problem with bath shower mixer

[chugginton]

hi can anyone please advise,i am tying to fit a new thermostatic bath shower mixer,old one was just a manual mixer but has got really hard to operate.House has combi boiler,22mm pipework to bath.cold water pressure seems high.Problem is that have tried to fit two thermostatic mixers and both will not turn supply off totally.second was a Hansgrohe Versobsm which stated would fit any system.Have checked shut off valve inside main body all seems fine.Does it need PRV on mains or pipework changing.Or perhaps you could recommend a decent manual mixer insted.I have also tried turning mains stopcock right down but still no good.thanks.

 

[Plumbstar Tom]

it probably is suitable for all systems but needs balanced pressures and a maxium of probs 5 bar pressure as well

check what the instructions say

many of the manual 'branded' bath shower mixers will be fine. just dont go and get one from one of the sheds tho

 

[chugginton]

thanks,manual states ok upto 10bar,but on combi install shows 15mm pipework to shower if using as wall mounted but does not state pipework size for use as bath shower mixer i assume this has to be 22mm or should it be only the last .05-1m that is 22mm.How do i balance hot and cold pressures.You can probably tell by now plumbing not my trade,carpenter,builder doing what i thought was a quick job for family.(should know better).thanks again

 

[emerald]

i would go for a PRV on the incoming mains, as turning back the main stop tap will only reduce the volume, not the pressure