i have recently had a salamander ct50 1.5 bar twin pump positive head fitted to a therostatic shower from day 1 the shower started pulsing i have had the plummer back a few times he has fitted air lock caps and tried to change pipes around but no luck the shower works fine on full heat and full cold but when you have it to a comfortable temp it will start pulsing any ideas? or a reliable plummer to fix in the liverpool area many thanks