New froststat clicking/lighting up but no response from boiler

[RandomGrinch]

here is the old honeywell, brown was in t 1 (top right), blue t 5. Does this help to solve?

It might, if the Honeywell had a terminal 5!

 

[Ron S]

wiring diagram again for the Greenbrrok TH90F

 

[Ron S]

Random, the instructions do not mention using terminal 3. Just neutral to 4 and connecting to mains which it seems to suggest to 1 on the diagram? Maybe the blue is permanent live.

 

[RandomGrinch]

Random, the instructions do not mention using terminal 3. Just neutral to 4 and connecting to mains which it seems to suggest to 1 on the diagram? Maybe the blue is permanent live.

What terminals were the wires connected to in the Honeywell - it is important to use the numbers actually marked on the unit.

 

[EFLImpudence]

 

[Ron S]

sorry the honeywell had brown in t1 (top right) and blue t3 (not 5). Im wondering if the brown is the switchable live. What is the "M" in the greenbrook instructions?

 

[RandomGrinch]

the honeywell had brown in t1 (top right) and blue t3 (not 5).

Your old Honeywell did not have a neutral connection.

you have a live and a switched live

Just because the wire is blue, doesn’t make it a neutral wire.

Instead of using terminals one and four, you need to use one and three.

What is the "M" in the greenbrook instructions?

M just denotes the load to be powered, it could be a boiler, or a 'M'otorised valve, pump, etc.

 

[Ron S]

Thank you. So is the brown likely to be the permanent live? - This to 1? Switched live to 3? I can voltage test each wire.

 

[Ron S]

The Honeywell is saying N by terminals 2 and 3, can you explain what these N's signify?

 

[RandomGrinch]

Thank you. So is the brown likely to be the permanent live? - This to 1? Switched live to 3? I can voltage test each wire.

Yes, but in this case, as there are only two wires, it doesn't really matter which goes into 1, or 3!

 

[Ron S]

So the frostat terminals are compatible between maes in terms of the numbers? Thank you for clarifying.

 

[Ron S]

I mean different makes?

 

[Ron S]

Greenbrook says a neutral is needed in 4 to operate the light, does this mean I will not have the light come on?

 

[RandomGrinch]

The Honeywell is saying N by terminals 2 and 3, can you explain what these N's signify?

You see the big rectangular block after terminal 3 - this again represents the load to be powered.
You have a switched live going to one side of the boiler, and a neutral connection to the boiler.
Again, there is no neutral connection to the stat.

 

[RandomGrinch]

operate the light, does this mean I will not have the light come on?

Yes, there will be no light, unless you rewire it with a neutral.