We have an external condencing, combi boiler, serving the heating and hot water.
We have a problem with air in the circulating pump, which we have to bleed daily before the boiler will reset and come on.
We have isolated the boiler before christmas (before the cold weather) and pressure tested the system, and the pressure held constant for 3 hours.
We have had Worchester out 4 times and they have change the pump every time, the AAV, the PCB, the diverter valve, and checked the preasure release valve and expansion vessel.
1. has anyone got any ideas what could be causing this?
2. the pipework to the boiler externally is in copper (insulated in a boxing stuffed full of more insulation). A soldered joint failed two winters ago, causing a similar problem. If we change this to Hep2O is it less likely to fail than copper, ie. is Hep2o better suited to external pipework than copper?