Fitted new external timeswitch to potterton promax 33he and now heating won?
Fitted new external timeswitch to potterton promax 33he and now heating won't fire up. I have wired in a horstmann c17 series2. The existing integral time clock works when I put it back in, I have checked the new times witch is sending current to the pcn but it still doesn't fire, please help.
Darren
Darren
January 2014