Pumped shower now won't supply hot under any circumstances

[joefuller]

Hi everyone.

We had a brand new pumped shower installed over the bath 2 months ago as part of a refurb and, in the last week the HW has failed totally. At first we could get hot by cracking open a cold tap either on the sink or bath taps and then we were told it was because the CW pressure was too high so we dropped that at the mains and then had to resort to bits of tape on the taps (shower thermostat, supply/changeover and bath CW) showing where the 'sweet spot' was with the settings that allowed the shower pump to kick in and the HW to come through.

Now even that has failed and we can't get the pump to kick in at all so no HW through either the rain head or handset and no sweet spot with the controls, just a bitter taste!

We have a gas system boiler supplying a HW cylinder in the airing cupboard next to the bathroom. Yes, I know that's the same level but it supplies HW to the bath and all the basin taps on that floor just fine and until recently, the shower head and handset too. When they first fitted the bathroom, the HW came out of the rain head and handset at a dribble so they advised we buy a pump for the HW side from the cylinder and they fitted a Stuart Turner positive head regenerative showermate 2 bar twin shower pump. It worked, to a fashion for a while and now doesn't. The power supply and fuse to the pump are fine.

Please could anyone suggest how this can be fixed? Thanks

 

[CountryFan]

No ideas currently but surely at 2 months old it's under warranty? How did you reduce the pressure at the cold main?

 

[joefuller]

Cold main, just by turning the main inlet valve down a bit. There's one inside the house otherwise I could have done the same at the meter.

Yes, the pump will be under warranty but given it's never really worked properly without having to fiddle with the controls and crack open other taps I'm wondering if the problem is the system design rather than the parts.

 

[CountryFan]

Cold main, just by turning the main inlet valve down a bit.

That doesn't restrict the pressure only the flow. Try opening it back up a bit. Also, just re-read your OP and if it's a twin shower pump then the hot and cold should be balanced afaik.

 

[CountryFan]

Yes, the pump will be under warranty but given it's never really worked properly without having to fiddle with the controls and crack open other taps I'm wondering if the problem is the system design rather than the parts.

If it's never worked properly then you should call the installer back.

 

[joefuller]

Yep, I want them to put this right but I think they're out of ideas themselves after he suggested opening the cold tap to get the pump to kick in.

 

[CountryFan]

Well I hope you haven't paid them? Maybe contact Stuart Turner, they've been going some time and their technical department should be able to assist you, as in a forum unless you're able to take pressure measurements, not much we could offer in terms of support. Although, those familiar with shower pumps maybe able to offer some guidance.

 

[joefuller]

Good call about calling Turners, thanks! I did pay after it started to work and I don't like not paying tradesmen as I would want to be paid if I'd finished a job. Problem is if something then fails. Maybe clients should keep 15% of a job back for 12 months just in case lol! Not sure the trades would like that...

 

[Johntheo5]

A bit confused re your pump, is it a "twin" that pumps both hot & cold water?, the hot from the HW cylinder (fed from the CWSC) and the cold from the CWSC, these have a small pressure vessel on top to start the pump, a flow switch then keeps the pump running until you shut off both hot & cold. OR have you just got a "single ended" pump that just pumps the HW??.

 

[joefuller]

Not sure to be honest but this is the pump we purchased:

https://www.screwfix.com/p/stuart-turner-showermate-standard-regenerative-single-shower-pump-2-0bar/532pg

 

[Madrab]

1st problem - The shower should ideally be on a balanced supply - usually by pumping both hot and cold supplies, trying to pump one side of a thermo shower with the other on the mains can be fraught with issues, as you are now finding.

2nd problem - unfortunately you have employed workers that don't seem to know what they're doing.

You have an imbalanced supply and there isn't enough HW water flow to trigger the pump, given there is only a dribble of HW. That may be because the gravity HW just doesn't have enough head of pressure to activate the switch or the Cold Water mains pressure is stopping the HW flow. That and it sounds like they have also installed a shower designed for mains pressure and not gravity supplied HW. Try turning off the shower at it's power supply, turn on the shower and then turn the pump back on and see if it stays running that way.

The issue may be resolved by changing the pump to a universal (negative) head pump as that activates in a different way but even then there may still be issue with the unbalanced supplies.

Ultimately though it's down to the installers to fix IMO as this is definitely a design/implementation issue.

 

[HERTS P&D]

Post pictures of the pump, is it a negative head?

Andy

 

[Johntheo5]

Not sure to be honest but this is the pump we purchased:

https://www.screwfix.com/p/stuart-turner-showermate-standard-regenerative-single-shower-pump-2-0bar/532pg

You have a positive head pump which means that it requires a flowrate of ~ 1.5/2 LPM to get it to start, if the shower is in the bathroom, its unlikely to have enough head from the CWSC to give that flowrate, you could try two things, if only as a temporary measure, turn the shower temp control to fully hot and see if it now starts, if not, place the shower head on the ground to see if it now starts, then adjust the temperature control, might work. As stated above, looks like you need a negative head pump.

How much higher approximately, is the CWSC water level above the shower head?.

If there is a reasonable flow when turned to fully hot (but not starting), measure this into a known container and take the time in seconds to fill the container.

 

[HERTS P&D]

Take the shower hose and lay it down on the bath/shower and see if the pump comes on when turned on.

Andy

 

[joefuller]

Thanks all for replies. To answer some questions:

from John:
How much higher approximately, is the CWSC water level above the shower head? The CW cistern is in the loft just above the shower and on a frame, so perhaps 2-3 feet.

If there is a reasonable flow when turned to fully hot (but not starting), measure this into a known container and take the time in seconds to fill the container. Will do this when home but there is no flow of HW from the shower as the pump doesn't kick in. From the bath HW tap there is an OK flow even though it is on the same floor as the HW tank, not as much flow as the CW though obviously which is quite powerful and was more before we turned down the main tap.

from Andy:
Take the shower hose and lay it down on the bath/shower and see if the pump comes on when turned on. Yep, we did this just after installation when this first appeared and it did help it to kick in. Now though, no combination of laying the handset on the bath bottom, adjusting the shower temperature and handset/rain head tap has any effect.

from Madrab:
Try turning off the shower at it's power supply, turn on the shower and then turn the pump back on and see if it stays running that way. Yep, will try that when home. I had wondered a few weeks ago if they had wrongly advised a positive head pump. I might show him this thread! He has been good at engaging and coming back for snagging.