honeywell cm927 to valliant 937

[stem]

To me it looks like there is a wire in RT, I think I can see just see a mm of copper and the edge of the insulation, but you're right it's not very clear.

I can't tell where the brown wire in the terminal next to it goes. It could be looped to L or the one leaving top right of the shot.

 

[Jag-1978]

I promise to upload a better picture shortly when I get home from work..

In the mean time i took a recording of the boiler behaviour via Live Data.. I've added 2 videos if you guys can have a look which might identify what the issue could be. I'm starting to think maybe it's not the thermostat that is causing the problem but something else.. I've only got Status S numbers to go by I'm not getting any F Fault codes Worth watching both videos start to finish so you can see the full compliment of status codes Also left the Audio so you can hear the clicking in and out randomly..

thanks in advance:

https://imgur.com/9eGSTQ9

https://imgur.com/v6MnSVK

 

[CBW]

Seems like it’s not the thermostat.

• Had any work carried out recently?
• Check the flow and return valves underneath the boiler.
• Do you have any zone valves? Check these are functioning correctly.
• Check the 24v link hasn’t been left in.

 

[Jag-1978]

no work carried out recently to be honest
both flow and return values are as they have been nothing changed there..
I dont use Zone valves. Each Rad has a thermostat but again nothing changed there..
Not sure about the 24v link and what I'm looking for there but will have to investigate

thanks

 

[Jag-1978]

If you disconnect it the boiler will do nothing from a central heating aspect, the heating just won't work at all. If you were to move the wire from thermostat B and put it in A with the wire already there, then the heating will be 'on' permanently. If then the boiler runs continually and there's no S.30 message, all is well with the boiler.....you might find it gets a bit warm though.

I moved the wire from point B to A on the stat receiver and powered up the boiler and it made no difference Still showing the S.30 status message.. Does that indicate a dodgy receiver?

 

[Jag-1978]

Afaik, that side doesn’t do anything, so I don’t know why it’s bridged, which is what I queried in post #8 and @ianmcd in post #12. Can you post a better photo as requested?

As promised here is another angle with the wires more obvious let me know your thoughts:

x2 Brown wires in the first port on the left
x1 Blue to to RT

x2 Brown to L
x1 Blue to N
x1 Green/Yellow to The right most port

 

[CBW]

Do you have any test equipment? Eg multimeter, or 2 pole voltage tester?

 

[Jag-1978]

Do you have any test equipment? Eg multimeter, or 2 pole voltage tester?

I have a multimeter and voltage tester somewhere yes..

 

[CBW]

Dig them out to test for voltages. Linking the 2 wires together should have worked, so it’s either not receiving the correct voltage, or the pcb is goosed.

 

[Jag-1978]

Dig them out to test for voltages. Linking the 2 wires together should have worked, so it’s either not receiving the correct voltage, or the pcb is goosed.

okay will do some checking thanks

 

[ianmcd]

The brown link between L and the RT connection and the other brown in the same terminal is wrong, shouldnt be anything in there , you need to find where that other brown wire is connected to

 

[CBW]

The brown link between L and the RT connection and the other brown in the same terminal is wrong, shouldnt be anything in there , you need to find where that other brown wire is connected to

Looks like they’ve linked the L across to the blank side, possibly using it as a connector, and then to the A on the receiver? Then blue switched live back on then RT side?

 

[Jag-1978]

I'll have to do some wire trailing and figure this out and come back to you guys... It's just odd that it seems to work at random times.. Like for instance.. All night it was perfectly fine and i had good heat.. then randomly about 5am the heating had gone.. nothing consistent about it as I didn't have heating the pervious couple of nights.. Thermostat is set to remain on constantly so nothing to do with that.. I'm now dubious about the wiring of the stat to the boiler.. I'm thinking of getting a Nest Stat so maybe a good idea to get that into play and have it wired properly..

 

[stem]

If the wires haven't been changed and it's been working as it is for a long time previously, then sound to me that the wiring isn't the issue.

Did you try the test I suggested?

If you were to move the wire from thermostat B and put it in A with the wire already there, then the heating will be 'on' permanently. If then the boiler runs continually and there's no S.30 message, all is well with the boiler.....you might find it gets a bit warm though.

 

[Jag-1978]

If the wires haven't been changed and it's been working as it is for a long time previously, then sound to me that the wiring isn't the issue.

Did you try the test I suggested?

Yep i think i did reply to your message. I moved the Wire from B and put it in A, and rebooted the boiler and it was exactly the same no change.. it didn't make any difference at all.. Was still showing the S.30 code. however randomly pre wire change it was exhibiting random status code behaviour as shown earlier in the videos i posted.. Thanks for the suggestion, it was the first thing i tried