Ecotec ignition failure f28

[SlimD]

Hi guys,
I'm after some advice from the more experienced gas guys.
I've been GasSafe for just over a year - qualified via an intensive course (which I know some of you guys have a downer on) after redundancy. I make no claims of understanding everything about boilers as a lot comes with experience and I'm intending to get on a boiler fault finding course to try and improve my knowledge but there's only so much you can do at once.
I have been to a Vaillant ecotec 824 today which is getting an f28 fault code. Gas supply is fine but ignition comes and goes with a fair bit of banging from burner chamber. I'm suspecting the gas valve but would appreciate any assistance anyone can give. Thanks in advance.
I've taken a video on my phone of the boiler trying to ignite but site won't support the file extension.

 

[Harvest Fields]

Hello mate. This post needs to be move to the gas safe only area before we can discuss anymore.
@ShaunCorbs @Lou

 

[ShaunCorbs]

Sorted

And op try and upload it to a file site like photobucket etc

 

[SlimD]

Hello mate. This post needs to be move to the gas safe only area before we can discuss anymore.
@ShaunCorbs @Lou

Sorry not sure how you do that when posting. I do struggle with posting on this site tbh

 

[Chalked]

F28 can be lots of things.
Ionisation probe.
Ht lead
Blocked pump
Innefective pump.
Gas valve.
Pcb.
Blocked hex.
Frozen condensate

And others. I know you learning. But instead of guessing. Learn how to use a multimeter and fault find using the manufacturer flow chart.

Start with the obvious. Has the boiler being regularly serviced. If not ,it's probably ionisation, blocked burner.
Service th boiler and Follow MI and you can't go wrong. ( have you got a fga?

After that, you need to use your multimeter to diagnose further.

 

[SlimD]

Dropbox - Video 13-12-2017, 16 58 47.mov

Hoping this will work. Link to the video.

 

[ShaunCorbs]

Sounds like resistance in the flue / chamber

 

[SlimD]

F28 can be lots of things.
Ionisation probe.
Ht lead
Blocked pump
Innefective pump.
Gas valve.
Pcb.
Blocked hex.
Frozen condensate

And others. I know you learning. But instead of guessing. Learn how to use a multimeter and fault find using the manufacturer flow chart.

Start with the obvious. Has the boiler being regularly serviced. If not ,it's probably ionisation, blocked burner.
Service th boiler and Follow MI and you can't go wrong. ( have you got a fga?

After that, you need to use your multimeter to diagnose further.

Thanks Chalked. Yes got an analyser. I have a Multimeter but it is something I need to master. Using them is something that's covered on the faultfinding course I mentioned earlier.

 

[Chalked]

Take out burner. And have a look inside. New gasket will be needed.
Check flue in entirety.

 

[Harvest Fields]

Also check gas pressures at meter and boiler. I had a Vaillant the other day running on and off on 6 mbar. Was making all kinds of random noises.

 

[Chalked]

Looking closer at your video. Looks like the snorkel is trying to vacuum itself!
Have you tried taking it off the inlet? Could have collapsed inside.

 

[SlimD]

Looking closer at your video. Looks like the snorkel is trying to vacuum itself!
Have you tried taking it off the inlet? Could have collapsed inside.

Yes I took the snorkel off, made no difference

 

[SlimD]

Also check gas pressures at meter and boiler. I had a Vaillant the other day running on and off on 6 mbar. Was making all kinds of random noises.

Gas inlet pressure was 22mbar

 

[Sharp Point]

Is that grinding sort of noise from the fan?

 

[SlimD]

Is that grinding sort of noise from the fan?

No the fan runs fine that noise is coming from the burner chamber

 

[Harvest Fields]

What about working pressure? Is the boiler still Under warranty?

 

[Last Plumber]

No the fan runs fine that noise is coming from the burner chamber

Looks like a chattering solenoid to me!
Have you checked the coil resistances and the voltages to the valve?

 

[Harvest Fields]

does look like a gas issue to me to. Ever not enough from the meter or the gas valve

 

[Last Plumber]

does look like a gas issue to me to. Ever not enough from the meter or the gas valve

It does. If it was just explosive ignition and an F28 it would most likely be the electrode (gap probably). This does light straight away though doesn't it, then it seems erratic as if the valve is opening and closing. Could be a loose connection, Faulty solenoid, Board, etc. Hard to tell off video.

 

[SlimD]

I did also get an f29 come up on one occasion, hence my thoughts it was the gas valve