I've bought an ST6400S programmer off ebay which I'm intending to use to replace a faulty ST6400 (no "S"). All well and good, I shouldn't even need to use the new backing plate, just remove the old panel and drop in the new one. The snag is that I've only just realised that the "S" means "Service" and that this has a mode which can be used to lock out the programmer after a year so as to enforce a service call and hence prompt a boiler service. This behaviour is selectable but Honeywell don't say in the instructions which is the default mode. I therefore need to get into "installer mode" which apparently is done by a combination of button pushes but Honeywell keep them a secret from the general public. Does anyone know (and would be willing to share) the access code for this?
Thanks, Calvin