Drayton Wiser WT724R Hub

[Moon_Fire]

Maybe there's an alternative though.

Link your boiler's thermostat inputs together (so that it would be permanently ON), then disconnect the boiler's main's Live feed and connect it to Pin 4 on the WT724R instead. When the Wiser hub calls for heat, 230VAC would power the boiler directly and since its thermostat inputs are shorted, it should power up.

It wouldn't work this way because the boiler also provides hot water.

 

[Moon_Fire]

That sounds technically plausible, but I think it might prove quite tricky/fiddly in practice (just from a soldering point of view). There's a possibility that the drive transistor could be overloaded, if the old relay is left in-situ as well. The data sheet for the existing relays is HERE (the 24VDC version).

Well I was thinking no soldering as in there are relays available to be bought that provide what I need: making the automation less smart. I'd incase it in a box of sorts and have 2 wires in that come from the Wiser Hub and 2 wires out that go to the CH panel.

I had a thought on my idea about controlling the boiler directly via Pin 4.

Though it should work for old gas boilers and any oil boiler, new gas boilers contain a lot more electronics and may not like being frequently power-cycled; they may go through a lengthy initialisation. (I don't have one, so I don't know).

Mine has a fairly amount of electrical stuff in it and indeed does powercycle for a minute or 2. So it wouldn't work for me as mentioned above.

Another idea:

The Wiser output feed would normally drive a motorised valve. (I don't know if these are common in Romania), but they have a small motor that turns a valve and when it reaches a certain position, a microswitch is activated. That microswitch is normally used to send power to the boiler / pump, rather than the Wiser itself.

You can buy replacement actuators for these valves (containing just the motor and switch(es). There are lots of different brands, but this Honeywell version was one of the cheaper ones I found. There is a datasheet (for the entire valve) HERE. (You wouldn't need the actual valve part).

Electrically it's inferior to the other relays I linked to (too many moving parts!), but at least it's the sort of thing you might expect to find connected to a boiler

I'd have to think about it. I wouldn't invest much money on a workaround when I can buy what i need for a fair price.
In all fairness, I got this Hub from a friend for free that's why i want to use it but not if I have to make hazardous modifications.

 

[Moon_Fire]

On that hub, Pin 4 goes LIVE (230VAC) when there is demand for heat. So I would say just PIN 4 and Neutral direct to the Boiler&Pump. (Assuming there are no motorised valves that need to be energised).

I think

So I talked to my friend and he definately told me we can use a r,elay that's connected to Pin no. 4 and acts as an interface for the 12V (I guess) circuit that needs to be closed for the CH to start.
Once again, I feel the need to reiterate that I am in your debt!