I have a 2 zone system, with a dedicated DHW circuit. During the summer mon
ths the system works fine, but as soon as winter arrives and the system sta
rts supporting the in floor heating zones it gets a period Err that leaves
the system circulating the DWH pump but the boiler does not start.
To clear this I need to hit the reset button, the boiler immediately fires
and the system runs normally for a few days until the Err reappears.
There is some correlation with this error to moving from summer operation,
DHW only to winter operation supporting the heating circuits.
Is this a configuration issue, or a controller malfunction?