Hi all, As the title says, my central heating only comes on when hot water is active. I'm an amateur so apologies for the sparse info or incorrect terms. We have a boiler and hot water cylinder that is controlled by a Hive system. One admission is that the Hive was installed by a relative and he didn't have time to check all the wiring (lockdown happened and changed a lot of plans). One of the outstanding issues was that the original wall mounted thermostat needed to be wired for the heating to work at all. Anyway, it's been functioning exactly as expected for the last 5 months but earlier this week I noticed the heating wasn't coming on no matter what I did with the hive settings. So I tried the basics of checking the boiler, the hive itself and then looked in the airing cupboard but could see no obvious fault except that the motor for the 3 port valve was on constantly with a buzzing noise. Long story short, a plumber did come by to diagnose and did a next day job to replace the fault 3 port valve and motor. However, the same problem was still persisting; the heating will not come on until the hot water was set to go. Furthermore, the hot water needs to be actively required (level low or temp not reached) otherwise nothing happens for the heating. I can see clearly the heat pump only activates when the hot water is engaged. We do have an electrician coming out hopefully soon but my google research is only giving me limited answers, any ideas what's happened given most people solved their issue with replacement of the 3 port valve? Thanks for any advice in advance.