K
kb76
Hi all, service one of these every year and occasionally get the a77 fault and lock out. Recently cut a remote vessel on return to boiler as internal one had gone and under sized for property (holiday home) Also changed o ring on pressure switch as was leaking. Went to check this week as guests going in today and now a77. Seems to happen more in colder weather from memory and when boiler left off or in economy mode. I know there's a condense sensor in the latent heat collector, can this furr up or go to open circuit when condensate cools down? Condense pipework from boiler all clear with air gap etc. Thanks Kevin