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Baxi combi 105HE?

I've got a 3 year old Baxi combi 105 HE and recently it has refused to fire up unless it was coaxed by resetting it a few times. a red light was flashing on the 50 degree which relates to a fan/flue fault but the fan works fine. Now it won't fire up at all. What's the matter with it?

B.Bateson, April 2008

home Fix label Heating label_important Home Heating Systems category Baxidone

replaced diaphragm as water was leaking from front microswitch(boiler was working fine eccept for drip )but now boiler heating wont wor k water works ok wats up.

DAVE H, December 2014

My baxi (2 bed flat\4 rads) is costing £15 a day in gas. Whether boiler on lowest or highest setting, a constant 10kw to 15kw an hour of gas is consumed. It is up to £105 a week to run c.h. Gas meter is new. No fault indicators are on. What could the problem be?

Richard, December 2013

Are you people extremely stupid?

It is illegal for you to be attempting repairs on any gas appliance unless you can be proved competent.

This is by formal training and registration as a GSR.

You do not know what additional checks need to be made.

YOU ARE PLACING YOUR LIVES AND THE LIVES OF YOUR FAMILIES AT RISK!

Annoyed GSR., November 2013

hi Thanks to this site i to had my 105he just trip out. so changed out the diaphragm as boiler approx 5years old,. carried out the checks and everything said pcb. but after reading some of the posts i tried blowing down the flow switch tubes. great straight on . many tanks

newham, October 2013

working on ANY gas appliance without being a competent person registered on the gas safe register is illegal, stupid and dangerous. whether it is your own appliance or not you are breaking the law. i understand times are tough and you dont want to fork out '£100's' as many have put but gas engineers have ploughed thousands and years of training to become competent and safe on your appliances. do not be a fool call an engineer!

A GAS SAFE ENGINEER!, August 2013

No hot water unless heating is on

Kegs, May 2013

seems a common problem is the bar guage is not entirely accurate - ive had the red 60 degree L.E.D. flashing when the boiler has shut down due to low pressure (below 1.5 bar...)
today - a corgi engineer said that repressurising the system to the recommended 2.5 bar was effectively only 1.5 bar. he said to pressure the system to 3.5 to 4.00 bar as this was more likely to be a more accurate pressure of 2.5 bar....the gauge reads about 1 bar out

mid-staffs gaz, April 2013

to all you diyers, gas appliances are not for the amatuers, when parts are replaced especialy thr flue assembly checks need to be carried out as to the safe operation after repair. saving a few quid could cost you your life and that of your family...is it really worth it, i think not!

gary, April 2013

hi/ the boiler comes up fault e125 which is boiler max temp exceeded possible circulation fault in wich area should i look i,e. pump rads blocked the water pressure is correct as to the book 1.5

tony, April 2013

pin not going down at back micro switch. fault low presure and pump fault. fitted new diaphram. pin moves but donot go back down.

pas, March 2013

How easy is it to replace pressure switch can I do myself

terry, January 2013

I also have to give a massive thank you to this particular thread and the people who contributed to it. My Baxi 105 HE also had red light flashing for fault with fan or flue. Took a gamble by buying part #248466 online for £22, inc. delivery, and, as advised by someone on here, there were step by step instructions in the boiler manual for taking the fan out so that the air pressure switch (#248466) could be replaced.

Did it in an hour, and viola. It worked. Boiler working as it should again, so a massive thank you. Far better to pay out £22 than £100+ to a plumber.

Bernard, September 2012

Our heating comes on different times of day including 2am, it is not thermostat I am sure it is the timer playing up, anyone else had these problems or know how to fix, no wonder our gas bill is so high! Thanks.

Kev, April 2012

nohot water at lower temp have to set at higher temp
to work heating side is fine isb it the h/w thermostat which replacing?

dennis, May 2011

I have had same 50 fault flashing on my baxi combi 105e since before xmas. engineer has serviced, changed air pressure switch yesterday and now does not even reset or start to fire up. Seems to be when temp outside is low, could it be the condensate trap or overflow blocked/frozen as this has not been mentioned to me. I think next is pcb but would like to save a few quid if only a blockage! Is it worth a try?

