OK I agree with your statement above but I need further information if you have a specific question -
a. Which model of Altech are you using?
b. Which make and model of boiler are you using - some boilers use a switched 24 volt supply some 230 volt supply?
OK you have already got an answer from PlumberPro what more do you need??
OK if you can go back to the original question with Plumber pro we can continue on that thread (I have responded) and then I can get the other two info requests cancelled and refunded.
Do you require further assistance with this I am waiting for you on the original information request??