How to go about checking this PCB

[david74]

The only reason the voltage on the power supply didn’t alter was that the power supply is obviously well regulated and working as it should.
If you had been monitoring the current it would have been another story.

The board supplier says they need two weeks to fulfil the order. In a meantime, I still have the second replacement resistor from the pack. How to determine the capacitor specs to order? How to thwart potential overload to avoid the fireworks if I plug it in which did not require an arm and a leg in sophistication?

 

[mainline]

The board supplier says they need two weeks to fulfil the order. In a meantime, I still have the second replacement resistor from the pack. How to determine the capacitor specs to order? How to thwart potential overload to avoid the fireworks if I plug it in which did not require an arm and a leg in sophistication?

Really speaking you could do with a current limiting power supply.
a decent soldering /desolderer station.
A capacitor tester
Diode/transistor tester
A ring meter.
A circuit diagram
and knowledge and experience.
I would remove the capacitor and the transformer, replace the resistor and try again.

 

[david74]

Really speaking you could do with a current limiting power supply.
a decent soldering /desolderer station.
A capacitor tester
Diode/transistor tester
A ring meter.
A circuit diagram
and knowledge and experience.
I would remove the capacitor and the transformer, replace the resistor and try again.

Thank you, I will try that. But what do you mean by transformer? Forgive my ignorance but is not it called an ignition coil. Well it is a transformer. I hear you. I will try it without resistor first (and without transformer) to see if it opens the valve and come back to you.

Is there an AI that could be supplied with photos and come back with a diagram?

 

[david74]

The LZL-24H is a relay.

Yes I meant the ignition one.

Great. Thank you! BTW, there is a 24V 50A transformer too.

What I did now was to snip a leg of that resistor and without unsoldering the ignition one (but without connecting the spark plugs), I launched it and funny enough it not only opened a valve but it also went into intensive venting mode that it did not start before.

Should I add a video? Anyway here it is.

I did hear a clear click of the valve opening.

And I also understand that relay can potentially be used as a transformer. Or at least as an amplifier. Forgive my ignorance. If I sound daft.

I will hear for your answer before I do anything else because I have hair raised at the moment and need a 12h cooldown in any case.

 

[mainline]

Great. Thank you! BTW, there is a 24V 50A transformer too.

What I did now was to snip a leg of that resistor and without unsoldering the ignition one (but without connecting the spark plugs), I launched it and funny enough it not only opened a valve but it also went into intensive venting mode that it did not start before.

Should I add a video? Anyway here it is.
View attachment 118665

I did hear a clear click of the valve opening.

And I also understand that relay can potentially be used as a transformer. Or at least as an amplifier. Forgive my ignorance. If I sound daft.

I will hear for your answer before I do anything else because I have hair raised at the moment and need a 12h cooldown in any case.

The fault is probably going to be in the igniter circuit.
A relay is used to switch a higher current/voltage from a smaller one in this case it maybe switching the fan/valve or other circuits.
The igniter circuit will be delayed until the fan has cleared any gas and then switch gas to the pilot /ignitor until the sensor knows that the pilot is ignited.

 

[david74]

The fault is probably going to be in the igniter circuit.
A relay is used to switch a higher current/voltage from a smaller one in this case it maybe switching the fan/valve or other circuits.
The igniter circuit will be delayed until the fan has cleared any gas and then switch gas to the pilot /ignitor until the sensor knows that the pilot is ignited.

I have a plan, I will remove the transformer. Remove the igniter. See if igniter does spark. In the process, I'll have the multimeter connected to 24V to see how it behaves.

I will start with 2mm gap and go down to 0.5mm.

But that is all tomorrow if it is not busy as it should be as it has been quiet.

 

[david74]

I connected the igniter coil in reverse and it shows 1/100 reduction. It jumps between 3 and 2 volts. Which is plausible because the reverse would make it 20-30K. Which is the rated output.

Edit: I should have realised, it was 24V. I connected 240V to inputs and it blew.
Edit2: This looks pretty much like mine. ebay.co.uk/itm/156355372366

 

[Avo Mk8]

Edit2: This looks pretty much like mine. ebay.co.uk/itm/156355372366

If you look up the Anstoss ZIG2 igniters there are different versions, but either mains voltage, or 300V dc which produce 20kHz output, so I don't think they are a direct replacement.

