Any sparks? Trying to wire in new thermostat..

[DuraAce]

OK, basics - Combi boiler (Greenstar 25si) exisiting thermostat - Myson, new thermostat - BG Hive.

Current thermostat uses 4 wires, new Hive looks like it needs 5.



Above shows old thermostat wiring instructions.



Above shows existing wiring. L and N go to a fused 230v spur next to the boiler. C and 1 run inside the boiler.



Above shows new wiring requirements of new thermostat



Above shows internal wiring of my combi boiler. Can I run a cable from inside my boiler using these terminals to the Hive control panel? (L and N are fed from my fused spur). Can the LR, LS NS terminals in the boiler be run to the C, NC and NO terminals on the hive? Is is that simple?! which wire goes to which? Or can I do something with the C and 1 wires direct into the Hive? Where do I get the C wire from?

Any help would be greatfully recieved!

[DuraAce]

DrDeAtH said:

Don't use the 'heating off' terminal 2. Use t1 and t3
C and 1 should link across Lr and Ls inside the boiler already.

Without trying sound like a total idiot, can you put that into simpler terms for a simpleton like me?!

[DuraAce]

Legend. I'll have a crack over the weekend.

[DuraAce]

Rickyy said:

Ls from the boiler to L on the stat.

NS to N.

Make a link from L to common on the stat.

Then heating on connects to LR on the boiler.

I'm confused now (doesn't take much) but I'm determined to crack it and not pay a fortune to have it installed by someone!

Trying to follow your connection instruction..... Have I got it right so far?
HIVE......................................BOILER
N (perm neutral) --- Connect to NS on boiler
L (perm live) ----Connect to LS on boiler
1C (Common) ---- Linked to L in HIve box
2Heating off(NC) ----?
3heating on(NO)---- connect LR on boiler

Can I take the connections for L, N from my fused spur? Or must I run the wires out from boiler? What connects to 2Heating off(NC)? Or have I misunderstood?

Edited by DuraAce on Friday 4th December 17:31

Edited by DuraAce on Friday 4th December 17:33

[DuraAce]

Ok, I opened the boiler and the terminal block had the five connections as pictured above

N and L are connected to the 23ov fused spur on the wall. Ls connects to C on the old thermostat controller, Lr connects to 1 on the old controller. Ns has nothing connected to it.

Edited by DuraAce on Friday 4th December 18:28

[DuraAce]

280E said:

I think you should re-read the instructions:

"WARNING

Installation and maintenance to be carried out by suitably qualified personnel and in accordance with current wiring regulations"

Meh! Can't be that hard can it? I like a challenge.

Laplace said:

Am I right in assuming you have two fused spurs? One feeding the boiler and the other feeding the "relay box"? I assume that's why there's no neutral going out from the boiler on Ns as you described. In which case...here is my best dumbed down instructional

Nothing goes to Heating Off (NC).

Yes! There are two feeds from the fused spur. That's where (some!) of my confusion comes from. Makes sense now with your diagram

Thankyou! Very much appreciated.

Edited by DuraAce on Saturday 5th December 06:57

[DuraAce]

Laplace said:

lots of useful info pitched at exactly the right level!

Cheers buddy! Installed and works perfectly. Didn't even blow a single fuse. Thanks again, top man.

Part of my confusion was the two fused spurs, and the fact the new thermostat had five connections in it, I'd somehow convinced myself I needed something in all of them.

I've learned a fair bit and saved a few quid!

Edited by DuraAce on Saturday 5th December 16:54