Water Pump

[bogit&scarper]

I fitted a power shower some 3 years ago with a separate pump. The out put goes to the shower only. When we use the cold water(only) in the bath or sink the pump tries to switch itself on but in surges. At times it freezes completely as if the motor is going to seize up. It works perfectly well when shower is on..
I belive this is because the water is receding from the pump when we use other appliances (although it does not happen on the hot).
Can any one suggest a solution that does not involve re positioning the pump (in a difficult position with pipes under bath floor).

 

[Softus]

Either:

1. Refer to the manufacturer's instructions - you'll probably find that non-return valves are recommended.

2. Switch off the pump when the shower is not in use. You could fit a pull cord switch in the bathroom for this, or an isolating switch on the wall outside the bathroom, near the ceiling.

 

[breezer]

a thought.

what about seeing if it has an adjustable pressure switch and if so adjust it

 

[Softus]

A thought.

I'm baffled by that breezer - what do you mean by an adjustable switch? And an adjustable pressure switch?

 

[breezer]

my thinking is to adjust it (pressure switch) so it doesn't notice the pressure drop when other taps opened, but when shower tap opend it does

 

[Softus]

OK - I bow to your greater knowledge on this one - must do some research...

 

[breezer]

dont bow, grovel!

seriously it was only a thought, it may not be feasable, i am not a plumber or heating engineer

 

[bogit&scarper]

Thanks guys, am going to try the non return valve as thats the easiest to do. The switch is next on the list although this is going to be difficult to re route the wire to switch due to location of power supply. WIll let you know what happens. Can't see any way of adjusting the strengh of the pump (3 bar).

 

[bab]

twin impeller shower pumps dont have presure switch,s they hav a magnetic flow switch that when gravity flow pass's through the pump to the valve it line's up with the magnetic micro switch that powers the pump. thats why the pump should have a dedicated hot & clod water supply. when you run other fittings that also feed the pump the suction & back pressure move the finely ballanced flow switch. & non return valve may greatly reduce the low pressure supply to the pump & even stop it if it a double check type is used. isolating the electric is more garanteed if possible . the pump should have an isolater that isn't under the bath with a 5 amp fuse .

 

[bogit&scarper]

Fitted non return valve to cold water feed to pump. Convinced this was going to work but it didnt in fact made no difference.
Its got be baffelled. Why would pump want to try and work when taps in bath and sink are not linked to pump at all. And now with non return valve the pump should not even know those taps are on.

 

[Softus]

Fitted non return valve to cold water feed to pump. Convinced this was going to work but it didnt in fact made no difference.
Its got be baffelled. Why would pump want to try and work when taps in bath and sink are not linked to pump at all. And now with non return valve the pump should not even know those taps are on.

Why didn't you fit a NRV on the hot supply to the pump?

 

[bogit&scarper]

Hi Softus,

Do you actaully think thats going to make a difference?. Its only that i cant see the pressure dropping from the hot supply if its only the cold that's causing the problem. Hot comes from the hot tank and cold from the header tank. If its going to make a difference i'll do it

 

[kevplumb]

if you have a twin impeller pump it has TWO switches

 

[bab]

somethings not quite right about this. if the cold to the shower is direct from the tank is it tee'd off the same cold from the tank that feeds the bath ,basin & toilet, if not thats spooky.If so thats why. & if u read my last post the back pressure after use will still pas the n r valve.

 

[Softus]

Hi Softus,

Do you actaully think thats going to make a difference?. Its only that i cant see the pressure dropping from the hot supply if its only the cold that's causing the problem. Hot comes from the hot tank and cold from the header tank. If its going to make a difference i'll do it

Apologies - you have a point. If turning on the cold causes the symptom, then please ignore my post.

However, bab has the best point of all - if your shower feeds are direct from the cold storage cistern, then how is even the cold tap having any effect at all? The logical answer is that it shouldn't, and this is consistent with the NRV making no difference.

What kind of taps are they that are causing the problem? Single lever monobloc by any chance? (That scratching noise is me clutching at a straw).