Start/stop Start/stop on/off on/off

Hi There,
I have a boliermate2000, never had any problems until last year where the ACB Board packed up, my plumber replaced this and every thing was fine.
now my boliermate2000 sounds like a pump is trying to start, it goes on/off on/off on/off, its like a starter motor turning over in a car but not starting. sometimes its fine then other times its not, sometimes the waters hot then cold then hot, sometimes the heating comes on other times not. its so annoying!!! Arrrrh
The lights on the ACB board when its playing up, flash on and off in time with the pump?
If I turn the boliermate2000 off for a few minutes then back on (dads Idea) it fires up, for a while then goes back to on/off on/off on/off
any one have any ideas?

Thanks Sarah

Really does sound like the Main board.
Make sure when fitting that it is NOT touched with fingers etc. Static!
Mike