 

[david74]

If you look up the Anstoss ZIG2 igniters there are different versions, but either mains voltage, or 300V dc which produce 20kHz output, so I don't think they are a direct replacement.

Ironically when order from HSP arrived it was a weird ZAG 1 igniter.
It has a sticker on it with the PCB part number but says Ignition generator.

I admire such elaborate scam.

Anyways, I went on eBay and bought a piezo igniter in order to be able to manually light it as long as the faulty PCB was able to open the valve.

A few moment later. Suddenly I started to recognise my PCB in Ravenheat igniter PCBs available on eBay. It has to do with my autistic brain.

I can swear I searched with the part number with no results, but here it was now for just £39.99 in Dewsbury, just 11 miles from me. So I got the lodger to take me there and here it is. It works!

I was not sure if anything in boiler itself blew the PCB so I connected the flue sensor through the Ohm meter. It jumped from 1 to 19 during ignition and it started.

And I have a warm house now. I have started a PayPal case as this HSP is not responding.

 

[picturevalve]

Ironically when order from HSP arrived it was a weird ZAG 1 igniter.
It has a sticker on it with the PCB part number but says Ignition generator.
View attachment 118762
I admire such elaborate scam.

Anyways, I went on eBay and bought a piezo igniter in order to be able to manually light it as long as the faulty PCB was able to open the valve.

A few moment later. Suddenly I started to recognise my PCB in Ravenheat igniter PCBs available on eBay. It has to do with my autistic brain.

I can swear I searched with the part number with no results, but here it was now for just £39.99 in Dewsbury, just 11 miles from me. So I got the lodger to take me there and here it is. It works!

I was not sure if anything in boiler itself blew the PCB so I connected the flue sensor through the Ohm meter. It jumped from 1 to 19 during ignition and it started.

And I have a warm house now. I have started a PayPal case as this HSP is not responding.

View attachment 118764

What was the value of the burnt resistor in the new unit?
Was it 1k or 1k5 perhaps?

 

[brianmoooore]

What startles me, is that during fireworks, the fuse did not go.

A word of caution when replacing burnt resistors in mains powered devices: Resistors that are likely to catch on fire under likely fault conditions are often special fusible resistors which are designed to combine the properties of a resistor and a fuse, and so not catch on fire (and burn your house down).
A fire caused by such a modification could possibly invalidate your insurance, if the insurance investigators managed to track down what had happened.

 

[picturevalve]

A word of caution when replacing burnt resistors in mains powered devices: Resistors that are likely to catch on fire under likely fault conditions are often special fusible resistors which are designed to combine the properties of a resistor and a fuse, and so not catch on fire (and burn your house down).
A fire caused by such a modification could possibly invalidate your insurance, if the insurance investigators managed to track down what had happened.

That’s why I queried the resistor value, the third band may originally have been red rather than brown - hard to tell the difference when it’s burnt up- but an order of magnitude difference in the resistance 1.5k instead of 150 ohm.
Unfortunately, when a design is “on-edge” these special resistors can give repeated faults, tempting some people to replace them with something “more robust”.
Having said that I don’t think this was a special, all the ones I’ve seen don’t burn up.

 

[picturevalve]

I checked the other resistors and compared the readings with the stripes and they were all a match except one where AI said it should be 33K Ohm but my tester just shows that it was 32.7 without specifying that it was in K.

The problem was that the protective coating the PCB and parts are covered in are difficult to scrape through.

I could not get any readings from the relay but the board was opening the valve so if that was what relay was supposed to do, then that is ok.

Your meter has a 3 1/2 digit display, so the max. reading on the 200k range is 199.9k, so 32.7 reading is 32.7k. You interpret the meter reading wrt the meter range selected.
On the 20k range, the max. reading is 19.99k. A reading of 0.32 on this range would mean 320 ohm so you would switch to the 2k range if you wanted more "resolution" on the reading - that 320 ohm would then turn out to be between 315 and 325 ohm, usually.
Read the manual that came with the meter.