I posted a couple weeks back on here about problems with my central heating pump and 3-way zone valve not opening when I selected heating on my programmer, but the boiler was starting. So after some great advice off cjb1971, I linked out the red and yellow wires on the wall thermostat (Honeywell T6160B), this started the pump and opened the 3-way zone valve. So I decided to get a new wall stat and went for a digital Honeywell CM907 7 day timer hoping to have better control of the heating, i.e. just leave the programmer on all the time and let the wall stat control when the boiler, zone valve and circulating pump started. I wired the CM907 as shown on the wiring diagram.
Red live wire to pin B, and yellow wire to pin A. And taped up the redundant blue wire.
My boiler is just an old Thorn EMI backboiler, with a hot water cylinder, header tank in loft, 3-way Honeywell zone valve, Honeywell ST699 programmer, and the stat mentioned above. I have a feeling that something else is maybe wired up wrong in this old system, as mentioned when I had the original faulty wall stat the boiler was firing but the zone valve, pump were not running. Now with the new stat fitted the boiler is firing when told to by stat and the zone valve is opening, and pump running, but when the CM907 is not asking for heat (room temp below setpoint, flame icon off on the control display) the boiler is still firing at various intervals (with only heating set at On, on the programmer), but the zone valve and the pump are not starting. Unless it is the programmer as I have had trouble with these in the past, otherwise I have feeling that the system has maybe been wired incorrectly from day one. But then again I am obviously no expert. Any help please??
Red live wire to pin B, and yellow wire to pin A. And taped up the redundant blue wire.
My boiler is just an old Thorn EMI backboiler, with a hot water cylinder, header tank in loft, 3-way Honeywell zone valve, Honeywell ST699 programmer, and the stat mentioned above. I have a feeling that something else is maybe wired up wrong in this old system, as mentioned when I had the original faulty wall stat the boiler was firing but the zone valve, pump were not running. Now with the new stat fitted the boiler is firing when told to by stat and the zone valve is opening, and pump running, but when the CM907 is not asking for heat (room temp below setpoint, flame icon off on the control display) the boiler is still firing at various intervals (with only heating set at On, on the programmer), but the zone valve and the pump are not starting. Unless it is the programmer as I have had trouble with these in the past, otherwise I have feeling that the system has maybe been wired incorrectly from day one. But then again I am obviously no expert. Any help please??