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I have a Viessmann Vitodens 100. It is showing the error

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Hi, I have a Viessmann Vitodens 100. It is showing the error message F4. I have poured warm water down the condensate pipe, (1lt roughly). I then removed and cleaned the syphon attached to it, (it was full of debris and one small pipe was blocked).
The gauge is at 1.2 pressure. I’ve tried to restart it but it still gives me the same error message
What else can I do?!?
Many thanks, Silvia

You need to reset the boiler by switching power off and then on.

When the boiler starts up do you hear / see the pilot light coming on, F4 points towards no flame being detected so would focus on checking the thermalcouple / electrode is working and that gas is getting to the burner.

Since this is rather involved it is advisable to get a gas safe engineer to attend, if you would like me to recommend such an engineer please provide your postcode.

Customer: replied 4 months ago.
Can I do something before I call a plumber? Just in case, this is my postcode SW15 3RY
Thank you and kind regards

Switch the boiler off any the isolation switch and switch it back on, let me know if you see the pilot light come on or if it comes up with a F4 fault straight away Silvia.

With regard to recommendation for a local boiler engineer I would suggest BB&PS on(###) ###-####8656 or SHS on 07784 067425, they both have excellent customer feedback, and would be the next step if the boiler shows with F4 after you switch it back on, since it suggests you need to strip the boiler down to check the gas flow, flame sensor and feed into the condensation drain.

Let me know if I can be of any further assistance.

Customer: replied 4 months ago.
I did switch the power off various times since yesterday after I poured water into the condensate pipe and after I cleaned the syphon. I’m not sure how or where the pilot light should be. Can you please tell me? Thank you, Silvia

Your boiler doesnt have a hole to view the pilot flame, but shows a picture of a flame on the digital display, to the bottom left can you see a flame symbol next to a symbol of a set of vertical bars?

Customer: replied 4 months ago.
No ��
I will need to call the professionals then!
Oh dear, I really couldn’t spend any money now!
Thank you so much

This isnt an expensive part so when calling both look for the one which charges the least on hourly rate/call out

James I and other Plumbing Specialists are ready to help you
Customer: replied 4 months ago.
Thank you James