Hmmm, I think I may have broken my Vaillant boiler
Help ….. in a word!
We have a Vaillant EcoPlus 825 combi boiler, 2017 vintage which has a Salus (dumb) wireless thermostat fitted. I’ve purchased a Tado Starter Kit V3+ to replace the Salus to allow for remote control etc via Homekit.
Downloaded the App (TICK). Set up the Tado bridge onto the router (TICK). Paired the Tado thermostat (TICK)
Wired in the Wireless Receiver according to the provided diagram for combi boilers as ‘Switched Live’ (seemed to correspond with the original Salus wiring - which I temporarily removed). (TICK).
[Connected the brown and blue wires to mains L/N and grey wire to 240 RT -> CH NO on receiver. Left black unconnected]
Paired the Wireless Receiver (TICK). Configured it to a Yellow LED (TICK). Did the Test Mode (TICK).
Everything works - the App talks to the thermostat which clicks the boiler on. BUT, the boiler switches on and seems to be going through its (purge??) cycle, but never actually fires up.
I tried changing the wiring to ‘Potential Free’ configuration but that didn’t actually make anythig work. In a panic (!) I disconnected everything and reconnected the Salus Kit. Horrors ….. it started to boiler up when it called for heat but still didn’t come out of purge-mode. I figured I had to fall-on-my-sword with this and rang Vaillant. Just as the call was ringing out all of a sudden 5 mins later the boiler burst into life, fired up and started to put out heat.
Has anyone got ANY clues as to what might be happening. I’m an ex-electrical engineer so I’m pretty sure I got the wiring right but I know nothing about boiler electronics.
Should say, whilst the boiler was in the purge mode, if we turned on a hot tap it fired up OK and delivered hot water.
Asked Vaillant if they would perhaps come and do an annual service for us (due anyway) and got engineer coming on Monday.
Any help/insight very much appreciated.
Regards