We have a Baxi combi boiler which was working fine and then, without any changes to the system, there are not 3 different scenarios:
* some taps and showers run intermittently hot and cold
* there are 2 taps which run perfectly OK
* 1 tap which doesn't trigger the boiler to start at all
Seems like a flow problem - so we had the flow switch replaced. Same issues.
Changed the heat exchanger - same issue.
The water pressure is good and the flow from all taps, even the one that doesn't trigger the flow switch, is good.
The boiler was serviced within the last couple of months.
Our plumber is at a loss to know what the issue can be - has anyone had similar problems and found a fix?
Thanks for any thoughts / guidance.