Baxi Neta-tec works on water but intermittant on ch heating

[sinbad]

Our Boiler is a Baxi neta-tec combi boiler,installed 2011 and serviced by the same gas safe firm every year.It has not had the central heating run until recently.When this is called for the boiler goes through the motions of trying to light ,gets what i would call a soft flame and then goes out.This cycle continues until the flame failure alarm ,code 128,occurs.The reset button is pressed a few times,the boiler resets and wil light (not on the first attempt but will light)
When lit succesfully,there is a noise as the flame gets stronger(it sounds healthy).Could this be what i would call the high flame
The hot water side works fine
Parts renewd by the gas firm so are:-
Pcb board
Flame sensing electrode
Flow return sender (pt no :-T-o-d s) not sure of the part description no taken from part
Another sensor (pt no:-ontoil-6609-l105-1115 ab)not sure of the part description no taken from part
Leads to these sensord have been replaced also
The gas valve has been exchanged with another then ruled out and replaced with the original

The boiler was lit on heating via the remote control device and cut out.The remote control device was moved to a cooler room and after some time cooled down ,called for heat and the boiler lit with a healthy sounding strong noise .
The remote control was turned down to a low temp for the evening and in the morning was turned up,calling for heat but the boiler failed again with the error code 128,the reset button pressed and it eventually started.
Has any one any experiance of what could be the cause,maybe something sticking after not being used for several months
Thanks for any suggestions
regards

 

[Gasmk1]

Get baxi in to do a one off repair.

 

[AMGasServices]

I think the gas valve will probably need setting up. If it fires up and then goes off then I’m assuming when it modulates it fails as a result it knocks off.

 

[sinbad]

Get baxi in to do a one off repair.

Gasmk1,
thank you for youre reply.I have already been in touch with Baxi snd they say they would send some one and i must take out their insurance policy that will cover me for breakdowns for 12 months.They did not say what would be covered.That would be approx £350 + the cost of parts and labour so far but will bear it in mind

 

[ShaunCorbs]

Gasmk1,
thank you for youre reply.I have already been in touch with Baxi snd they say they would send some one and i must take out their insurance policy that will cover me for breakdowns for 12 months.They did not say what would be covered.That would be approx £350 + the cost of parts and labour so far but will bear it in mind

nooo they do another service which is a fixed price repair normally around the 250/270 mark

 

[sinbad]

I think the gas valve will probably need setting up. If it fires up and then goes off then I’m assuming when it modulates it fails as a result it knocks off.

AMGasServices
Thanks for youre reply.When you say set up the gas valve do you mean check the pressure.Our chap has replaced the gas valve,a straight swop for the one in use,changed them back again and said that he didnt think it was the gas valve.Although when connecting it back he plugged in an electrical connection on the gas valve and said the solenoid was noisy
Thanks all the same though

I think the gas valve will probably need setting up. If it fires up and then goes off then I’m assuming when it modulates it fails as a result it knocks off.

 

[sinbad]

nooo they do another service which is a fixed price repair normally around the 250/270 mark

Engineer,
Thanks for the info,they didnt say that on the phone.Will see what our chap says on Monday as we dont know how much it has cost so far

 

[AMGasServices]

AMGasServices
Thanks for youre reply.When you say set up the gas valve do you mean check the pressure.Our chap has replaced the gas valve,a straight swop for the one in use,changed them back again and said that he didnt think it was the gas valve.Although when connecting it back he plugged in an electrical connection on the gas valve and said the solenoid was noisy
Thanks all the same though

You can’t just swap a gas valve like for like these day it requires setting up.

I’m pretty much convinced the gas valve is causing your issue. The gas valve has three different modes I can’t remember them and they would need to be check and set up in accordance with the Manufacture Instructions.

It’s a really time consuming process eventually your issue with be sorted.

 

[sinbad]

You can’t just swap a gas valve like for like these day it requires setting up.

I’m pretty much convinced the gas valve is causing your issue. The gas valve has three different modes I can’t remember them and they would need to be check and set up in accordance with the Manufacture Instructions.

It’s a really time consuming process eventually your issue with be sorted.

Thanks for the reply
Found it in the book,combustion and calibration,it starts combustion should be *** at all 3 fan speeds,then goes on to calibration function and adjusting the co2.Is this what you mean
The trouble shooting flow chart also said to renew the heating flow /return sensor.
Thats going to be done today
Did try to past the page in but couldnt hence the short description and length of time to reply

 

[AMGasServices]

Thanks for the reply
Found it in the book,combustion and calibration,it starts combustion should be *** at all 3 fan speeds,then goes on to calibration function and adjusting the co2.Is this what you mean
The trouble shooting flow chart also said to renew the heating flow /return sensor.
Thats going to be done today
Did try to past the page in but couldnt hence the short description and length of time to reply

Yes it’s something like that but an ordinary person can’t set it up it has to be set up using a gas flue analyser.

I would get the sensors changed just yet.

I think your have practically rebuilt the boiler from inside. It would have been cheaper to get a fixed price repair from Baxi.