in ch and dhw mode;
boiler star, pump start working, but when boiler demand for fan to ingage, fan doesn't come on, I cheched fan Terminals, there is no power there.
I cheched the micro switched for DHW and CH both make the connection, but fan doesnt come on.

David, July 2008

first check the boiler and hi limit stats are ok, then check the aps isnt faulty (stuck in nc position)

if not, may well be a pcb issue.....my money is on the aps

T, July 2008