Help! New WiFi/RF thermostat wiring

[hadippy]

Hi. I have a new tuya smart WiFi/RF thermostat that I cannot get to fire the boiler (ideal instinct 30) when it calls for heat. The old thermostat was a Honeywell (t40?).

I have wired up the neutral and live and have connected the thermostat wires from the boiler to com and open on the new thermostat.

It has power and when I increase the temperature the thermostat heating light clicks and displays but the boiler doesn't fire.
Have attached the original woring layout of old thermostat
Any suggestions??

 

[EFLImpudence]

I cannot make out the picture well enough, but first:

Have you set the boiler timer to always on?

 

[CBW]

There’s only 3 wires and earth on Honeywell, but you’re stating Live and neutral then boiler wires?

 

[hadippy]

The "earth" seems to actually be a neutral. Even though it was attached to earth on the Honeywell!

5 wires actually come off the boiler but only 4 to to thermostat.
The boiler is set to always on.

Have attached the wiring diagram for new 'stat

 

[flameport]

The "earth" seems to actually be a neutral.

It isn't, and whatever wiring you have on the new device is wrong.

 

[hadippy]

It isn't, and whatever wiring you have on the new device is wrong.

SO how should I wire it?

 

[EFLImpudence]

The "earth" seems to actually be a neutral. Even though it was attached to earth on the Honeywell!

Well, yes, it would be, wouldn't it? but you can't use it for a Neutral.
The terminal on the Honeywell is just somewhere to put it; it doesn't do anything.

5 wires actually come off the boiler but only 4 to to thermostat.

What have you connected them to?

The boiler is set to always on.

Ok.

Have attached the wiring diagram for new 'stat

No, you haven't.

 

[hadippy]

Well, yes, it would be, wouldn't it? but you can't use it for a Neutral.
The terminal on the Honeywell is just somewhere to put it; it doesn't do anything.


What have you connected them to?


Ok.


No, you haven't.

Have edited post to fix picture attachment issue

 

[RandomGrinch]

SO how should I wire it?

5 wires actually come off the boiler but only 4 to to thermostat

Can you show us a good picture of the connections in the boiler?

...but without seeing the connections, probably...

Blue to Neutral
Brown to Live
A small link wire between Live and Com
Black with brown sleeve to Open

And safely park the earth.

But given the previous comments, we could really do with seeing the boiler connections to confirm...

 

[hadippy]

Can you show us a good picture of the connections in the boiler?

Best I can do

 

[RandomGrinch]

Best I can do

Sorry, you may have missed the edit to my above post.
The connections I listed above should theoretically work..
BUT, there is a grey wire that is probably live, that we can not see how it has been terminated.
Do you know where the grey wire ends up?

 

[hadippy]

Sorry, you may have missed the edit to my above post.
The connections I listed above should theoretically work..
BUT, there is a grey wire that is probably live, that we can not see how it has been terminated.
Do you know where the grey wire ends up?

The grey from the boiler is the blue at the thermostat

 

[EFLImpudence]

Which model is the new thermostat?

 

[RandomGrinch]

The grey from the boiler is the blue at the thermostat

Ok, so what wires do you actually have at the thermostat (under the sleeving)? and does the cable go directly from the boiler to thermostat, or are there any junctions between the cables, such as in an FCU?

 

[hadippy]

Ok, so what wires do you actually have at the thermostat (under the sleeving)? and does the cable go directly from the boiler to thermostat, or are there any junctions between the cables, such as in an FCU?

There is a brown (with black under), yellow/green, blue (with grey under) and just brown.

The cable from the boiler appears to go through a spur/boiler switch and then to stat.

The new stat is a tuya r9b.