Fitting A Shower Pump To One Side Of A Thermostatic Mixer Shower.

[j0nb0y]

I am looking at fitting a shower booster to the hot water side of my thermostatic mixer shower. The cold side is mains pressure. The shower head is in a 'positive head' position, so I Was going to fit a positive head pump, but have been advised because it is going against mains pressure going into the mixer shower, I need to install a universal or negative head pump. ( which are all two or three times the price).
I am looking for advice as to whether a positive head pump would actually work. If anyone has any experience with these pumps.
Any advice, much appreciated.

[The Builder]

If you're sure you have measured, and are satisfied you have sufficient head, Then a positive pump is all you need Jonboy.
I don't see the problem of the cold supply being at mains pressure.
That's why you're fitting a pump in the first place.

see here..............

https://www.anchorpumps.com/blog/positive-negative-shower-pumps-explained/

[j0nb0y]

Cheers 'the builder', that is my thoughts exactly, but technical departments at both Salamander and Stuart Turner tried to advise the much more expensive 'negative head' pumps. Think they are told to advise the more profitable models. Technical at Grundfoss said a 'positive head' would be fine. I have done flow rate tests and pressure tests and both are compatible with positive head pumps.