Another hive and combi boiler Query

Hi I have read lots of threads about installing a hive unit to my combi boiler, its a ( Vaillant ecoTEC pro 28 ) I have connected the unit up at the boiler using the existing wiring with the link between L and 1 and switch wire out from 3 ( seems to be the correct wiring according to these forums )but it will not fire up at all. green lights on the unit and hub but nothing is happening
when i remove the stat and put the original back on it works no problem. all I done was connect the cables like for like but it will not fire up the boiler
would it be something to do with the hive set up or do i have to do something with the settings in the boiler to get it going.
thanks for your help lads
oldspark

From the limited information you give that sounds reasonable, provided that you have the Single Channel Version of Hive and that the boiler is wired for 230V control and not 24v.

If you are just wanting to remove an old thermostat and move the existing wires from it to the Hive receiver, then you need to provide details of the existing thermostat and the wires going to it for a definitive answer, this is because there are several different methods of wiring them.

On the other hand, if you are wiring the Hive directly to the boiler, then again there are several variants of Vaillant ecoTECH connections as they have changed over time, but if your version has terminals like below and you have removed the existing thermostat wiring, then:



OPTION 1*

Hive L & N connects to L and N

Hive terminals 1 & 3 connect to boiler 3 & 4 where the 'bridge' is shown above

Do not add a link between L & 1

or:

OPTION 2*

Hive L & N connects to L & N above

Hive L and 1 are linked

Hive 3 connects to boiler 4

*You should only do this if you can access the boiler terminals without opening up a room sealed compartment to get to them. Othewise it's a job for an RGI who can make the necessary safety checks afterwards.

If the boiler has integral time control this should set to be permanently on 24/7 otherwise it will interfere with the operation of the Hive.
If your boiler connections are different to above, post back their details and someone will be able to advise further.

What thermostat have you replaced? What year of pro 28? It’s on the serial number underneath, first 4 numbers.

Thanks for the replies I will be back with more information possibly at the weekend