apollo 30 50b,no hot water

[hadwin]

i have an apollo 30 50b boiler and i need some help ASAP.the boiler works fine when heating is selected,buy when i select water constant the boiler does not fire up.i am only getting hot water by having heating on.any help/advice will be really appreciated

 

[Puddle]

Well does not sound like the boiler but the controls on the system,would think that maybe you should get someone in to check out the hot water motorised valve

imho

 

[hadwin]

is there anything i can do to test/check the valve,and where is it located