Worcester 240

[IMNOTAPLUMBER]

Hi there,
I have a Worcester 240 Combi Boiler, that although is working OK for C/H and H/W, after a period of time running, it starts 'clicking'. It's the same click that it makes when the temp. drops and it fires up again, but it can click 5,6,7 times in rapid succession. It does fire up OK, but can be annoying that it makes this sound all the time.
Does anyone have a suggestion as to what could be causing it?

Cheers

 

[meldrew's_mate]

Sounds like it needs a good service, paying particular attention to electrode gaps and minimum burner pressure. If the flame is too low the detection circuit may see it as "absent" and retry the ignition sequence.

 

[IMNOTAPLUMBER]

Service booked for January, (too little, too late by the sounds! ).

Is there something that can be done prior to the service?

Thanks for the reply.

 

[IMNOTAPLUMBER]

The boiler has totally stopped now. The clicking has stopped, but so has the C/H and H/W. The pump still works but seems to be just pumping cold water!
Does this indicate that the gas valve has broken?

Any advice would be gratefully received.

Thanks

 

[tomy]

in a word no because if the gas valve had gone then it would still do the ignition sequence even though there was no gas , more likely air pressure switch or circuit board

 

[IMNOTAPLUMBER]

Good news (ish).
After pressing the Reset Button, we now have C/H & H/W again. It obviously cut out due to overheating. The clicking sound is back and sounds like it is coming from the Gas Valve. Is this the Sequence Board causing problems or the Gas Valve itself? Going on what Tomy said, I guess it's the board.

Can anybody hazard a guess at the faulty part, more to the point, the cost to replace it.

Great forum, it's good to get expert opinions.

 

[IMNOTAPLUMBER]

OK, after having three opinions from experienced plumbers / engineers, all who have said it sounds like the gas valve is faulty, I have had the gas valve replaced and guess what, it is still clicking!!

Anybody want to buy a second hand gas valve?!?

However, after standing there with the engineer who came to fit the gas valve and watching and listening to the problem with the front off the boiler, the clicking is obviously coming from a relay on the main board, two questions here;

Is the relay itself replacable?
If not, what sort of price would you expect to pay for a new board?

Any answers will be gratefully received.

Thanks

 

[compheat]

No you cant just replace the relay.(there not that daft) and worcester PCB's are not expensive compared to other make's

 

[Paul Barker]

Although trhe clicking comes from the relay it isn't necessarily the relay that is starting the process which starts it clicking. There may be another fault on the board.

I had this problem with a 240 bought a new pcb for the client and it did it again soon after. Someone here said at that time that if water gets onto the pcb this type of thing happens. The pcb is liable to water damage due to where it is placed the age of these boilers and the typical scenario of leaky hydraulics above the pcb. I seem to remember one of the brass pathways between the diverter valve and the good old cyclindrical secondary heat exchanger has an o ring seal in it, that's a suspect. Also the nut connections at the cylindrical heat exchanger are suspect.

I would certainly not have changed the gas valve, and the guy who did so should not have charged you for the labour or for the part, he should have kept the part and put it down to experience.

You could dry the pocb and make sure there are no leaks, if it still clicks a new pcb might work but not being a Worcester specialist (I only see one or two of these in a blue moon, most of the older combis round here are Vokeras) don't take my word for it. Mosty of all make sure there are no leaks.