Vokera Compact 29 HE won't ignite without the case cover seal removed....?

[theanalyst]

Had a but of a head scratcher this morning chaps.
Vokera 29kw compact, About 4 years old...
I've been stressing majorly trying to fix it on a callout this morning, eventually put a new APS on it even though the old one seemed fine. NO change.
The boiler fires (mostly) with the case cover off, but just fast flashing green light, fan and no ignition sequence with cover back on.

I was suspecting the fan may be the problem, is there any way to prove this beyond all doubt? I was thinking I should have removed one of the tubes from the fan manifold and see if it worked ok (pressure equalisation problem?)

cheers

I've tested power at the PCB pins as per Vokeras crappy manual and all seems ok!

http://www.ukplumbersforums.co.uk/plumbing-forum/19726-vokera-compact-25-only-works-case-3.html

 

[SafeGasInstall]

You need to come to GsR forum pal

 

[SafeGasInstall]

Wait some one will move it over

 

[Dotty]

And it shall be done!

 

[SafeGasInstall]

Is the flue clear ? Or flue run too long ?

 

[Atouchofgas]

Had one exactly like this the other day, slid fan out took out venturies and washed them out. Boiler fired first time

 

[Mike Jackson]

I had one too. Fitted new venturis as they are updated and now plastic and resist scaling. Cost about £15 for the set. Couldn't be arsed to take the old ones out and clean them to find they still wouldn't work.

 

[vern]

What Mike said, the brass ones fur up, updated Venturi kit out now

 

[lame plumber]

if they are like the plastic ferolli ones dont touch them in 3 years time!!!!!!!!!!!!!!

 

[theanalyst]

Thanks guys. Much appreciated. Will be my first port of call on monday morning! Now I remember why I don't do repairs much lol
give me back to back installs any day!!

 

[theanalyst]

As a sidenote, what if cleaning the venturi makes sod all difference?! Replace them or new fan time...?

 

[theanalyst]

Meant to add. The flue is standard length, horizontal run through single skin wall. its totally clear inside and not part of the problem.

 

[tamz]

check what restrictor ring is in

 

[theanalyst]

check what restrictor ring is in

Cheers. How?!

 

[Ermintrude]

When your finished check fga ? Co 1790ppm cap off and F off! Last repair I did was a Friday 19.30 pishing it down and custard watching ...... Ahh looks good I'll just test....... Beep beeep beep beep high co!!!! Doh. Retest and checked flue. Left running for 5 mins on full pelt .... They have a logic + now.

 

[Ermintrude]

Cheers. How?!

Look in the mi.

 

[tamz]

Its stamped on it.
Different rings for different flue lengths

 

[theanalyst]

Cheers chaps. Yes ermintrude, good idea re FGA test. Will stick one on it as soon as it's working properly.
I've basically got to fix it or I cant get paid out for the APS and time so far though lol

I'm sure it's fan related, or venturi...

the flame picture is perfect when its actually running, I would be most surprised if its PPM is over limits....

 

[vern]

Venturi, BTW DONT remove the fan completely to fit slide forward 3inch and you can get into the back nut

 

[Ermintrude]

Flame picture may look beauriful. When running with case off did flame pulse?? If so better get the ID stickers ready.

 

[theanalyst]

Flame picture may look beauriful. When running with case off did flame pulse?? If so better get the ID stickers ready.

It didn't pulse during the time I was watching it, but I will make sure on Monday!
Thanks Vern, I will remember that advice mate

 

[vern]

It didn't pulse during the time I was watching it, but I will make sure on Monday!
Thanks Vern, I will remember that advice mate

Just slacken flue clamp off, take out 3 screws on combustion hood, pull forward just enough, BTW 3rd screw is at the back center

 

[SafeGasInstall]

Check flue elbow , you don't have a hole in the inner tube

 

[mfgs]

It is pretty much guaranteed to be the venturi on this boiler, a quick clean and it will be good to go.

 

[Deleted member 32524]

MFGS spot on. Loads of vokera breakdowns are just the venturi. This sounds very like a venturi. Same as if fan and pump on and no ignition (still on green), blocked venturi, Had a high co reading on one, blocked venturi. Really common problem on these. Easy fix though. stick a small screwdriver in so you dont drop it. Never mind with the new plastic one, old ones clean up great and i have never been called back yet.

 

[Atouchofgas]

Any feed back on this?

 

[goz666]

I've had this on a vokera and it was the fan, removed it, cleaned all the vanes which had gummed up and become heavy therefore not turning at full speed. Refit and it fired instantly.

 

[vern]

Just to be clear, you cannot clean these from the front as ther are a t shape

 

[jefaz]

Not an He but on the SE vokera compacts you can't buy the venturi separate,it comes with the fan...so vokera said.

 

[theanalyst]

Thanks guys. Well, it was the venturi!!
We were going to remove the fan to clean it, and it seemed a right ballache with the condensing assembly needing disconnecting to remove the whole top half of the assembly. (and then the boiler needing isolating and draining down ... leading to possibly leaky isos etc) .

Next on the list we tried to undo the 4 screws underneath the fan (tight in above the heat exchanger). Try as we might there was no way the back two were coming out even with a small ratchet driver.

So I ended up blowing through the venturis using some ugauge tube, and then I got a small tie wrap (actually I sliced a big on in half, lengthways) and used this to clean the L shaped venturi.

it worked a treat and went right around the corner and after that I blasted them through with a bit of air again to be sure.

Bolted it back up and she fired up a treat, and ran pefectly!!! RESULT.

Not heard anything back from the custard so it's still working perfectly (they WOULD have rung back..!)

So big thanks to all those who helped out with this bugger, and hopefully this thread will help someone out in the some boat at some point
cheers

 

[mfgs]

To get the fan out to clean the venturi, you just need to unscrew the flue hood on top of the burner and slide that out with the fan attached to it. Only need to slide it out about 3-4 inches to be able to get at the venturi. No need for a drain down and no way were you ever going to get at those screws under the fan in the flue hood with it still in place.

 

[theanalyst]

To get the fan out to clean the venturi, you just need to unscrew the flue hood on top of the burner and slide that out with the fan attached to it. Only need to slide it out about 3-4 inches to be able to get at the venturi. No need for a drain down and no way were you ever going to get at those screws under the fan in the flue hood with it still in place.

Im pretty sure we tried every possible combination, probably except this lol
Vokeras instructions about fan removal were very poorly written so cheers for the heads up