I am trying to wire a honeywell st9400a programmer to a Grant Vortex Combi 21 I have two wires coming from boiler one for hot water and one for central heating do I connect these wires to the on connections and what are the off connections for.
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local