My 28i combi boiler is only working in either heating mode or hot water mode, this is to say i can have my heating on as long as I dont ask for hot water,soon as i ask for hot water it goes into lock out
What do you mean lock out?
You can only ever have one or the other, from heating, when you want hot water, a valve diverts the flow, switching back when not required. same valve operates even if heating not being used.
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