Baxi Solo3 PFL 60 Boiler constantly switching on & off.

[purley241]

I have just today received & replaced the Fan Unit on my Baxi Solo 3 PFL 60 Boiler after the original one started to make a terrible racket & final stopped Running on Saturday (right before the coldest day of the year !!) .

The Boiler fired up first time, new fan ran sweetly but now the boiler runs for a 10 seconds max & then the Pilot & main Burner light trip out & the Boiler fires up again repeating the cycle, sometimes tripping out after just a few seconds. Didnot do this before Fan failure. Rads & HW are both working though (house back to respectable 20 deg from 12 Deg this morning)
The Boiler light & fan light remain on & the fan remains running during the trip out. I checked the voltage to the fan & this is an uninterrupted 240V.
Could this be an APS issue ? I will check the continuity across the White/black connections with the Power off & system cooled down as suggested by other forums. I did trim the Flexible pipes as these seemed hard & brittle at the ends, but wondered if these could have been damaged elsewhere & if this would give the symptoms I am experiencing ? The APS was replaced 12 months ago.
The Boiler seems to run longer (magnitude of seconds) with the combustion box door loosened / removed. Could this simply be a blocked injector due to dislodging some dust when removing the fan unit or something else i.e a PCB problem ?

 

[lightning]

The Boiler seems to run longer (magnitude of seconds) with the combustion box door loosened / removed.

Leave it alone and call in a rgi ,what you are doing is dangerous.

 

[45yearsagasman]

Seconded

 

[purley241]

"What you are doing is dangerous" Guys appreciate your comments but I didnot run the Boiler with the Combustion Box Door Open for any Duration, only as a test. Replacing the Fan unit was a simple enough job for an Engineer with good mechanical / electrical knowledge & more so common sense !!

My posting was to avoid another day off work supporting an RGI with a Voyage of discovery and replacement of every part at my expense if this was likely to be down to a simple thing that could be replaced which didnot require specialist tools/skills (Pressure testers etc)

I did further investigation in these forums and found one thread that had similar symptoms with the solution of removing the Fan Outlet Restrictor, which I had removed from the old broken Fan & duly fitted to the new.
In your Experience then guys, could you possibly explain why a RGI (who fitted the Boiler in the First Place) would have fitted a Fan Outlet Restrictor to a "Left Hand Horizontal Flue" when it clearly states in the Baxi Manual that this is only Required for a "Rear Flue only up to 500mm" ?
Do you think moving this Restrictor will be "Dangerous" ?

 

[bobw1956]

If you look closely at the APS tubes you will probably see that the nearest one is kinked,(bad design on this boiler).

Change both the tubes,making sure they are not kinked, The APS rarely give problems in my experience

 

[purley241]

I checked the tubes and trimmed one that had a slight kink and retried boiler. The boiler ran a little longer before cutting out and then in again so I believe this contributed to the issue but was not the primary cause.
I took the decision to remove the fan restrictor as this should never have Been fitted in the first place as not a rear mounted flue. What a difference, no cutting in and out, boiler runs quieter, and rads are nice and hot. Begs the question, will this affect the efficiency of my boiler hopefully in a positive way?