Potterton Performa 24 venturi

[didda]

Hi
First post virgin! Potterton 24 combi
Anyone had plastic venturi in fan melt 3 times.It seems to only run for 5-6 weeks before melting.
Boiler 8yrs old has been gas rated,flue restrictor removed and gas valve replaced on Pottertons tech advice. Has run without any probs proir to February this year.
I am GSR,a very large company who repair boilers have given up.

Cheers Didda

 

[diamondgas]

:welcome: didda ... What kind of flue arrangement is fitted?

 

[didda]

:welcome: didda ... What kind of flue arrangement is fitted?

Its the standard boiler elbow horizontal and straight through cavity wall less than 700mm total length

Didda

 

[diamondgas]

Could there be a restriction through the secondary heatexchanger slowing down the removal of the flue gasses, maybe allowing them to become hotter than usual? You could check the pressure diff across the venturi connected to the secondary heat ex and then temp disconnected. That'll give you a comparison that'll determine any restriction in the secondary flue after the fan! Maybe worth talking to Potterton to find out what the expected pressure diff should be

 

[Poxi]

Hi
First post virgin! Potterton 24 combi
Anyone had plastic venturi in fan melt 3 times.It seems to only run for 5-6 weeks before melting.
Boiler 8yrs old has been gas rated,flue restrictor removed and gas valve replaced on Pottertons tech advice. Has run without any probs proir to February this year.
I am GSR,a very large company who repair boilers have given up.

Cheers Didda

Burner Pressure ??
Keep Water pressure At 1.5 bar, Remerber no pump over-run on the 24 so there is a lot of latent heat after the boiler has done a Hot Water Run

 

[Anton]

I had the same problem on a Baxi Combi 80 Eco, 10 days ago (Baxi....Potterton...ring any bells yet?)
Same thing, venturi melted, and deformed. I struck lucky on this this one. There was a previously melted venturi left on the windowsill, how's that for fault finding skills? (venturi was replaced previously 6 months before by a.n.other)
Anyway, I replaced the venturi the next day. The burner flame established and everything was ok. Except for the fact that there was no demand for anything, hot water or heating, oh! and the pump had no power to it. So I had full burner on with no demand, and no pump running either.
The pcb was at fault. Why this boiler has no low water pressure sensing device fitted I don't know. The heat from the heat exchanger had travelled to the fan and deformed the venturi.

 

[didda]

Thanks everyone,pcb changed yesterday.We`ll have to wait and see

Didda

 

[Billy Bob Bob]

it will be the pcb,seen this fault before as said the burner comes on but the pump does not run

 

[SafeGasInstall]

i am sure it was you mark , who said long ago you had a same problem with sticky ap switch

 

[casaco]

Had the same problem a few weeks back, it only stopped when I changed the pcb, the fan drops out before the burner shuts down.

 

[Billy Bob Bob]

i am sure it was you mark , who said long ago you had a same problem with sticky ap switch

had one do this with a sticky aps,ariston microgenus 2 also melt there venturies if the aps fails this fault though 9 times out of ten wont be the aps on a baxi,it will be a pcb,worst still the worcester junior melts the entire aps when the pcb goes pop