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Negative Head Pump
stevebubs - 1/5/08 at 05:58 PM

Another Plumbing question folloring on from my previous post on the subject..

Could I install a negative head pump under the bath to boost pressure?

If so, any recommendations on make/model?


JohnN - 1/5/08 at 06:56 PM

I haven't read all your original post, but, why not link the cold tap direct to mains pressure and make the hot tap 22mm pipework?

As for the pump question, sounds like the power shower scenario. Problem is, that with low suction pressure the pump will generate negative suction at higher flows, cavitate and destroy itself quicker than average.

Answer could be to locate the pump at a point where it can be adequately supplied

[Edited on 1/5/08 by JohnN]


stevebubs - 1/5/08 at 08:36 PM

quote:
Originally posted by JohnN
make the hot tap 22mm pipework?



It already is 22mm pipework...with the exception of the last 12 inches...

[Edited on 1/5/08 by stevebubs]


stevebubs - 1/5/08 at 08:38 PM

quote:
Originally posted by JohnN
As for the pump question, sounds like the power shower scenario. Problem is, that with low suction pressure the pump will generate negative suction at higher flows, cavitate and destroy itself quicker than average.



I thought negative head pumps were designed to beat this....


stevebubs - 3/5/08 at 12:03 PM

Been and traced all the plumbing.

Bathroom has own dedicated 22mm hot feed from the tank and the cold feed also runs through the airing cupboard - cold water tank is located directly above it.

Both feeds then go under the floor to the bathroom.

Going to splice a Salamander CT75 into the pipes into the airing cupboard tomorrow...

[Edited on 3/5/08 by stevebubs]


stevebubs - 4/5/08 at 05:37 PM

CT75 solved the problem....nice pressure in the bathroom now...