Vaillant Boiler ecoTEC+418 - Status Code S46

[Dunbar]

Live monitor is giving me status code S46 (Comfort Protection minimum load loss of flame). Symptoms are boiler taking longer to come on and takes longer to heat rads, although it gets there in the end. Flame is lower on symbol and boiler quieter than it was.

Anyone got an idea of why the operation has changed and if I can do anything without having to get an engineer out. Thanks.

ps I have had similar problems in the recent past, but Vaillant came out and fitted a new pcb but didn't say what the problem was. I had managed to get the boiler working better by changing D0 from auto to 16-18kw. That lasted for around one week. I then changed back to auto and same happened. This is the first time I've seen S46 however.

 

[Aquarius]

First time I’ve heard of it. If it’s a loss of flame, then it seems more ignition/ignition monitoring or gas supply, which requires an engineer.

 

[Dunbar]

Time to give up on this. Vaillant engineer called today, said nothing wrong. Intelligent boiler knows when to ignite and how much flame is required. He couldn't say why it was operating one way for four years and then changed. Maybe it's like us, and we get cleverer when we reach four. Anyway, he fitted a new sensor although no error code and it's it's roaring away again like an under four year old. If it's doing that now why wasn't it doing that yesterday. Any way thanks for the comments and on other thread.

 

[Dunbar]

Just for info in case anyone gets a similar problem. Boiler still working OK, so it must have been the sensor. So, maybe there can be something wrong with that component despite it looking OK. Moreover, maybe a problem doesn't always show up when tested.

 

[Patrickb123]

Just for info in case anyone gets a similar problem. Boiler still working OK, so it must have been the sensor. So, maybe there can be something wrong with that component despite it looking OK. Moreover, maybe a problem doesn't always show up when tested.

We have a similar issue. The boiler seems to come on at random times and no one can explain why and has the S46 code when it does. We've had a plumber change the programmer but that didn't work and now Vaillant have said they're coming out to do the PCB. When energy costs are so high at the moment I'd rather avoid my boiler turning on needlessly.

 

[phillip439s]

Just for info in case anyone gets a similar problem. Boiler still working OK, so it must have been the sensor. So, maybe there can be something wrong with that component despite it looking OK. Moreover, maybe a problem doesn't always show up when tested.

Hi I know you posted this awhile ago but I'm having same issue service code S46, would you be able to tell me what sensor needed replacing? many thanks