Help - Baxi System 100 HE plus

[professorplumb]

I serviced a boiler the otherday and they client then asked me to look at their business boiler as not worked for about 6 months. She said she had a guy look at it but said wasn't sure and never seen again.

I am wishing i had done the same.

The boiler is a baxi system 100HE plus. when i arrived it would ignite and stop within 3-4 secs of lighting. It would try this a few times then go to lockout.

I said it requires a good service as the trap is blocked, seals around the combustion cover are part damaged and the HEX is full of s***te. She then told me it had not been serviced since installed about 5 years ago.

So i serviced the boiler before cleaning the Hex i noticed it was leaking so i upped the pressure and sure enough the heat exchanger was in need of replacing in which i replaced.

I now try and start the boiler and i get the stop start lighting of the burner. I cleaned the probes and that seemed to have done the trick. I checked the gas supply in and thats fine at 18.5mb. I then fired it up and it works with it being lit for about 1.5 mins the flame seems really large and the panel very hot. MI says to wait 3 mins before gas rating i'm a bit scared to leave it this long.

Can anyone give me some pointers as paid out about £300 thinking i could fix it.

Its getting to the point where i am contemplating gatting in Baxi for them to resolve.

thanks in advance

Simon
.................................................................................................
Update.

I have spoken to Baxi whom asked me to check 240v to gas valve (their was), Ohms of 4.3 (their was) not sure what the ohms things was all about. I fired the boiler up although it took a while to stay alight which may be the flame rectification probes and spark . Boiler stayed on for aprox 15 mins. temp on the flow got to about 50 degrees before tripping out. i assume it was the stat on the fan.

The flame seemed way to high as was lifting the ceramic burner plate ever so slightly. I was also getting readings of 569ppm CO from the flue test point. After it tripped out i looked at the heat exchanger and the new seals at the bottom had cooked.

I think the boiler is burning to rich resulting in high temp and melting the seals and then tripping out the fan stat.

so whats Next.

The fan sucks the gas through which is controlled via the PCB. SO is it the Gas valve, Fan or PCB ???

Simon

 

[migoplumber]

firstly, a "business" boiler would need to be serviced every year by law, it hasnt been, you've been seen the problem so remember your know legally responsible for leaving it in a safe working condition. if you have any doubts about leaving that way, cut and cap, then inform them of what you have "had" to do. strictly speaking thats against the law, but it does help you sleep at night!!

to the problem, it sounds like both you and baxi both suspect a gas valve problem. if you have checked the gas valve outlet or operating pressure and its correct then i cant see the point of checking voltage and resistance over it. i would change the gas valve as my first choice, assuming you have dismantled the burners and cleaned them. is ventilation adequate, maybe a blockage in the flue inktake pipe. dont worry about your high co at the moment, your supposed to give the flue ten miniute to get up to temp before you test, if your not letting it get that, due to worries, fix the worries first.
absolutely a combustion problem, fix that first and then worry about heat ex and other things. good luck

 

[uplandsplumb]

Hi there...

Im having a similar problem with the same boiler model...

Having realised the high limit stat sited on the side of the fan unit was breaking continuity I sought advice from baxi tech who advised changing door seals which i duly did... Then tried it again sure enough five or so minutes and it locked out again... So then i changed burner as the ceramic plate had come loose from burner (which had warped) and was lifting on high burn..
I also changed burner bottom plate as the seals were knackered and was advised that it came as a complete kit.
Ok so I fire up whilst holding breath only to find that electrode/ignition now knackered despite light clean...
Finally, today I retry and after a few minutes I can start to smell the boiler getting really hot... Then again it locks out on the high limit stat sited at fan... ok so I understand products of combustion must be pulling down ito the fan unit but how???? The flue is clear ... The heat exchanger was initially looking like it had never been cleaned although I obviously now have... Also the boiler seems to be loosing pressure quite frequently bit I can't see any signs of leakage anywhere on boiler or system as a whole..
All I can think of is to change the heat exchanger and all the seals again.
The costs are starting to go through the roof as far as the customer is concerned and there's no guarantees that this will solve the problem...

HELP...lol

I would be very grateful of any ideas etc...

 

[professorplumb]

That boiler was a pain!!! I couldn't find the problem as client was reluctant to through any more money at it. I was also reluctant to spend anymore time when it had me stumped. I put her on to baxi or bg whom came out and resolved the issue. It was a fixed fee repair and as quite a few problems they done it under that.

A loss for me but a working boiler for client. Glad to get it off my books I am very cautious now about repair and this highlight my lack of experiance on fault finding - lesson learnt.

Good luck

Simon

 

[Mbear]

I serviced a boiler the otherday and they client then asked me to look at their business boiler as not worked for about 6 months. She said she had a guy look at it but said wasn't sure and never seen again.

I am wishing i had done the same.

The boiler is a baxi system 100HE plus. when i arrived it would ignite and stop within 3-4 secs of lighting. It would try this a few times then go to lockout.

I said it requires a good service as the trap is blocked, seals around the combustion cover are part damaged and the HEX is full of s***te. She then told me it had not been serviced since installed about 5 years ago.

So i serviced the boiler before cleaning the Hex i noticed it was leaking so i upped the pressure and sure enough the heat exchanger was in need of replacing in which i replaced.

I now try and start the boiler and i get the stop start lighting of the burner. I cleaned the probes and that seemed to have done the trick. I checked the gas supply in and thats fine at 18.5mb. I then fired it up and it works with it being lit for about 1.5 mins the flame seems really large and the panel very hot. MI says to wait 3 mins before gas rating i'm a bit scared to leave it this long.

Can anyone give me some pointers as paid out about £300 thinking i could fix it.

Its getting to the point where i am contemplating gatting in Baxi for them to resolve.

thanks in advance

Simon
.................................................................................................
Update.

I have spoken to Baxi whom asked me to check 240v to gas valve (their was), Ohms of 4.3 (their was) not sure what the ohms things was all about. I fired the boiler up although it took a while to stay alight which may be the flame rectification probes and spark . Boiler stayed on for aprox 15 mins. temp on the flow got to about 50 degrees before tripping out. i assume it was the stat on the fan.

The flame seemed way to high as was lifting the ceramic burner plate ever so slightly. I was also getting readings of 569ppm CO from the flue test point. After it tripped out i looked at the heat exchanger and the new seals at the bottom had cooked.

I think the boiler is burning to rich resulting in high temp and melting the seals and then tripping out the fan stat.

so whats Next.

The fan sucks the gas through which is controlled via the PCB. SO is it the Gas valve, Fan or PCB ???

Simon

why are YOU paying for parts? its not your boiler.

cust pays for parts always upfront.

as for the boiler, if ur not sure what ohms are then i feel you shouldnt be repairing boilers. why take a job on when you are clearly out of your depth?

 

[professorplumb]

I was out of my depth and now do not undertake repair work just servicing and installs. I thought I was good enough to fix it as had fixed quite a few boilers up till then but this one. Got my fingers burnt quite literaturally now leave repairs to the experts.