Shower Pumps - Regenerative V Centrifugal

[CedGTV]

I've done a search on line and on here but am confused as to these two alternatives.

I'm only after replacing my loft based 1.3 Bar unit, supplying a single shower & it's a on it's way out pump, but wondered what was the difference between the two.

Thank You

Ced

[CedGTV]

Sorry - Just to add info

2 input, 2 output, Cold & Hot, 22mm connections if that makes much difference.

Thanks

Edited by CedGTV on Saturday 24th September 17:06

[jagnet]

Centrifugal pumps are fractionally quieter than regenerative, but to be honest, in a domestic installation there's really little difference.

Regenerative pumps are slightly less prone to damage by cavitation and dry running, though neither respond at all well to air in the system.

You mention that your pump is installed in your loft. Is the cold water tank raised up at all? The reason I mention this is that most domestic pumps need a minimum flooded suction head - Salamander requires a minimum 600mm from the top of the pump to the bottom of the tank, Stuart Turner requires 500mm. Less than this can cause problems with water starvation to the pump, causing undue wear.

I've come across several installations where the base of the cold tank and the pump are level, and whilst it seemingly worked fine initially, it wasn't long before the pump started malfunctioning. In one case, this took less than a year to appear.

[CedGTV]

The tank is about 200mm above the pump.

Thought it was sounding laboured when I was in the loft the other day.

One thing after the other at the mo.

Internal Stopcock is solid and won't turn a bit and I fear breaking it, so off into the drive way to find the stopcock and that's the old 3/4 square type. So off to Screwfix to find that key now.

The tank's ball valve is all furred up and causing the tank to over flow hence the trip to the loft.

Busy plumbing day ahead and I had a tee time booked as well for this afternoon.