DIY Doctor UK DIY Forums

Hi.
I have now changed my fan unit and things were looking good, dhw and heating seemed to be working. (Vaillant ecomax 824e)
That was until I looked at the service panel display and noticed that every 15 seconds it goes from 5 (DHW demand) to 2 (purge) and then ignites again and goes to 5 after 15 seconds. It does the same for CH.
Does anyone know what causes this?There are no fault codes, just this cucle of purge, ignite every 15 seconds.
This is getting to be a pain and and expensive one at that.
Vaillant are useless as they won't speak to "non corgi" registerred people.
Why is that I wonder !!
I do not want to fork out over £200 for pcd to end up with another fault, it would probably been cheaper to throw out this POS and get a cheap combi !!!

MAYBE THE "GAS VALVE" HAS TO BE "PURGED".

GORGI TERRITORY!!!!

Without seeing the boiler, PCB would be my first thought.
You could get an engineer out to find the fault.

But how much do you spend on a boiler, what age is the boiler ?
I also have a vaillant, if I need to repair it, i'm not willing to spend much maybe around £100-£150 - because I could buy a Main Combi for £399, cheap and cheerful.

Yes, I suppose I could call out an engineer but that would cost minimum of £220 again !!
I have two friends who are corgi registerred and one did not know but said it may be pcb as I changed fan, the other told me to check th eair pressure switch but there is not one :D
I have searched the bolier and there is deffinately no air sqitch. I think it works usin hall effect sensor to determine fan rotor speed and this is fed back to pcb to control drive of fan.
So it may be that the pcb is defective.
One other thing is I notice that on the new fan, the edge connector for the fan is 180degree rotated, so I would like to thimk that this fan is correct as Vaillant gave me part number, I just hope the pics are right way round and not got the pwm and hall pins reversed!!

Why £220 ? abit steep for a callout charge, all you want is someone with fault finding experience to find the fault. I would think about £45-£60.

Then if he says it's the PCB - you don't have to get him to fit it.

Purge - is normally air in the system - maybe air trapped around sensor or in pump ?