Nacol, January 2011

The neon indicators, N0 6-Flame failure or blocked condensate drain and N0 8 Fault on fan or flue were flashing.
The reset function would not fire the boiler.
Having checked the condensate drain was clear and worked through the Fault Finder in the manual I was convinced that the problem lie with the PCB.
I ordered a replacement from Keeptheheaton.com £105.08( Sept 2010)which arrived within 24hrs. When simply fitted boiler fired-result.

Graham, September 2010

how do I fit a honeywell CMT927 timer to my baxi 105 boiler that is already fitted with an internal timer ?

johnl, September 2010

Hi there,

I'd also like to say thank you to all who posted ref: 50 degree warning light flashing fault.

After replacing the Air pressure switch purchased from www.keeptheheaton.com (part #248466) my boiler functions exactly as it should do. I managed to replace it myself in about 45 mins so didn't have to fork out £££s for the expertise of a gas engineer.

All the best.

Ross K, August 2010

I've replaced pressure sensor & pcb but still to no avail still keep getting first 2 indicators flash And cuts out. Please help at this rate I'll end up replacing all components .

Fretting sparky, August 2010

it is illegal for any person not holding current qualifications and not being a member of gassafe to work on any gas appliance.

PLUMBING SOLUTIONS, July 2010

neon indicator no 6 flashes (no hot water,or heating)

peter, May 2010

I'd just like to add a HUGE thank you to all who posted here RE: The 50 degree warning light flashing on a baxi 105 HE.

I ordered the air pressure switch (part #248466) from http://www.keeptheheaton.com/ for just over £20 delivered (Awesome service, placed the order at 4:30pm and took delivery the next day at 11am)

It took a handy neighbour 45 mins to fit after reading the baxi manual and hey presto... Problem solved :)

Thanks again, this site is the best!!!!
Laura (Basking in the glow of her repaired boiler as the bath fills) xoxox

Laura, May 2010

how would i fit an integral time switch to my boiler -Baxi combi 105HE

jane, May 2010

i have a warning light on saying pressure low/pump fault but the pressure is at 1.5

steve, January 2010

Further update from me.

It was not the as pressure sensor venturi as originally read (mistakenly)

I have just replaced the pressure switch (part no 248466) as suggested by the poster on my baxi combi 105he and it appears to have solved the problem. Thanks to the original poster as this has saved me a few hundred quid for sure.

All I had to do was make a note of the 6 wire colours and 2 flexi tubes that attach to the fan and it took about an hour to take out and put back in.

It actually tells you in the baxi manual that came with the boiler how to do this in detail.

Chris, September 2009

Thanks for this. I have a 4 year old Baxi combi 105HE with the same fault light and the same symtons, fan works fine and resetting starts it off after several attempts

I will try this solution and see if it works. I assume you are referring to the pressure sensing venturi.

For other people reading, this is a good site for getting baxi spare part numbers and finding their location in the boiler before opening it up

http://www.partsarena.com/

you do have to install a viewer first though and I have found it works best in IE8

Chris, September 2009

Yet another update, boiler did not last long before fan/flue fault reared it's ugly head so I bought a new pressure switch £18 delivered and boiler working perfectly from the word go and still is.
Although most sites did point to pcb, I would say if the fan comes on but no ignition try the cheaper pressure switch option first as I would have saved myself £90. But now that I have a spare, sods law will dictate that the pcb will never go wrong as it only goes wrong when you don't have spare.
If in doubt get a dog

havagogaz, April 2008

Update, bought new PCB installed and nothing happened still the same no heat, so I thought maybe it really is a flue/fan fault.
The fault finding instructions supplied by baxi pointed in the direction of pressure switch which was too inaccessible to even touch but the rubber pipes did come out on top of fan tube to which with power off I gently blew down until I heard diaphragm move back and to, put pipes back on powered up all now working perfectly could be a coincidence but worth a try just in case pressure switch sticking.

havagogaz, April 2008

Hi, I also have had this problem and other sites all come up with the same conclusion and that is the PCB board needs replacing cost about £80 from keeptheheaton.com. One repairer says he carries a stock of 2 at all times as it is a very regular fault, part No. 248074 replaced with new part No. 5112380 but ask keeptheheaton for verification, happy heating

havagogaz, April 2008

my first checks would be venturi and aps.

iain, April 2008

link Click here to see other fixes for Baxi 105HE.