I'd like some help with a problem that has occurred fairly recently with a shower system
The shower is gravity fed to a mixer bar, and seemed to work fine until the old boiler gave up the ghost. Since the new boiler was fitted (which otherwise works fine), there has been a problem where the shower pressure gradually drops over time (even from the start of one shower to the end) until it is little more than a dribble.
Common sense would suggest (at least to the uninitiated) that this is an air lock, but we cant find one. All joints have been loosened and allowed to run with no effect APART from the feed into the mixer bar. When this is opened and left to run, air can be heard in the pipes, and once this has run through the pressure is OK (if still much lower than before the boiler change) for a while before it drops again.
There is no change in temperature, only pressure. Checking the pressure in the taps when this is symptomatic shows that they are fine.
We thought this might be due to the fact that the shower feed pipe was above the hot water header tank (2), shown as (a) in the first picture, so lowered it to below the feeder tank, shown as (b) in the second picture, but this has made little or no difference.
To connect the shower and tap pipes lower down than the loft would mean major work under the floors, which is why we have not done that yet, but any other suggestions would be gratefully received.
Thanks in anticipation