BDR91 wiring on a Biasi Boiler

[kg911]

Hello everyone,

I recently bought a house which came with a Biasi Riva Plus HE 28C ERP Combi Boiler. I would like to install the BDR91 to the boiler but I would need some help with the wiring. Below is the manual of the boiler showing the connections for the external control.

and here is the actual picture:

And here is the wiring diagram for BDR1:

As the diagrams suggest, the link N should be removed from the boiler and 1, 3 should be connected to BDR91's A and B. Right?

How about the mains supply to BDR91? The boiler is powered directly from a fused spur isolation switch (cable coming out of the wall). I know this should be from the same spur switch. Should I use the N,L from the Boiler?

Many thanks in advance

Costas

 

[stem]

You have worked the wiring out correctly. However, if you have to open up the room sealed boiler compartment to access the boiler wiring terminals you should not do this. Only a gas safe engineer should do this as he will be able to make the necessary safety checks afterwards.

 

[kg911]

Many thanks for your reply stem,

What I did was to put a juntion box after the spur switch, from where I powered the BDR1. I connected the BDR1, paired with Evohome controller but it doesn't fire up the boiler. Hot water works fine and boiler fires up.
The BDR1 connection is a follows:

As said, the BDR91 is powered from the junction box. Then A was connected to 1 and B to 3 in the boiler. Any ideas about the cause of the problem?

 

[stem]

The wiring looks correct. The thermostat is just a switch when the heating is 'on' the wires in A & B are joined together internally (which replicates what the black link was doing)

Check that the wires are secure and that the screws are in contact with the conductors and not the insulation.

Are the indicators on the BDR91 working?

What happens when the manual override on the BDR91 is operated.

 

[kg911]

Thanks for your prompt reply. I will double check the cables. The boiler doesn't fire up manually.

 

[stem]

If that doesn't work, as a test, at the BDR91 put the blue wire from B in with the brown wire in A. Try the boiler now, does the heating come on? There's no need to replace fit the thermostat on the backplate when doing this test.

This will check the wiring between the boiler and BDR91, if the heating comes on then then that part of the wiring is OK.

 

[kg911]

Hi stem,

It works! I had to set the timer off. Many thanks for all your help.