Hello All
A while back I asked why my CH wouldn't come on unless my HW was also operating, two replies pointed a finger at my 3-port valve.
Well, I finally got around to replacing it today and yes - pat yourselves on the back gentlemen, that was indeed the culprit!
Bigger job than I thought though - non-standard valve plates meant I had to drain the system and replace the valve itself as well as the controller. Thankfully both units used the same standard wiring colours, so swapping the electrodes was a piece of cake. (Just as well, I've inherited an overstuffed connection box with no markings or hint as to what goes where)
Running nicely now, thanks!
BTW, unrelated but rather than start a new thread - quite a nice diy site that doesn't seem to have been mentioned recently, if at all. Useful for new/mid range DIYers, well written and easy to understand without being patronising. No connection, just found it useful for speedfit clue.