Hi guys, I have a problem with our Grant 90 MkII Oil Fired Combi boiler in that there is only hot water from the hot water tap if the central heating is on or made to come on by turning up the room stat till it clicks the heating on.
I tested the microswtich that is pressed by the pin attached to the diaphram in the diverter valve and the boiler fires up when the microswitch is pressed manually. So I then I tested the movement of the pin and although it moves outward when the hot water tap is turned on, it doesnt do so far enough to operate the microswitch. I overcame this for testing purposes by packing out the microswitch with a spacer so that even though the pin doesnt come out far enough it still operates the microswitch so the bolier fires on demand whenever the hot water tap is on.
Soon as I did that I thought that would be a temp fix however, the odd thing (or the thing that seems odd to me) is that even now I have managed to get the boiler to fire when the hot tap is turned on, the water still runs cold until I go to the room stat and turn the heating up far enough to cause the rads to heat up and when I do this the water runs perfectly hot.
The moment I turn the room stat down so the central heating clicks off again the water starts running cold again even thought the boiler is still firing and continues to fire until I turn the hot tap off again.
Anyone any idea whats happening here and whats at fault?
Many thanks.
I tested the microswtich that is pressed by the pin attached to the diaphram in the diverter valve and the boiler fires up when the microswitch is pressed manually. So I then I tested the movement of the pin and although it moves outward when the hot water tap is turned on, it doesnt do so far enough to operate the microswitch. I overcame this for testing purposes by packing out the microswitch with a spacer so that even though the pin doesnt come out far enough it still operates the microswitch so the bolier fires on demand whenever the hot water tap is on.
Soon as I did that I thought that would be a temp fix however, the odd thing (or the thing that seems odd to me) is that even now I have managed to get the boiler to fire when the hot tap is turned on, the water still runs cold until I go to the room stat and turn the heating up far enough to cause the rads to heat up and when I do this the water runs perfectly hot.
The moment I turn the room stat down so the central heating clicks off again the water starts running cold again even thought the boiler is still firing and continues to fire until I turn the hot tap off again.
Anyone any idea whats happening here and whats at fault?
Many thanks.