Vokera 96E 'blocked flue' light

[GRC]

Recently had the boiler serviced, got the diaphragm that switches the hot water on and off replaced at same time.

Shortly after this, it showed the 'blocked flue' red light, so got the engineer back, and he stripped it down, cleaned a few cobwebs and dead insects out of the flue, cleaned the venturi, and put it back together. We tested it before he left, and all seemed fine.

However, it's still tripping the blocked flue light, and shutting down. It seems to do this when the heating is running, and we draw hot water. We get one go at the hot water, and when we try the hot tap after that, it runs cold.

If I switch the heating circuit off, so that the boiler is in 'hot water only' mode, we get repeated hot water as much as we want, but then switch the heating circuit back on, and it seems to trip the blocked flue light at some point. Difficult to tell exactly when, as the boiler is in grd floor garage and all taps are first floor and above

Can anyone offer any useful suggestions as to where the trouble may lie? The engineer mumbled something at the last visit about it possibly being the control board, and I'm on the verge of ordering one. Is unplugging the board and replacing with a new one a reasonable DIY task, or should I get the engineer back to do it?

 

[Boilerman2]

Not a DIY task as many PCB's have to set up and ALL boards have to be tested to prove safety

Personally I prefer to supply parts rather than have clients getting them directly as it easy to get the wrong parts

 

[Agile]

I always recommend people to let an engineer diagnose and buy parts.

So if he makes a mistake then you dont have to pay for parts which are not required.

If the engineer is so unconfident that he will not do that then change your engineer for a normal one!

Tony

 

[GRC]

No, didn't say the engineer was unconfident, merely that I was thinking of buying it meself ...

 

[GRC]

Do I take it the unspoken view then is that it might be the board at fault?

 

[Agile]

Just why do you want to buy it?

If you do then if its not required then you are stuck with it ! What benefit is that to you?

We have not seen your boiler and have no idea of whats causing the problem.

It MIGHT be the PCB but it MIGHT not be the PCB !

Tony

 

[Agile]

Recently had the boiler serviced, got the diaphragm that switches the hot water on and off replaced at same time.

Shortly after this, it showed the 'blocked flue' red light, so got the engineer back, and he stripped it down, cleaned a few cobwebs and dead insects out of the flue, cleaned the venturi, and put it back together. We tested it before he left, and all seemed fine.

One wonders what kind of service he did on the first visit !

Based on that performance I would doubt that he could diagnose much at all !

 

[GRC]

Recently had the boiler serviced, got the diaphragm that switches the hot water on and off replaced at same time.

Shortly after this, it showed the 'blocked flue' red light, so got the engineer back, and he stripped it down, cleaned a few cobwebs and dead insects out of the flue, cleaned the venturi, and put it back together. We tested it before he left, and all seemed fine.

One wonders what kind of service he did on the first visit !

Based on that performance I would doubt that he could diagnose much at all !

Is it part of the maker's service schedule to clean the flue and venturi?

The reason I mention a 'few' cobwebs is that both he and I weren't of the opinion it was actually blocked by them.

 

[GRC]

Just why do you want to buy it?

If you do then if its not required then you are stuck with it ! What benefit is that to you?

We have not seen your boiler and have no idea of whats causing the problem.

It MIGHT be the PCB but it MIGHT not be the PCB !

Tony

I haven't decided if I am going to yet. I was hoping to get some guidance as to what might be causing it other than the board. Do the symptoms suggest to people here that the board is the likely suspect, or do they say to someone "Ah! That happened to me X years ago and it was Y that was the faulty bit" (and Y wasn't the board)

Yes, I know you haven't seen my boiler, but I'm looking for some reasonably educated deduction and hypotheses if anyone is prepared to participate.... i.e. if the blocked flue light comes on, and the flue isn't blocked, what else could be causing it other than the board?

What senses the blockage or otherwise? Is this component known for going faulty, or is it usually reliable? etc etc

 

[ianmcd]

It is extremely easy for a qualified and experienced engineer to rule out a flue or venturi fault on this boiler and repair accordingly, yes it is possibly the PCB but they are expensive and can not be returned if not required, unfortunately we cant advise you how to test as it is combustion related but ask your engineer to join the CC on here and he will receive all the advice needed free of charge, a fair few of us experienced with this boiler on there

 

[DP]

GRC wrote

Recently had the boiler serviced

If the boiler had been serviced, he would not be cleaning the venturi or removing dead bodies on the rebound

I think what you got was a repair and operational check and a kid on service.

If the boiler is malfunctioning all the time, your engineer can not be very good if he has to assume what might be wrong

 

[ianmcd]

GRC wrote

Recently had the boiler serviced

If the boiler had been serviced, he would not be cleaning the venturi or removing dead bodies on the rebound

I think what you got was a repair and operational check and a kid on service.

If the boiler is malfunctioning all the time, your engineer can not be very good if he has to assume what might be wrong

Its highly possible that the OP did indeed pay for a boiler service in good faith, but from personal experience I would say probably only about 10% of engineers in my area would actually clean the venturi, most I know think that you can merely blow down the tube, take your point also that it was probably behaving like this pre service hence the call to service it, if anyone calls me asking for a service I deliberately delay the job for at least a few weeks and if they call again in that time you know there is actually a fault that they expect you to miraculously find when servicing it

 

[Boilerman2]

Had just such a job this week, an oil boiler needing a "Service" we had not been to site for 2 years, we booked it for three weeks time, then on Saturday morning (cold day) we get an emergency call-out "it's booked in for a service with you but it has now stopped working" - I go out and replace a failed boiler thermostat - client rings on Monday to CANCEL the Service visit!!