Vaillant Ecotec plus 831 won't ignite no error

[Wictod]

Hi,

I have an ECOtec Plus 831 that has just stopped working..

Basically, the boiler pump starts running and the radiator sign appears with the pump running sign in the window but the boiler won't fire.

There is an initial whir of the fan as it tries to fire up but then just cycles back through the same scenario repeatedly. same for the water water, the tap sign appears and does the same thing with the fan then goes through the process again without firing up.

Anyone have any ideas what the problem is?

There are no error codes displayed and you can see (and hear) the diverter valve moving in and out with these cycles.

The system is clean and loaded with x100 & x200

Regards

 

[Agile]

Faults need diagnosing and not guessing at.

Diagnosing is done at the boiler and not on the web.

But what is the status shown as?

Tony

 

[Wictod]

Tony,

Agreed, I have an registered Vaillant engineer coming tomorrow to have a look.

There are no status codes shown on the screen expect for the radiator and pump symbol when it attempts to fire.

Regards

 

[Dean744PiN5]

pressing "i" gives you a s. code which tells you what the boiler is doing at that moment in time.

 

[Wictod]

Thanks |Dean

S.2 then S.97

It was cycling like this yesterday for about 2 hours fired up and worked all day then same thing again this morning.

 

[Dean744PiN5]

s.2 is pump running
s.97 is Water pressure sensor test, heat demands (hot water
or heating) are blocked


the boiler will probably start throwing a f.75 code soon if it hasn't already, There are several causes for this fault but it involves breaking a combustion seal on the boiler so needs to be done by an rgi (and someone familiar with the boiler and its faults)

if you press i and - together will bring up stored fault codes if there are any press + to scroll through and note them down and i again to exit.
will help give an idea of what your systems history is like.

 

[Wictod]

Appreciate the advice Dean, Vaillant boiler are coming this afternoon so hopefully will get sorted.

Had the f.75 a while back and had the two pipes with rubber hoses replaced with copper and sensor position moved to top of pipe.. all worked good for a while but now this problem.


Regards

 

[Dean744PiN5]

your welcome, report back with the findings.

 

[Wictod]

Ok Vaillant boiler man turned up this afternoon and got stuck in. Was puzzled there wan no error codes and called Vaillant.

I then told him that the boiler can me made to fire up by applying a little heat from a hair drier to the PCB (a trick I have used on other equipment that I'm familiar with). So demonstrated that to him and he said that's a new one on him and then reckoned based on that the board must be knackered.

So he got another board from a local supplier fitted it and she fired up first time.. Got him to service the boiler and all is well.

On inspection of the board 2 black capacitors (470 uf) situated on the edge of the board look to have sweated themselves.

So apart from the rather large cost of PCB i'm very happy with the work and the Vaillant guy was very professional and helpful. Got a years warranty on the parts so hopefully they won't go pop in 18 months.

Regards

 

[Mangs]

I had similar problem with ecoTech plus 630 R1 system boiler. No fault codes. Local engineer came, changed pressure sensor but that did not fix the problem. Still can't understand why he changed pressure sensor when sensor showed change of ~0.2bar when boiler pump starts running ! He said he needs to talk to Vaillant help line and went away !

I did my on investigation and saw that as soon as fan is engaged the voltage between ground and +24V cables drop to about 18V. So I guessed it is wither fan faulty or circuit board. More search on internet lead me to this page. Tried the the hair dryer trick and boiler worked. So got two new 470uF, 35V, 105C electrolytic capacitors from Maplin (total cost £0.98), replaced them and boiler work fine. Please note: I am competent with electronics/electrical.

 

[Agile]

Yes, you may be competent on electronics.

But even so a DIYer should not be opening the room sealed case of the boiler.

The two capacitors are the main smoothing caps and I think the originally fitted ones may only have been rated for 85 C. If so not a very wonderful choice of components for a long life.

I expect you would find a very high ESR on the two you removed!

Tony


PS Your local engineer does not seem very proficient at fault finding if he changed the pressure sensor when it was responding correctly!

 

[DP]

he two capacitors are the main smoothing caps and I think the originally fitted ones may only have been rated for 85 C

Care to elaborate? Main Smoothing capacitors? On a vaillant board?
TOO many questions

 

[Dan Robinson]

That will never be answered

 

[Bunnyman]

Its amazing how tony comments and as soon as a reg engineer appears he disappears

 

[Steelmasons]

Its amazing how tony comments and as soon as a reg engineer appears he disappears

Charlatan.