Recent content by Number34

Thanks for the prompt reply. In the meantime I've had the following diagram sent from Honeywell technical support, the number 4 connection on the programmer is shown connected! Any comments? It also happens to be the way I have my system setup at present. Can I assume that if I leave it like...

Simond, I've just fitted a CM927 to my system that has an ST6400C programmer. Two questions I'd like to ask: 1 - If I keep the ST6400 how do I set the heating side? 2 - Or should I replace it with an ST9400C ? Thanks.