Pulsing Thermostatic Concealed Low Pressure Mixer Shower Drainage and wastage systems and plumbing help, advice and answers

[Paulq13]

Hi, have installed concealed thermostatic low pressure mixer valve with 8" square shower head in upstairs bathroom both hot and cold are 15mm copper and were diverted from old bath, problem is when i turn shower on it takes about 10 second for water to come out the riser, then it pulses every 1-2 sucks with weak pressure to shower, if i tilt shower head back it only produces water from bottom half of head.

System is cold mains feed and hot tank fed with cold water storage in loft.

Any help for frustrated diyer

[stoneyboy]

Hi paulq13,
Assuming you have fitted an extra low pressure shower valve - these should specify a pressure below 0.3 bar. You need to instal a shower pump - ideally you will need to take hot and cold supplies from your tank fed system.
Regards.
Stoneyboy.

[Paulq13]

Hi Stoneboy, firstly thank you for the reply,
The thermostat shower valve state for pressure from 0.1 bar, i am on positive pressure, but only just.
I think there is also a large pressure inbalance between hot and cold so you are right i should have had dedicated hot and cold feed, am going to tap cold from storage tank and new hot from cystern and run through pump, unfortunately though will have to strip tiles and Marine please from front of shower to re plumb, should have done my research better, again thank you for the reply