thermostatic bathfiller/shower

[ostrich]

my elderly inlaws have a 2nd hand walkin bath,it came with HP bathfiller which needs min 1bar.The cw tank is in airing cupboard next to bath so not enough head to even work an LP thermo mixer!
Loft hatch is tiny so cannot put tank in attic and fit LP mixer!
I guess this means a shower pump will have to be fitted,but cw tank is small 14"Wx24"dx24"h(20 galls??) so is there a risk of a twin impellor
pump (1.5-2bar)draining the cw tank??
If so could i use single pump to hot side of mixer,and use existing cold mains through pressure reducing valve(set to say 1.5 bar)to cold side Would this work

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[Softus]

my elderly inlaws have a 2nd hand walkin bath,it came with HP bathfiller which needs min 1bar.The cw tank is in airing cupboard next to bath so not enough head to even work an LP thermo mixer!
Loft hatch is tiny so cannot put tank in attic and fit LP mixer!

Why not install a low pressure mixer anyway?

I guess this means a shower pump will have to be fitted,but cw tank is small 14"Wx24"dx24"h(20 galls??) so is there a risk of a twin impellor
pump (1.5-2bar)draining the cw tank?

Yes.

If so could i use single pump to hot side of mixer,and use existing cold mains through pressure reducing valve(set to say 1.5 bar)to cold side Would this work

Yes. But you might need a 'negative head' pump, so instead of going to that expense you might as well replace the taps.

 

[ostrich]

thanks for reply softus,problem is LPmixer needs to be thermstatic to avoid scalding(with care bath you have to sit in while filling,and cant get out until drained!)Minimium head required for thermo LP mixer is 0.2 bar they have
more like 0.05bar to tap and negative head if they were to use shower diverter(they could use thier electric shower to avoid this)