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No hot water

Hi I got an extension kit recently - the heating is working but the hot water doesn’t. I have a horstmann channel plus h37XL controller. Is there a certain way to wire this up. I’ve 3 thermostats - ground floor and then 2 on the 1st 2nd floor that are controlled by a separate zone - then the hot water. The heating is working fine just can’t get the hot water to fire up. Any suggestions would be great


  • Do you hear the relay click when you turn on the hot water?

    I assume your system has a zone valve for the hot water. If you do, can you confirm that power is being applied to the valve once the relay clicks on?

    What should happen is that the extension kit relay closes to energise the feed for the zone valve. valve opens and then energises the boiler and pump to provide heat.

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