New on here, but hoping for some quick assistance. Has anyone plumbed in a kitchen mixer tap with spray head attachment. You know the type, singe hole stainless steel 11/2 bowl sink and ss tap, single lever mixer art base rising up to a horizontal swivel 'neck' for the main tap (with second on/off 90 degree tap at the end) and an outlet for the main tap.
Rising up above the main horizontal outlet is the attachment to a flexible hose in a large coil spring leading to a spray outlet which resides in a swivel holding arm projecting from the main body.
OK, I plumbed it in yesterday replacing an older leaking swan neck two valve mixer. I had isolation valves under the sink but instead of the previous soft copper tails this one has long flexible braided connectors so I used adapters after the isolators for go from 15mm copper to a half inch bsp screw to fix the flexibles to.
On refilling the system the cold works fine. The hot has vey little flow. I can only think that I have possible restricted it with some stray ptfe tape OR something else in the tap is introducing additional resistance on the hot side. (Mine is a hot cylinder with loft header tank system).
Now, when I put the main valve to mix flows and close the outlet at the end of the horizontal arm (ready to use the spray head) I can hear the cold flowing back up my hot pipes and if left on would eventually overflow the header in the loft I guess. Although it is less noticeable I think I get the same effect when just using the mixer tap normally (ie cold flowing back up the hot side).
What is normally there to stop this happening? I can imagine a non return valve on the hot side would possibly cure it but this is surely not an essential but unmentioned part of the installation.
Any helpful thoughts gratefully received.