Many thanks for the excellent info. My flexicom had the F9 and the startup did the four noises but no pump. Apparently it always runs the pump on startup just to make sure it is working. Took the pump motor from another flexicom and plugged it into the circuit board. This one did whirr on startup so it was the pump. Changing the pump was not too difficult. You have to drop the accessory housing out of the bottom of the boiler housing then you remove the four allen key bolts. You need to drain the boiler as much as possible as water spurts out when you loosen these bolts so a bucket will have to be put under the boiler to collect this. The replacement pump motor with its impeller (these seem to be available new on ebay) is then bolted back onto the pump and the cable plugged into the PCB. A bit of a thorough dry all round and a refilling then the boiler worked perfectly. Without Dave I wouldn't have had the clue that it was the pump. A really helpful video. Thanks.

Thankyou Dave...My boiler is working again...pressure sensor was stuck...increased pressure only from 1.5bar to 1.6bar and boiler came back to life. Thumbs up from me mate.

Thank you, Dave, this saved my life!! Got home late last night to a freezing cold house. Discovered the F9 fault and while searching found you. Managed to get the pressure up and now have a lovely warm house again. Many thanks for sharing your expertise :)

Thankyou i needed this to keep my boiler going til engineer comes out .Your a lifesaver

Thank you so much - we just had a quote for nearly £600 - boiler fixed for nothing! What an amazing service posting this information.

Absolute legend! I had a SMART meter installed today and after the engineer left and I turned the boiler on it was showing F9 code. I planned to call the service company tomorrow and feared a big bill...but then I came across this video and it worked. Boiler working and hot water back on. Thanks so much Dave ☺️

Brilliant advice.. followed info.. really easy.. Boiler working fine.. Thank you so much... Steve aged 71

Dear Dave, Christmas morning and an F9 fault! Followed your instructions and the Glowworm combiner's is now working! Fantastic! And thanks!

Great video, thank you for making it. Turned out to be the pump, unplugged it and checked the resistance, it was open circuit. Glow worm now supply a new Grundfos pump which replaces the old Wilo pump. Heads not the same so had to replace the whole thing.

Thank you so much! I would have had to wait 10 days for the council to come twiddle those grey knobs!

Phew!! Thick snow and ‘feels like’ temperatures of -10 here in Norfolk today, and I wake up to a freezing house and ‘F9’ flashing on my boiler. Thank goodness for this tutorial...probably saved me a fortune in call out charges 😳 House now warming up nicely, thanks Dave!!

Thanks very much! Glow worm wanted me to rebuild my boiler, home insurance wanted to charge an excess on emergency cover and local gas fella wanted ££££ to come a look at it. Your video sorted it right out. Thanks very much.

Awesome video , it wasn’t the flow pressure switch but turned out to be the pump like you said ! Got the new one , at first it seems like you have to change the whole housing as the bolt thickness is completely different , but you can screw the OLD bolts through the new pump holes ! Happy days thank you 🙏😁

Thanks very much for the clear and concise instructions, this fixed my F9 issue but I’ll call out an engineer to give it a service, it was only done in Feb 20 as well!

Big shout out and thumbs up! Your videos saved me a fortune in engineers fees and enabled me to better understand and fix my flexicom. Pressure sensor tip was epic

Thank you very much Dave. The boiler has restarted! so grateful for the guidance.

Thanks so so much Dave! Just got back from holiday- around 2:15am and we had no hot water and all we were looking forward to was having a hot shower after all our travelling. With your help we manager to get out hot water going! Big thank you!

Boiler playing up today (Christmas Eve Eve of all times !) and Dave's first tip overcame the problem. Dave, you saved Christmas ! Thanks ! Mike.

Dave, a huge thank you for the advice. Your pressure increase tip worked first time and the boiler is now working as per normal. Even more appreciated as it's Easter Sunday and the call-outs would have been even more pricey!

