushing the float valve's float downwards into the water)? If so, then maybe a faulty float valve is the cause of all your woes.

P.S. Float valve = ball valve = ball cock.

 

[waccoe]

The only thing I have noticed that the overflow from one of the tanks in the loft seems to be leaking too.

Does the pump start up when this tank tries to re-fill (i.e. if you try pushing the float valve's float downwards into the water)? If so, then maybe a faulty float valve is the cause of all your woes.

P.S. Float valve = ball valve = ball cock.

Thanks, just had a chance to check the loft tank, pump isn't running when the tank refills. Strange thing now, is that if I run any tap upstairs for just a split second, the pump will kick in, and now just keeps running for minutes afterwards. Poer cycling it, seems to sort it out. Anyone any other ideas?

 

[waccoe]

Just thought I'd post a couple of other strange things. In an attempt to find where the water was going, I left the pump running when it was running on, and noticed that after a few minutes, both the cold inlet to the pump and the cold outlet out of the pump were both very hot to the touch, as though they had hot water, running through them.

Does this indicate anything that might help narrow down what's going on?

 

[joe-90]

You need a non-return valve in the shower feed. The cold water under mains pressure is pushing the hot water back up the way it came. Mixer showers don't actually have an 'off' position, that is why they must be fed from a balanced pressure supply.

 

[waccoe]

Thanks joe-90. Could the lack of a non return valve also cause the pump to kick in and produce the random things I've been seeing?

The pump powers a steam shower, when we had it fitted, the supplier said we should fit a negative head pump, we've replaced that negative head pump with a positive, as the plumber said we didn't need a negative head. The pump's in the airing cupboard.

Anyway, am I right in assuming that a non return valve isn't needed on a negative head pump?

 

[Youllneverguess]

The non return valves are needed on your shower. As per my posts several days ago.

 

[waccoe]

Thanks for the help guys..... as I said, I'm very much a plumbing novice, I just didn't realise that's what you meant "youllneverguess". I'll investigate the non return.

 

[Youllneverguess]

Happy hunting...