Another shower pump problem, or problems :)

[Robert Tyrrell]

I have two customers that I've fitted shower pumps for and both are having problems but I cannot, for the life of me, get to the bottom of the problem with either so I'm looking for some advice.

Customer 1:
They fitted a new bathroom and asked me to fit pipework to sanitary ware etc, as well as install a shower pump to create supply for two showers. One shower is in the en-suite, the other side of the wall to the main bathroom where the pump is installed underneath the bath, and the second shower is downstairs, below the main bathroom. There is a separate cold water supply from the CWSC in the loft to the pump.
The problem is that that the pump starts ok when they turn on the shower but then the hot water stops and the pump is making a stuttering noise until it is turned off and then on again and it's a repeating loop of this.
I have fitted the pump with an 'S' flange, as recommended by the manufacturer (Stuart Turner), and as seen in the photo attached. Stuart Turner say that it's water starvation but i can't see it being that really. If you guys have any ideas I' like to hear them - good ones though


Customer number 2:
Similar setup but with a single impeller pump on the hot water. This is in the airing cupboard adjacent to the en-suite bathroom where the shower resides. He can only get the pump to kick in if he drops the shower head to the floor and then lifts it again. 'S' flange fitted, dedicated pipework for hot. Mains cold supply pressure regulated via a PRV in the loft.
No photos of this one.
Again, any decent ideas would be appreciated

 

[Plumbstar Tom]

Customer 1: The pump should be cited in the airing cupboard and not under the bath. It does sound like a restriction or blockage on the HW side. but the install looks good, an Essex flange is an even better solution IMHO. Check the filters too. both at the pump and shower. Try swapping the pump supplies over (i.e. cold side to hot side)

Customer 2:
I suspect this is due to the showered no being far enough flow the CWSC to activate the flow switches, the MI's will tell you what the distance is but note that they do not take pipework with restrictions and multiple bends in it. Solutions are to increase the CWSC height, reduce the complexity of pipework, fit a Negative head pump.

 

[JCplumb]

How big is the cwst? How's the hot flow from an unpumped point in the upstairs bathroom? But most importantly, why are there so many switches on the right hand side of that cylinder?

 

[deg]

In the picture you posted, where is the hot supply for other outlets. Is that a stopend fitted below the vent?

 

[Chalked]

Custard 1
Looks like that's the hot for the whole house, as I can only see a vent going from the cyl. If anyone opens a tap the pump will draw air in.
The flange should be for the shower pump only.
Solution would be. Make pump a dedicated supply and check for blockage on cyl cold feed.
Custard 2
Looks like the cold mains pressure is crosding through to the hot supply. So the pump won't detect any flow. It's never good yo have pumped and mains to a mixer, but your probably stuck, due to location.
The only solution I can see, is to swap for a good negative head pump.

 

[PlumbBobBob]

could be the angle but the hot looks like it is going up from the flange

 

[Robert Tyrrell]

I didn't do the electrics. The customer did all that, and a lot of it relates to stuff outside of the bathroom I think.

 

[Robert Tyrrell]

It's the angle, definitely going down. I've had the level on it to make sure.

 

[Robert Tyrrell]

Customer 1: This is a pump that feeds the whole house, but only for the hot water side. The main bathroom. and en-suite are supplied on the cold water side of the pump from the cwsc in the loft but everything else in the house in one the mains for cold water.
They don't have a problem with the hot tap in the kitchen either, it appears to be just the showers causing a problem.

Customer 2: Can't see how this is happening as it's a single impeller pump for the hot only, and both the hot and cold have been matched for pressure suing prv's.

 

[Robert Tyrrell]

Hot supply for the whole house and yes, its a stop end that's on a redundant pipe that I can't get to, just in case

 

[Robert Tyrrell]

Customer 1:cant get the pump in the airing cupboard. I'll try swapping the feeds - if I can ever get back in as they're always out working.

Customer 2: The CWSC is around 2.5 metres above the pump and there is plenty of flow. The CWS drops straight to the cylinder and it's a 50 gallon cistern as well.