Center wireless thermostat knackered?

[JP2020]

Current situation ...

Valiant EcoTEC Pro 28 boiler
Center wireless thermostat

Hot water still running OK
Central heating won’t start

Thermostat sends a signal to the receiver box if I run with manual / auto (green light appears on receiver) but then I get the wrench symbol and S30 error code on the boiler display

if I set the thermostat to off, the wrench symbol and error code disappear and the green light turns off on the receiver.

Chimney sweep mode worked so central heating seems fine.

wired up OK I think - live / neutral to live / neutral in the boiler
A / B from relay box to the 24V RT on the boiler PCB

Previous engineer who installed my boiler had wired it as L/N to L/N
Then I think he had a C loop from second L to A

I presume the my relay box isn’t sending the correct signal (if any) to the boiler and I therefore need a new thermostat and relay box (or just a new relay box - but I know they’re hard to come by alone).

just wanted to make sure this was the case before I buy a new thermostat.

thanks in advance!
Josh

 

[CBW]

S30 isn’t an error code, it’s a status code, stating that the boiler is waiting on the room thermostat to operate the heating. Wrench sign is either needs a service or lack of pressure in boiler.

What’s your pressure at? What temp is thermostat set to? Post photos if you’re unsure.

 

[JP2020]

Cheers for the reply

Pressure is OK, between min / max
I can bump the thermostat up to max but no change

 

[CBW]

Not had many dealings with 24v, but it might be the same, the return signal might not be being sent, but it could also be pcb, though unlikely. You might be able to test with a multimeter.

 

[JP2020]

Apologies, talking *******s. See attached.

View media item 105307View media item 105306View media item 105305View media item 105304View media item 105303View media item 105302View media item 105301
Is it correct that L/N is wired to L/N, A/B to -/+ on the BUS?

Seeing as the wrench sign only pops up when I switch the heating on via the thermostat, could it be that it’s putting a block on the heating mode until the service has been cleared?

 

[CBW]

Did this ever work? That’s wrong pcb end, ebus only compatible with Vaillant controls. RT next to it 24v is the one it should be in. Good job it wasn’t 230vac switching. Also 26.9 checks need to be done.

 

[JP2020]

Thanks for your reply

Long story...

switched them across two to the RT 24V connection, no wrench symbol now if I set the thermostat to manual (green light appears so signal is received). S30 is still there in the background though

 

[CBW]

Press the top right hand button on boiler display, what is the temp?

 

[JP2020]

Currently 54, set at 65 for both water & radiators