BDR91 Install, No Power

[Mathew Lawson]

Hi All,

I have a Worcester 28si Combi Boiler, my current thermostat is a T6306 and I am replacing it with an Evo Home.

When I isolated the power, removed the existing stat I found three wires connected; the wires were a perm live, switched live and a Neutral - the existing wires were located in the following terminals on the T6306:
Perm Live - 1
Switched Live - 3
Neutral - 2

I fit the BDR91 and setup the wiring as follows:
Perm live - first L terminal
Neutral - N terminal
Switched live - B terminal
and I then linked the second L terminal to the A terminal.

I fit the PCB cover, turned on the power to the boiler which was fine but the BDR91 had no lights active (no power) I tried holding down the button to get into sync mode with the Evo but again no power.

I thought maybe the BDR was dead so I went and purchased another but again in the same setup the boiler had power but the BDR didn't so I could call for heat.

Does anybody know what I can do?

P.s I set the boiler to always on and not on a timer.

 

[D_Hailsham]

What does the other end of the thermostat cable connect to?

 

[picasso]

If you have a multimeter check to see if you have 240vac at the bdr.

 

[Mathew Lawson]

Thanks for the reply, I have a multimeter and should of said, the cable going into the first L shows power when connected to the BDR; when it was connected to the T6306 it also showed power when connected to terminal 1 (I should of mentioned that in original post so please accept my apologies).

To be honest I don't want to mess with the boiler wiring which is why I set boiler to always on and linked second L to A.

 

[picasso]

have a look and see if you have bent the pins on the back of the bdr.

 

[Mathew Lawson]

no bent pins, both BDR's (original and new one I bought thinking the first was dead) are pristine; no bent pins or damage.

 

[D_Hailsham]

Remove BDR from backplate and link A to B (leave L to A link in place). The boiler should light.

If it doesn't move the L/A link to the other L terminal and try again.

 

[Mathew Lawson]

Is it safe to have all those links?

So to confirm, try:
Neutral to N
Perm Live to first L
Link second L to A
Switched Live to B
Link A to B

 

[D_Hailsham]

Is it safe to have all those links?

So to confirm, try:
Neutral to N
Perm Live to first L
Link second L to A
Switched Live to B
Link A to B

I didn't say that, the rest is correct.

I did say that if the boiler still did not light, try linking the first L to A, instead of 2nd L.

If the boiler now works, remove the link between A and B (leave link between L1 and A), replace BDR and check if boiler works.

If it doesn't, the BDR is faulty.

 

[Mathew Lawson]

Sorry, I am confused because I don't know where you want me to put the switched live?

 

[D_Hailsham]

Sorry, I am confused because I don't know where you want me to put the switched live?

Senior moment!

Switched live does go to B.

Linking A to B just mimics what the BDR does when the green light goes on.

 

[Mathew Lawson]

Ok I tried this and still nothing so I purchased a 3rd bdr91 and still the same so it can't be the bdr91... I must be missing something.

When it's connected I am getting power on the live and the second l linked to a

 

[picasso]

Are you changing the back plate each time ?

 

[Echo the husky]

If you remove the stat completely for a moment and join live to switched live with a connector block I assume the boiler starts??

If so do you have full 240 or so volts between live and neutral?

 

[Mathew Lawson]

Yes I'm changing the back plate each time, using fully the newer bdr each try.

I connected the perm and switched live to each L terminal and boiler started. I'm getting 258v across the live?