Thank you David. Excellent advice. Much appreciated. I saw the F9 this morning and until I saw your video I was worried. Turning the taps until it went from 0.6 to around 1.2 worked a treat. Maybe I have to bleed the radiators but for now, I've got the hot water back. Cheers.

Amazing, saved my night. Was stressing so much and the first video I found was this one. My flat is now warm thank you Dave 👌

Thanks for this Dave, New Years Eve and my heating goes! You saved me from passing the new year in shivering in my coat. The first solution you offered fixed it for me. Thanks again.

Did exactly how Dave explained it... its working! Thanks mate

Thanks Dave. I refer to this every time I have an F9 because I always forget what I should do. Boiler working again now. 😊

Absolute 24ct legend Dave 🙌! Thanks so much for the clear, concise, excellent and very generous information. Many many thanks mate.

Dave, you are a superstar, thanks very kindly for this. Saved me from a cold shower in the morning.

Thanks Dave, saved me £100 call out fee and managed to get it working with the first suggestion!

Absolute hero, thank you so much it worked great. F9 flashing at 1.4bar raised to 1.8 and started working fine. Bled all the radiators and was some air in them so worth doing. Now at 1.5 bar and heating and hot water working!! We tried to call 3 plumbers who gave us a weeks call out as they were so busy. Thank you for making this video as was simple to fix even for a novice! Cheers!

Brilliant, thank you. Got it going and an engineer is on route. Cheers

What with all the excitement, I forgot to wish you a Happy Christmas! Have a good one!

So grateful to you for making this video, it cleared my fault straight away. I'd read my user guide and oculdn't find anything so when I found your video it was a God send

This is so useful thank you!! Got my boiler working on Xmas day (such a relief!) but now everyday I need twiddle the taps every morning to get it going 😞

Thankyou dave got home from holibobs . Your clear instructions did the trick .

Great informative video... I managed to follow all your instructions and got my boiler sorted this mornin... Many thanks!

Super stuff mate. Saved me an expensive emergency call out fee. Thanks a million.

What an amazing video, Dave. Worked first time so cancelled the emergency call I’d just booked Homeserve. Thank you!

Thanks a lot Dave just watched the video had the f9 fault, it worked first time

Thank you Chicken man. I don't know what I did but now my boiler works. Hurray! Thank you

You, my new friend are amazing. Freezing cold house and now the boiler works!

You are a legend. Thanks. Pressure top up worked a treat.

Thank you, sterling advice and avian companion.

Thanks Dave. Had continual F9 faults in the morning with my Ultracom 30 Xsi and getting more regular. Could start using your fix by adding some water. Got the BG boiler engineer who said the expansion vessel was the issue which he recharged. He also did the annual service which was long overdue to Covid. Next morning F9 again. Was reluctant to start messing about with the boiler even though I am an engineer but decided to pull the pressure sensor. As you suggested it was clogged solid with gunk. Cleaned it out, reinstalled and F9 faults no more. Thanks. If clogged pressure sensors on these boilers are such an issue why don't they inspect them as part of the annual inspections as you do?

Thank you so much you’ve saved us money and frost bitten toes 🥶👍🏻👍🏻 It worked straight away.

Worked thanks Dave, this is working in 2020 lockdown 2.0

Hi Dave - I LOVE YOU !! - Shh - don't tell Debbie! - You're a hero and have reduced my stress levels 100%. I can now have a bath!! xx

Thank you! Very clear instructions and solved the problem immediately.

Dave You are very clear and well explained for anyone to understand and being technical person I can understand the logic behind the steps explained by you.

Thanks Dave. Away from home and you just made that very simple for the wife 👍

Great video Dave it worked a treat many thanks

Worked a treat - cheers Dave

Dave doing God’s work

Great help, so helpful, followed your instructions and it worked, hot water and warmth restored, many thanks.

Worked for me thanks.. didnt know about the easy top up knobs.

Thank you so much Dave your expert and kind knowledge has provided me and my girlfriend with a warm Christmas. Kindly appreciated. 👍

Can't believe it but you fixed the issue! Thank you!

