Worcester Boilers Eating PCB's

[Mitch]

I'm responsible for 8 Worcester 24i combis; RSF or Juniors (non condensing TF!) and I cant figure out why their main circuit boards just seems to go pop randomly and frequently. Last one (Junior) using a genuine Worcester PCB lasted 2 weeks! It now wont work just flashes the LED.

I'm wondering if its voltage spikes or maybe heavy handed users resetting the reset switch too hard which might have cracked the board. Or maybe even some gas valve failure effect. Its now it getting F expensive. Weirdly a frequent precursor to PCB failure is low ch system pressure. Pressure is topped up but the board is then faulty and needs replacing.

Other than that Worcester's are excellent.

Any ideas?

Thanks

Si

[geoff]

In message , Mitch writes

They do that ... keeps me in business

What do you mean by "genuine"?

Not usually

Driven from a relay

No direct link

Not had to replace any fans then ?

Yeah, my website

[Mitch]

Geoff

'Genuine' i.e. new as a posed to repaired. But will give you a call... Is it normally the same componant in the PCB that goes then? It seems an appalling reliability when compared to say car electronics or those in say a video player or computer which last for years, often obsolete before they fail. Its currently about 1 fan for every 3 PCB's changed.

Si

[Andy Cap]

As Geoff says, it keeps him, along with both the heating and insurance industry in business. Bit like cars, the more complex they are, the higher the premiums become, but the customer doesn't really notice.

Andy C

[geoff]

In message , Mitch writes

They are still genuine worcester pcbs ...

It depends what the fault is, doesn't it

I used to recommend worcester when people asked, I can't do that with a clear conscience any more

If they wanted reliability, why would they e.g. use inferior quality relays (but not cheaper) in later boards?

[Andrew Gabriel]

Perhaps they were looking on enviously at how potterton spares was raking in a significant additional revenue stream...

[Andrew Mawson]

condensing

Worcester PCB

resetting

Weirdly a

Pressure is

Because they are not, in my opinion, fit for purpose. I've had several fail in my flats, even had Worcester out themselves on one occassion.The PCB has been designed down to a price rather than up to a specification. It is actually a harsh environment for electronics high temperatures, heat cycling and probably bouts of high humidity, along with physical proding by users pressing the reset button. A far stouter design is called for for this application.

AWEM

[Skipweasel]

Dual-mass flywheels, anyone?

[Skipweasel]

The only bit of the Sirius Cybernetics Corporation to show a profit was the Complaints Department.

[N_Cook]

Research lead-free solder / PbF/RoHS/ tin-pest and solder cracks. "Euro-solder" cannot take heat and vibration like lead-tin solder could. And after the cold spell last year, and more than usual controller boards subjected to much lower than the 13 degree C critical temperature, there will be ever more of them failing this year.

[Adrian C]

Previously known as Tiscali ...

[BartC]

What is the temperature range inside the PCB enclosure? The chips used will show an operating temperature range in their spec. But if it's that much of a problem, there could be a fan to maintain a narrower range. Or the PCB could be remote and/or thermally insulated.

Not sure why there should be humidity unless the whole thing is in a bathroom.

Pressing reset shouldn't hurt anything; that's what circuits like doing! (I used to send reset pulses to circuits under test -- nothing to do with boilers -- at 20,000 times a second. Although that didn't power-down the circuit.)

It's the bits outside the PCB that might object.

You'd think that for a safety-critical application for a dangerous gas appliance, the design would be up to scratch anyway. Unless it's so safety-conscious that it shuts down and self-destructs at the slightest hint of trouble.

[Andy Cap]

I suspect the Reset button issue is to do with mechanical stress on the board, rather than any electrical consideration - still however a design issue !

Of course they *could* specify the correct components to suit the environment, but at £150 a time it's not in their interest to do so and no one with the authority cares and once you have a given boiler, you're stuffed ( unless someone's provided Geoff contact details ).

It just yet another example of 'Rip off Britain'

Andy C

[Andy Dingley]

I don't understand those. Volvo use them, Audi use them. Neither makes them, they're both outsourced from the same maker (some part of SKF, AIUI). Volvo owners don't even know they have one, they never give the slightest trouble. Talk to an Audi owner though...

[geoff]

In message , BartC writes

It really isn't a significant problem - move on

You tell that to the owners of Suprima boilers who have worn the reset switch out !

You're thinking too much

In terms of gas safety, design does tend to be robust

[Andy Dingley]

Reminds me, I must repair the number on our gatepost. It's chiselled into stonework and filled with metal. To give it a bit more shine when I restored the gate a year or two back, I re-filled it with pewter (rather than lead). In the cold snap before Christmas, it crumbled and fell out. Vive l'Empereur!

[N_Cook]

Reminds me, I must repair the number on our gatepost. It's chiselled into stonework and filled with metal. To give it a bit more shine when I restored the gate a year or two back, I re-filled it with pewter (rather than lead). In the cold snap before Christmas, it crumbled and fell out. Vive l'Empereur!

&&&&&&& When I gave this talk last year, first one , outline of talks was a gas fitter in the audience not at all concerned about now finding the reason why he was replacing far more controllers these days , out of all proportion to the normal range of electro/mechanical failures of fans/solenoids etc of previous years. Its all money in the bank for them.

There was also someone from one of the exempt industries, who must use reliable solder, they have the opposite problem. Getting genuine components, with traditional solder on them, for the reliability they need in avionics/medical items etc

[Skipweasel]

Google for volvo dual mass flywheel problems and you might change your mind.

[Bob Eager]

I think the point there was physical stress to the board due to a board- mounted reset button being pressed rather too enthusaistically...

[Andrew Gabriel]

In my Keston, when it's finished a burn cycle and the pump and fan have finally switched off, some of the warm moist air works its way back out of the heat exchanger through the air mixer inlet, and when the case is cold enough, it condenses on the inside of the case and runs down to the bottom. Fortunately, not enough to do any harm. I spent ages looking for a leak inside, and then when running it with the case off one day, I saw it do this as a damp patch appeared on the plaster wall alongside the boiler, in line with the air mixer inlet.

What I would be interested in is be a firmware update to my Keston, if such a thing exists. I've found a few bugs in it, as a result of fully monitoring and logging it for 10 years.