Hello, i tried posting this earlier but it wouldnt work so apologies if this has appeared twice. Ive just had a Park Lane (Bathroom Brands International Ltd) thermostatic shower valve installed in the bathroom on the 1st floor (not had a shower valve in place before this one). Ive got a combi boiler on the ground floor whilst the bathroom is almost directly above on the 1st. The boiler is a Ravenheat LS80T combi (yes i know its not exactly a great one but its actually cone ok for the money spent on it-i cant complain too much). No cold or hot water tanks are installed anywhere in the house. all taps in the bathroom (basin and bath) are connected via 15mm copper piping to he mains or combi and hot and cold flow is pretty good everywhere. However i get hardly any water (not even enough to spark the combi) out of the shower valve when it is turned on (in any configuration, all cold, all hot of any point between the two), no other taps are on when ive tried it. The shower valve is almost the same distance from the boiler as the basin taps except that the shower valve is 1.5 ft higher. Is the increase in height the cause for such a drastic reduction in flow or shoudl i consider getting the valve replaced under the warranty? The only other thing i can think of is there are approx six 90 degree turns in the piping from combi to the basin taps but about 9 to the shower valve (and all of the extra turns to the valve are in the last foot or so). The mains comes into the house on the ground floor on 15mm (where the stop cock is anyway) so would changing the h/w piping from the combi to the shower to 22mm actually make a difference? I wanted to see if the valve was faulty but the piping to it has been cemented and tiled in and there isnt enough play to pull the piping out after unscrewing the unions, also there are no check valves in the piping to the shower valve so i cant turn off the h/w or c/w separately in order to test in situ. Any advice on what i can try without having to rip the valve out would be much appreciated! Ive been waiting ages for the valve to be installed so its a pain in the butt that it doesnt, after all this time, i cant use it.