Shower pump problem

[Steve p]

Hi, I hope someone might be able to advise on my shower pump which seems to be intermittently not working. In particular it is making high pitched noises sometimes and then more recently the hot water has stopped being pumped so there is little more than a dribble coming through.

I suspect there is air in the system but I've tried bleeding it by turning off the electrics and running the shower for a few minutes. This hasn't worked. I think the fault is only with the hot water feed, the cold is running fine

From what I've read, the first installation of a shower pump was not ideal - it is above the hot water tank and takes water directly from the top pipe of the tank. However I can't solve that issue now so I'm looking for ideas on how to get the pump running properly again. The newest pump was only put in 14 months ago.

I've attached a couple of photos:
- One is a crude picture of the set up, the pump is in the eaves of the loft, the header tank in the apex of the roof and the HW tank and shower are upstairs.
- the second is the shower pump itself

Any suggestions are more than welcome!

 

[stem]

One of the problems with a hot water cylinder is that air bubbles collect at the top when the water is heated. If this air gets into a shower pump it causes all sorts of problems. So the water should be taken from a point where there isn't any air. From your description I suspect that this may be your problem.

The two bottles above the pump are automatic air vents, but small air bubbles alone aren't generally sufficient to operate the integral float to allow their release so would likely still get drawn into the pump.

Special flanges are produced for this purpose [Essex and Surrey Flanges] I can't tell from your sketch if you have one or not.

Shower Flange

• stem
• 18 Aug 2009
• 3

Alternatively the pipe connection should be such that the air is allowed to vent, and the water for the shower taken off elsewhere where air doesn't collect. In this case the connection to the hot supply is made much lower down than the vent.

Untitled

• stem
• 1 Feb 2011
• 5

Here an angled outlet from the cylinder ensures the air rises up the pipe and the shower takes its supply from the bottom

Untitled

• stem
• 1 Feb 2011
• 1

The location of the pump isn't ideal but it may be OK, some are designed to work even with a negative head. You would have to check the instructions.

 

[Steve p]

Thanks, that all makes sense. I'm almost certain the issue will be a steady accumulation of bubbles in the pump that are not being released by the automatic vents.

I have attached a photo of the top of the tank. There doesn't seem to be evidence of the type of flange you describe. Looks like simple pipe work to me.

 

[stem]

I can't tell if the vertical or horizontal branch are feeding the shower, but in either instance it's still a poor installation.

 

[Steve p]

The vertical branch heads up into the loft. It then turns horizontal and after that there is a T junction. One feeds the shower pump and I guess the other one goes up towards the header tank or overflow.

I had a look at the inlet pipe to the pump, there was some gunk in the filter which I've now cleared but it hasn't resolved the issue. The plumber who replaced the pump last year thinks there might be a problem at the shower end. I think it's the pump now but the shower unit is my last chance. Unfortunately getting the unit out is a major effort because it's set in the wall which I can't bring myself to do right now.