No.1 U.K. Professional Trade Forum, Plumbing, Gas, Electric, Tiling and Joinery Forum

I have a mixer/tap type shower in the bath. It's in a bungalow. Hot water tank. The water pressure isn't brilliant but above the minimum.

The shower wasn't up to much so asked a plumber to install a pump to improve things. It works fine when hot, but reducing the hot for a more tepid shower the flow reduces and the pump starts doing this. See the 12 second YouTube video.

I need to get them back, but any thoughts about the installation?

https://youtube.com/shorts/4hDhWljQk4A?feature=share

doesnt look right to me. should have no 90deg elbows and sounds like its trying to pull air!. is the mains tank adequate size to keep up with the flow?

My eyes might deceive but I don't see cold water connection to pump.
Just two flexi unattached.
With impeller both ends, running one end dry will result in bearing failure.
A dedicated cold water feed should go to pump, in 22 mm, from the same cold water tank in loft that feeds the DHW cylinder

Removed. Should gave been a reply.

REDSAW wrote: ↑

February 24th, 2024, 9:35 pm

doesnt look right to me. should have no 90deg elbows and sounds like its trying to pull air!. is the mains tank adequate size to keep up with the flow?

Thanks. I've checked the tank in the attic. Its big and was only down an inch or two after 10 minutes running. So I think capacity there is fine.

joni os wrote: ↑

March 1st, 2024, 1:59 am

My eyes might deceive but I don't see cold water connection to pump.
Just two flexi unattached.
With impeller both ends, running one end dry will result in bearing failure.
A dedicated cold water feed should go to pump, in 22 mm, from the same cold water tank in loft that feeds the DHW cylinder

Your eyes do not deceive you and I did wonder about that, I thought it seemed 'unblanced'. I think the connectors on the pump are only 15mm, would 22mm be essential on the cold?

Volume of water out of pump can be no more than volume of water entering pump, albeit at a higher pressure, so 22 mm prior to 15 mm flexi is normal manufacturer's spec.
If cold water feed is short and uncomplicated 15 mm may be adequate for a 43 degree shower. (Hot water at 63, cold at 13. ratio hot to cold is 3 : 2) but a temperature control at shower, less limited by availability, is desirable. Flexi at pump essential to accommodate vibration of pump. Pump will suck water through a short flexi, just as we can suck water from a glass with a 8" straw, if straw was 8 foot long effort would be greater.

Gruff wrote: ↑

February 24th, 2024, 2:34 pm

I have a mixer/tap type shower in the bath. It's in a bungalow. Hot water tank. The water pressure isn't brilliant but above the minimum.

The shower wasn't up to much so asked a plumber to install a pump to improve things. It works fine when hot, but reducing the hot for a more tepid shower the flow reduces and the pump starts doing this. See the 12 second YouTube video.

I need to get them back, but any thoughts about the installation?

https://youtube.com/shorts/4hDhWljQk4A?feature=share

hey I would maybe seek help from a professional if you arent sure If you do need a good shower pump I got a shower power booster pump the other day it's done wonders for my shower https://plumbhq.uk/products/shower-power-booster-pump

It's possible that the pump installed may be oversized for your system, causing it to cycle on and off excessively when there's a lower demand for hot water. This can lead to inefficient operation and potential damage to the pump over time.

Another possibility is that the balancing valve on the shower mixer isn't set correctly to balance the flow of hot and cold water. If the valve is set too far towards the cold side, it may restrict the flow of hot water and cause the pump to cycle as it tries to maintain the desired temperature.