I have an Ideal Classic RS260 wall hung boiler, a Honeywell ST6400 Programmer, a Honeywell Room Thermostat, a Grundfoss 15/60 Circulating Pump and a V4073A Mid-Position Diverter Valve in a 'Y' Plan.
I hope that makes sense!
My problem is this: I have plenty of hot water both upstairs and...