Low pressure Thermostatic mixer

[Joseph@FPM]

Hi, I am fitting a new shower and can anyone tell me if a low-pressure mixer bar would be ok feed from an electric hot water tank?

 

[Madrab]

Depends on how high the cold water cistern feeding the cylinder is from where the shower head will be and how low a pressure the shower can run properly at and what kind of flow it will supply at min pressure. Can't see it being that good TBH unless the cistern is say 5m+ above the shower head.

 

[Joseph@FPM]

Hi Mad, Thanks for the reply. The cold water supply to the bathroom is from the mains and the hot from the electric tank. same level as the bathroom with the feeder tank around 4mtrs above. I am not concerned overly with the pressure just as long as the bar will function properly?

 

[Madrab]

2 potential concerns -

1. the cold mains pressure may interfere with the lower pressure gravity fed hot water and stop or reduce the hot water flow, if the difference is significant - if it does, you'll need to pressure balance the supplies
2. the bar shower may need a minimum pressure to allow it to work properly, even if it's classed as a low pressure item - that should be specified in the MI

 

[Joseph@FPM]

Hi Rob, would a pressure reduction valve on the cold water feed solve my problem IYA?

 

[Madrab]

Do a bit of checking first and only look at that if there's an issue. What bar mixer is it, do you know the spec?

If the base of the Cold Water Storage Cistern (CWSC) is 4m above the level of where the shower head will be then you may be ok as that'll supply up to .4bar to the hot supply, pipe runs dependent. It'll come down to the difference between the mains pressure and the pressure of the hot feed.

Whatever the result, if there's an issue there will be a way to sort it out.