Glow-worm 24CXI

[bewsh]

I had a part fit job off one of the other guys at work - fit a PCB for a Glow-worm 24CXI, easy job....

I couldn't get hold of him to find out the original fault, so fitted the new PCB and then still the boiler wasn't working. Asked the customer what was the original issue, and he said that there wasn't any power from the main PCB to the interface PCB. Which is now ok, interface PCB is getting power.

So, I also noticed that the burner had the old style silicone gasket, so stripped it out and replaced with the updated graphite version with locking nuts.

Then when going to re-commission the boiler, I put it in to service mode at maximum, where it should display the fan speed, but instead it shows 05 for a second and then 00, and after a couple of minutes it started to try and ignite without success and then after a while go to fault code F13 - something to do with a dodgy connection at the main PCB. All connections ok, checked continuity through wires, all ok.

Checked voltage at the fan, across red and blue wires, getting 38vdc, where it should be 24vdc.
Checked voltage to gas valve, nothing at all.
Checked gas valve resistance, getting 54 ohms across the outer pins, should be 55 ohms, so thats ok.
Checked continuity through overheat stat.

Would you guys say that I've been supplied with a faulty PCB? They are pretty pricey, so don't want to be ordering another PCB if not required.

I know the PCB's are a bit crappy on these, I've had a couple where, I've knocked the power off to carry out safe isolation, knocked power back on and it's blown the board!

Any advise is greatly appreciated, cheers!

 

[bewsh]

Oh ye, I was late fitting it, so the Glow-worm tech team had closed.

And, I checked all the potentiometer, dip switches and comms on the interface pcb, they are all correct for the model.

 

[lame plumber]

make sure all the connector pins are still straight and you havent bent one. did you try the boiler on the old pcb and fault find it first, if not wack it on and see the fault then start and see if you needed a pcb in the first place!

 

[bewsh]

Ye, I tried putting the old PCB back in, and nothing worked at all, no display, nada!

Checked all the connections, all ok, nothing bent out of place.

Only thing I can think is the new PCB is faulty out of the box.

 

[lame plumber]

did you put a damp finger on it, been there and shorted out a new pcb straight fm the box

 

[southcoastboile]

I have had this before! Double check you have the connections up the right way on the pcb. I think 2 of them point upwards and the rest down.

if so then it is likely to be the wiring harness. Even though you have continuity from one end to the other. This had me scratching my head for ages and have had this twice now.

because I had continuity through the harness I assumed it wasn't causing the fault the first time so ended up changing the display pcb, pressure sensor and main pcb.

 

[bewsh]

Thanks for the replies guys. I have checked all connections, they are all the correct orientation.

 

[Anton]

F13 is described as main pcb fault. Was the new pcb in a sealed packet ?
I would give Glowworm technical a call from the job, before ordering a replacement board, so they can give confirmation after talking you through a few tests with your multimeter.

 

[Whyme]

I know it sounds daft but sometimes the little connectors push back out of there block slightly when reconnecting and dont make a proper connection. just a thought.

 

[bewsh]

Ye it was brand new sealed PCB.

I've made sure all connections are in place, I've even tried running the boiler with the PCB cover removed and the housing dropped down to make sure it wasn't pulling on any cables when up right.

I'll give Glow-worm a buzz shortly

 

[Aquazone]

I have had this before! Double check you have the connections up the right way on the pcb. I think 2 of them point upwards and the rest down.

if so then it is likely to be the wiring harness. Even though you have continuity from one end to the other. This had me scratching my head for ages and have had this twice now.

because I had continuity through the harness I assumed it wasn't causing the fault the first time so ended up changing the display pcb, pressure sensor and main pcb.

This!! One of the connectors at the back in the middle goes on both ways, but only works one way. J13?? Might be wrong tho.

 

[kris]

Careless delivery drivers can be a ghostly cause for recieving a faulty PCB , tossing them about in there vans as some PCBs dont have the best wrapping/protection

 

[bewsh]

Went through all connections with Glow-worm, all are correctly positioned and correct orientation.

They suspect faulty PCB also as getting too much voltage to the fan, and no voltage to the gas valve, so ordered a new one up - hopefully this will sort it.

Ye it wasn't the best packaged board, just in the anti static bag and shoved in a box, no bubble wrap or anything!

 

[kris]

Sounds like the fan relay has taken a knock, can you hear the relay click, if its sticking sometimes a gentle tap can revive if just sticking , there at the front of the board,

 

[kris]

Ignore that bewsh, i thought you said no fan soz

 

[kris]

I hate spending money on PCBs as some are crazy prices especially alphas, ive been looking at courses that will enable me to work on an fix them, ive done a couple fixes in the past with tracing dry joints and removing a resistor and soldering on a new one but id like to get right into proper circuitry, resistors , capacitors are only like 20p so i think its gonna bennift me in fault finding and electrical in general,

 

[southcoastboile]

Let us know what it was when you've Sussed it. I bet it's the harness

 

[arran197]

I've had a faulty board from glow worm before. I'm trying to remember which model it was. But it was a old one. I wanted say Swift Flow, but I'm not 100% sure.

 

[Billy Bob Bob]

glowworms are tat,aim at nearest skip,hate the heaps

 

[bewsh]

Took me a while to get back to here, been a hectic few days, didn't get in until 1am last night and back out at 8am! Some woman thought she had CO poisoning because she had a slight headache, wales&west utilities capped her gas until her boiler was serviced...

Anyway, ye it turned out to be a faulty PCB, fitted another new one and it all worked a treat!

Ye, I would love to get in to all the circuitry, kris, it would help a lot with fault finding, etc! I remember going to a breakdown before where the PCB was faulty, told the guy it was a dry joint on the board, came back with a new PCB and the boiler was all working, the guy was a gambling machine engineer or something and had removed the PCB and repaired it!