Hello. I have an issue with my Honeywell ST9400C and would appreciate any advice. I have set the Heating and Hot Water to come on at the same time in the mornings - unfortunately the Hot Water comes on but the heating is overridden. The heating light comes on (on the st9400c unit) but the pump does not kick in. The heating does work independently as I have it programmed to come on in evenings (without hot water). I can't find any info anywhere to tell me the two can not be used at the same time. The control valve is set to automatic. The thermostat works fine and is set to a high enough temperature to switch heating on.
Any help much appreciated.
Any help much appreciated.