Potterton Netaheat 10-16 electronic

[plumb_know]

Hi everyone not long gas safe and would like a more experienced opinion on scenario below i have tried to give as much detail as possible as know it is hard to give advise over the internet. (bit of an essay sorry)

Called to Potterton Netaheat 10-16 electronic and was told it would come on and fire up for 5-6mins and then go off. went to job and typically it was working fine for 15mins and just as i was about to walk out the door customer turns room stat down boiler cuts out and then does not re-light when room stat turner back up.

I then turn boiler off and on and same happens boiler goes through sequence and pilot comes on but burner does not. i tap gently the air pressure switch, hear click and all fires up working fine.

turn demand off for 1 min, call for demand again and it does the same, pilot on but not burner, tap again and jumps into life.

Take PCB off so not attached to boiler casing but still connected to wiring, do same but this time tap on air switch does nothing. then tap PCB gently and again does not spark into life.

Start using multi meter to take voltage readings etc trying to trace, but this was a pain as boiler would suddenly start working so had to keep doing sequence to get fault to occur.

managed to trace 240 going through thermostat & to fan, fan spins & also got 70 ohms on fan so suggest this is good. whilst doing this i had 2 glass 1A fast blow fuses go which i put down to me prodding with the multi meter, but after putting the fan leads back on it kept blowing the fuses immediately on switching power back on to boiler. i checked leads were on properly and right way round but had to stop fault finding as blew 3 fuses and i ran out of fuses.

I have put it down to faulty PCB and have ordered a new one but concerned i may be wrong and parts are costly and dont want to damage the new PCB.

I have bought more fuses and would like to know what some more experienced engineers think on the scenario and what you would advise checking on return visit prior to fitting new PCB?

Advise appreciated

 

[Harvest Fields]

Be careful on some of these as some have asbestos inside.

 

[plumb_know]

Thanks Harvest, how can i tell if this one does? is it the gaskets that are asbestos?

They are going to get a new boiler in the summer but just want this one to keep going till then as they dont have the funds at the moment to get it replaced

 

[Harvest Fields]

Google ASBESTOS in boilers and yes normally gaskets. You will probably need the serial number of the boiler also. I’m sure I have a link somewhere.

 

[Harvest Fields]

http://www.hse.gov.uk/gas/landlords/070612-gas-asbestos-materials.pdf

Try this.

 

[plumb_know]

Thanks had read through, saids insulation & gaskets. will call glowworm if i need to disturb any tomorrow

 

[Harvest Fields]

I wouldn’t take the case off myself

 

[Vee]

Shouldn't need to disturb for PCB.

 

[Vee]

Rather would advise customer to replace it as on borrowed time. Minimum of 25 years old.

 

[Chuck]

Start using multi meter to take voltage readings etc trying to trace, but this was a pain as boiler would suddenly start working so had to keep doing sequence to get fault to occur. ... stop fault finding as blew 3 fuses and i ran out of fuses.

[...]

Advise appreciated

You don't appear to have the skills needed for 'live working' on this (or any) boiler so you should stop doing it.

Also, this is a topic that should not, IMO, be being discussed outside the closed GSR forum.

 

[Harvest Fields]

@ShaunCorbs not sure we are giving much away here mate but does this need to be moved?

 

[ShaunCorbs]

Nope he is gas safe so that's why I've allowed it for now (pre update he was gsr on here but for some reason it's gone waywood)

 

[Gasmk1]

isnt the potterton netaheat boiler positive pressure so if you remove case check seals

 

[Harvest Fields]

Nope he is gas safe so that's why I've allowed it for now (pre update he was gsr on here but for some reason it's gone waywood)

Thought so but just checking

 

[ShaunCorbs]

isnt the potterton netaheat boiler positive pressure so if you remove case check seals

Was thinking that but can't find my list of pp boilers atm

 

[Last Plumber]

Was thinking that but can't find my list of pp boilers atm

It is yes.

isnt the potterton netaheat boiler positive pressure so if you remove case check seals

 

[Last Plumber]

Can you hear the spark?
Does it stop once the pilot is alight?

Is the pilot strong enough?

 

[plumb_know]

Hi thanks for comments, i am GSR but only been for few months and have attended boiler fault finding course which was good but was bit too much info to take in all at once. ideally i would love to work alongside a gas engineer for a year but have 3 children to support & business to run so have to pick it up fault finding as i go, hence why i am trying to research as much as i can. i have had to fund my gas myself as did not get put through it when i was doing my plumbing NVQ's 7 years ago, so have only got my portfolio for experience and fault finding was not really part of it.

in response to vee customer will be replacing boiler & system but say they dont have funds right now so want it repaired till summer when they believe they will have funds to do it.

yes boiler is positive, i will do match test on seals when (if) i get it up and running again & gas rate, flue analysis swell.

pilot seems fine comes on just doesn't ignite. could here fan going and pilot kept sparking every second along with corresponding spark on PCB.

Why would the boiler come to life when pcb/air pressure switch tapped? also why would taking leads off fan and putting them back on cause fuses to keep blowing?

your knowledge is much appreciated.

 

[Last Plumber]

Hi thanks for comments, i am GSR but only been for few months and have attended boiler fault finding course which was good but was bit too much info to take in all at once. ideally i would love to work alongside a gas engineer for a year but have 3 children to support & business to run so have to pick it up fault finding as i go, hence why i am trying to research as much as i can. i have had to fund my gas myself as did not get put through it when i was doing my plumbing NVQ's 7 years ago, so have only got my portfolio for experience and fault finding was not really part of it.

in response to vee customer will be replacing boiler & system but say they dont have funds right now so want it repaired till summer when they believe they will have funds to do it.

yes boiler is positive, i will do match test on seals when (if) i get it up and running again & gas rate, flue analysis swell.

pilot seems fine comes on just doesn't ignite. could here fan going and pilot kept sparking every second along with corresponding spark on PCB.

Why would the boiler come to life when pcb/air pressure switch tapped? also why would taking leads off fan and putting them back on cause fuses to keep blowing?

your knowledge is much appreciated.

I am not getting what you mean. Does the pilot light?
If it does, can you still hear sparking?
If it doesn’t, is there Gas at the pilot burner?
Is the spark hot enough?

 

[plumb_know]

Pilot lights and has flame, fan runs but burner does not ignite.

But whilst pilot is alight is continues to try sparkings but if you tap boiler near pcb/air switch as a they are mounted behind each other hear a click which presume is air switch making and burner lights and boiler operates fine till demand is lost then burner won't relight when demand is called for again.

 

[Last Plumber]

Pilot lights and has flame, fan runs but burner does not ignite.

But whilst pilot is alight is continues to try sparkings but if you tap boiler near pcb/air switch as a they are mounted behind each other hear a click which presume is air switch making and burner lights and boiler operates fine till demand is lost then burner won't relight when demand is called for again.

If the spark carries on after the pilot is lit, then there is a problem with flame recognition. If tapping the board causes the main burner to light, then I personally would suspect a dry joint or loose joint, even a faulty PCB component. I presume you've checked the obvious things like the connection of the HT to the board and the condition of the electrode, Polarity, earthing etc?

 

[Vee]

It could also be a faulty air pressure switch or blocked venturi. To check it would need the micro switch bridged with a piece of wire.

 

[plumb_know]

Hi Everyone,

Thanks for all the help, went back this morning and was PCB put new one in and all working fine now. checked seals not leaking on boiler also.

appreciate all the help