I've had a plumber out today to fit new rads. Previously have had no probs with boiler. Now, loads of air bubbling round system. Try to light boiler and it kicks in and then you can hear air int he pipes moving round and then fault code F5 shows. I cannot find my instruction manual.

Can someone please help - we have no heating or hot water.

thanks

Jo Bourne, November 2007

Jo Bourne - November 2007, you are a legend!

Mark Donne, July 2022

yes, Hi, just wanted to say red reset button worked for me also.
Originally, water started coming out. It ended up being the filter had popped out, then it over heated, presumably because of no water in it?? Anyway when I fixed and re-preasurised, got the dreaded f5 when trying to turn on. Thought it was time to call mr. glowworm fixer, but this red re-set worked for me.

joel, January 2014

My boiler locked out on F5.I contacted the insurers ,was called back by Glow worm as they are the prefered repairers.That was on Saturday they quoted a response by the engineer for the Tuesday. After a fruitless conversation it was still going to be tuesday.What good is that to anyone.I found your advice for the F5 stat very helpfull we now have hot water and heating again.

Stuart., February 2013

The pressure dropped in the system - not sure why - have found small leak on pressure reducing valve on water tank - this could be it - F5 showing on boiler took advice regarding the little red reset button on thermistor - boiler kicked back into life can hear a bit of air moving around though -

Mike, March 2012

why dont you show the answers to peoples questions, complete waste of time !

steve, February 2012

Hi my hot water will come on and water will heat but when i put on heating it comes on but rads stay cold. F 22 and F 25 are always coming on. i have no manual for the boiler and dont have the money to call plumer. any suggestions

Thanks

james, March 2011

Just wanted to add that the red switch reset worked great for me, I think I tripped the F5 error when I turned some of my main rads off leaving only 3 of the smaller rads on, seemed to cause the overheat, lesson learned and saved me a packet on plumber fees, no doubt would have taken a few hours to sort out otherwise hehe, cheers guys, Just.

JWillis, September 2010

Not so much an answer but a ringing endorsement of Jo Bourne's answer. The magic red button top left inside did the trick. No more F5, plenty of hot water for a shower now.

Thanks for the excellent post.

Walt, August 2010

I'm just sat listening to my boiler purrrring beautifully what a feeing! Decided yesterday to take the plunge and add my first DIY radiator to my CH system. All went well, or so I thought until I tried to restart my boiler and got the dreaded F5 fault code! Found this web site this morning and took Jo's advice. Bingo!! Now sat with a glass of red wine proud as punch and very, very thankful!! Keep up the good advice its much appreciated!

Smiling Widely!, July 2010

Same problem after radiator resited.
Red button reset and everything working fine. Thanks (I could already hear the sharp intake of breath and till ring)

Chris D, June 2010

seems every one giving advise should also let people know how dangerous it is to mess with boilers.I havent seen any one advise about correct isolation of electrics or possibilities of carbon monoxide poisoning caused by people messing with things the dont understand.

BE SAFE, May 2010

Never ever, ever buy a Gloworm. I bought a 24cxi about 4 years ago, I have spent more money replacing parts and getting it fixed than it was originally worth!

Phil F, April 2010

Fantastic advice about the red switch. This is the same for the 30CXI. I drained our system to change an elbow. Refilled the system, up pops F5. The red switch did it which ws just as well.

We have a 4 month old baby and as a result, the 3 star cover from glow-worm. So what it the minimum response time from Glow worm when calling for emergency assistance on Saturday afternoon? Tuesday. This 3* cover is not worth the paper it's written on.

Boiler working fine again, house warm, baby content and looking forward to his warm bath.

Thanks again for the assistance.

Darren Kelly, February 2009

Thanks for the tip to reset the overheat thermistor. Saved a plumber's call out. Phew!

Richard, December 2008

Wes, did you get your F1 error fixed? Our boiler is a 30ci model, but also the random F1 errors from new. After several repair men said they had no idea what was wrong, all we can do is guess at causes, such as there seems to be a breeze coming through the unit - could this cause it? Also it seems to only happen on particularly cold days. Any ideas folks - I hate to leave the cats in the house for a few days (with a cat sitter) with a heating system that is playing up!

Rachel, November 2008

Hi... thanks a lot .... Jo Bourne.... the boiler is fixed and working fine now....

fubu, September 2008

hi i have f1 on my 30hxi what should i do, its been doing it from new, i have had 4 different people look at it and change different parts, 2 year later still same

wes, January 2008

Try this link. give it a few minutes. It is a slow

www.glow-wormorders.co.uk/manuals/pdf/hxi_manual.pdf

Michael, November 2007

Try this link. give it a few minutes. It is a slow

www.glow-wormorders.co.uk/manuals/pdf/hxi_manual.pdf

Michael, November 2007

We are on our second 30HXI. First one lasted 2.5 years. This one is kicking out an F1 code just short of 2 years. It is a total nightmare.

Michael, November 2007

F5 fault code ... if you've been adding rads to system or similar, then chances are you have introduced air into the boiler, which causes the thermistor to click off.

You need to take off the front panel (2 retaining screws underneath) and lift off. Then take off silver panel (remove retaining screws again). Top left hand side of innner workings of boiler is the overheat thermostat/reset switch. Two black plastic prongs sticking up with red button inbetween. Press down on red button - it should click. You have reset system.

Now restart boiler - turn central heating water temperature control dial (on LHS) to 0. Turn mains reset switch (RHS) to ON (1) position. Green light should come on and then go off. SYstem pressure should show on digital display. SHould read at least 0.7 bar.

Turn central heating dial (LHS) ON. The lighting sequence will begin, lamp will go green to show boiler has lit and you should be able to see the flame through the peep hole. Display should show system temp now rather than pressure.

Put the silver plate back on and then the front cover!

The manual can be found for 12/15/18/24/30/38hxi on the following web site: http://www.high-efficiency.info/images/hxi%20install.pdf

hope this helps

Jo Bourne, November 2007

No - it's not. I keep trying to restart, huge amounts of air bubbling in pipes, motor "whirrs" and then the F5 fault code pops up. I've found a manual on line (http://www.high-efficiency.info/images/cxi%20install.pdf) which states that the fault could also be due to "air in system with thermistor at maxium setting". This sounds more suitable (the air part!) but can you shed light on this statement. How do I get air out of the pipes near my header tank?

thanks

Jo Bourne, November 2007

dont know if there is anywhere online that you can down load
a manual
is your boiler ok now.

barry, November 2007

is there an online source anywhere? why should the boiler be overheating?? it hasn't been on all day...

Jo Bourne, November 2007

F5 is over heat stat
i can email you a manual if you like

barry, November 2007