Baxi Solo 2 PF 50 boiler intermittently does not fire

[Pav96]

Hi Guys

We have Baxi Solo 2 PF 50 boiler. Since last 4-5 months we have this intermittent problem; when the boiler starts for central heating or water heating (we have Potterton 6200 programmer) intermittently the boiler does not fire. We switch the boiler off and on manually and it fires second time. Even when we manually operate the programmer to switch on the central heating or water heating we can see sometimes that that flame is not lit and we have to switch the boiler off and on and it works.

Please advise.

 

[Agile]

I am disappointed that you have had this problem for so long and not bothered to get it dealt with. Most people call someone when a problem arises in case it fails completely and leaves they without heat or hot water.

Presumably you have never had the boiler serviced either!

I have no idea whats wrong with your boiler as I have not inspected it. It may just be a total lack of servicing or a PCB fault which is common on your model.

Tony

 

[gas4you]

When it doesn't fire, how far does it get? Does the fan start, or is it completely dead? If completely dead try tapping the pcb or the relays on the pcb. If it then fires it will be a sticking relay and will need a new pcb

 

[Pav96]

Hi Tony

Thank you for your response. The boiler was serviced 4 months back by Baxi. I however do not have extended warranty cover. I have already got one local guy come in to check the problem. As the problem is intermittent I was not be able to replicate it when the engineer was visiting, hence asking on this forum about others experience with similar problem.

Hi Gas4you

Thank you for your time it is much appreciated.

We have two on off cycles set on the programmer. The problem is intermittent. Sometimes in the morning the central heating does not start (0500 – 0700) other times it is in the evening. Also in between when we manually set the boiler on using the programmer then also some time we can see that that flame does not come. The boiler is not completely dead the fan does start.

 

[gas4you]

Did baxi engineer clean out fan venturi and aps pipes? I have had same 'fault' on another make of boiler that this simple procedure cured.

Other than that I would try tapping pcb when not firing as previously mentioned

 

[Pav96]

I'm not sure if he did clean the mentioned items, his invoice only mentions fixed price repair and safety gas check complete.

I looked at the boiler and PCB is not accessible, can you please advise how can I can tap it when the problem occurs.

Thank you

 

[gas4you]

PCB is located in plastic box behind boiler stat. You could try tapping base of this box. If not you will have to 'reveal' pcb to tap relays.

Unless you clean fan venturi and aps pipes yourself then we will never know

 

[Pav96]

Hi Gas4you

I took the PCB out today while still connected to the power. I switched the boiler on and it did not fire. I tapped the black relay on the PCB still it did not fire. Please note that I did not hear the flint/spark click to suggest that spark is not being produced. Normally the click sound comes before the boiler fires i.e. the flame lights.

I do not know what the fan venturi and aps pipes are can you please advise and I can try cleaning them.

Regards

 

[gas4you]

The pcb will not generate the spark unless it knows the fan is running. Could still be a pcb fault?

If you remove the fan you can then clean out the venturi and other small pipes (about 6mm dia) on the fan assembly. Also disconnect the tubes on the aps and clean these. Make sure you note which tube connects to which connecor on th aps and fan unit first!

It can be a speck of dirt that you cannot even see that could upset the air pressure flow. I always blast through with my compressor.

If all this still fails then I would suspect the aps switch. Try tapping this whilst boiler is trying to fire as well

 

[Pav96]

Gas4you

Thank you for your response.

I will clean the fan venturi and aps pipes. One more thing I would like to mention is that every time that we have this problem; the boiler not firing, always with one off and on next time it works. We do not have to wait or switch the boiler on off repeatedly.

 

[gas4you]

Whilst cleaning the aps pipes check for any small splits or cracks in them, especially at the ends