You saved my Christmas Day, thank you so much x

Thank you Dave, saved me a few Bob

spot on this vid helped me out big time , big thanks Dave

Nice one Dave . Top man. Boiler gone from 'bobbins' to 'mint'. Thanks for the info.

Thank you, the pressure tip solved my problem

Absolute legend, this sorted the problem !

God bless you Dave

Thank you so much.. Your video has really helped me today, am very grateful.

Great advise, thanks Dave, problem saved

Thanks Dave, excellent video. Fix worked as described. Love the chicken.

Just fixed it , thank you for the video ;)

Legend, all going now. Thanks man

Thank you i did what you said but it hasn’t worked so had to call engineer but thank you for your help 👋

Brilliant, despite the chicken. Wish I'd found you a few years ago!

Thanks Dave (and your chicken). F9 error fixed after watching this. Ready for the weekend.

Thanks Dave for sharing

I used to have loads of problems with F9 sensors on a Flexicom SX30. Many pressure sensors replaced but eventually found that from the first installation - the boiler internal expansion vessel had been over-pressurised. With the boiler main system depressurised, the expansion was at 1.8 Bar. The manual says it should be 0.5 Bar. Once reset to 0.5 Bar, I have never had another F9 fault. This was not a combi boiler, just a system boiler.

thanks very much for this video mate, it's sorted it out for me!

Top work dave

Thanks for this!

Thanks for posting, a great help....

God I love KZfaq Thanks for your help 👍🏻

Thank you - Problem fixed. :0)

Great video, the re-pressurising has worked on my boiler sx18 a few times in the last 5 years. When that failed I find just wiggling the flow sensor connector has helped. Today I found that wasn't enough and had to fix the connector by squeezing the pins together. As an electrician I have often found simple problems are due to poor connections, the connector on the flow switch is a cheap edge connector onto the circuit board edge of the flow switch. Any work to remove and clean or replace the switch may mask a simple issue with this connector that could present as an intermittent fault.

Thank you , solved my problem

Great clear instruction

Super star, did the job!

what a lad worked a treat 👍an was 1.4bar

Worked a treat thank you

Quality video!

Thanks for the video Dave. I've been keeping the heating and hot water going using the top-up trick for a week now, and I've got a spare sensor. How do I drain the boiler? Is it the same as draining the whole system?

You absolute legend!

Hi Dave. Our Church Manse boiler (Flexicom Glo-Worm) is showing the F09 fault even when the pressure is at 1.4bar. Is there a way to adjust the point at which it faults?

Thanks man! Lifesaver

I've done all this and it works... the hot water that it, as soon as I turn on the heating then that's when the F9 fault appears. Time to call a professional before winter hits?

You are a saviour

Legend, worked for me

Thanks very much, sorted.

Thanks mate 🙏

thanks dave fitted pressure sensor today all working now, i had a problem fitting in new part so i swapped the rubber seal and went in easy, please advise me which grease to use and do you put it in the small hole,

Hey Dave I have a glow worm flexi com 24cx I have a timer fitted to the boiler but no thermostat. My radiators have the thermostat valves on but I would like to fit a room thermostat. Is it possible to fit a room thermostat to this boiler model and if so which one would you recommend? Many thanks Peter

I have a Glow worm flexicon 24CX, the display is the same as the one in your video, and when we use the heating, for some reason the pressure showing in the display keeps going up and up slowly and never decreases. within a week, as we use the heating, the pressure showing in the display goes up to 2.7 bars. I then need to use one of the drain off valves in one of the radiators and drain some water in order to bring the pressure down to 1.0-1.2 bars. What is causing this? I'm monitoring this situation and when using just hot water in any of the taps, it doesn't make the pressure to go up and up like when using the heating.

Thanks a lot, I just fix done it :)

Thanks so much!!!👌🏽👌🏽💥😎✌🏾

Great Video