OK, so I've changed the capacitor for Farnell 1781894 (325v), tried a 400v 1uf capacitor, swapped the relays round, no difference. It may run the compressor, often doesn't. When t odes, it only runs for a few minutes, then cuts out. What am I meant to do to get consistent action from the compressor relay?! Fan relay circuit works fine, I even swapped the two relays round on the pcb, but the compressor still won't fire. Is there a rogue component before the capacitor that's messing this up?

many thanks (in anticipation!)

GrahamT, January 2016

I do not know this equipment but your issue seems to be inconsistent running of the compressor - either the compressor itself or the relay that switches it on and off?

As a diagnostic troubleshooting aid you might consider bypassing the relay circuit and powering the compressor with a couple of bits of wire - alternatively - rig up a tell-tale lamp (neon perhaps) to the output of the relay and see what's going on.

Good Luck..., January 2016