HW or CH but not both at the same time

[Matt_K_b]

I have a conventional boiler / hot water tank configuration in my house but the problem is that I can have either HW or CH but not both at the same time. The control / timer unit is the type that controls HW on left (with 'off', 'timer', 'once', or 'on') and CH on right with clock in the middle.


During the summer the boiler has heated the HW tank but with this odd requirement. Every day when the boiler should come on I have had to cycle the CH through from 'off' to 'on' and then when I click it to 'off' the boiler fires up and heats the tank before turning off when the desired temperature is reached.


Now if I set both HW and CH to 'timer', when the time is right nothing happens again. I have to cycle either HW or CH to 'off' (advancing either doesn't work) and then the boiler fires up and provides heat to the one that is selected to be on.


So the boiler works and provides heat to either CH or HW but not both. This behavior, which requires my manual intervention with the controls, only started this spring and I don't fancy having to do this all winter (I'll be the one who gets up in the morning to turn it on whilst the family sleep).


I'll probably get someone to look at it but just wanted to see if anyone else had experienced this sort of behavior before and had any suggestions?

 

[jtsplumbing]

If everything else is working ok, it could be you have a faulty programmer !