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Potterton Profile Problem

In article , John Stumbles writes

Those Molex connectors are notorious for developing dry joints. I came across literally hundreds when I was working in monitor repair.

Reply to
Mike Tomlinson
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In message , Mike Tomlinson writes

I spend my life telling people about cracked joints

They're not dry joints, are they ?

Reply to
geoff

In message , geoff writes

Hmm..

I think electronics industry speak (of about 40 years ago) was that solder *wet* the copper track in forming a sound joint. Hence any failed solder joint was referred to as *dry*.

The Potterton profile that you and others kindly helped me fix 2 years back had two *dry* joints where the mains connector is soldered to the circuit board. As was pointed out at the time, a magnifying glass is essential to spot this fault.

regards

Reply to
Tim Lamb

In message , Tim Lamb writes

No hence about it

Yes, a dry joint is one where the solder has not wet the metal

That's completely different to one where the solder has actually cracked

Reply to
geoff

Update.

First I changed the pressure switch - problem remains.

So I changed the pcb. In doing so I noticed the connection from ignition lead to pcb connection was slack so fitted new ignition lead as well but the problem still remains.

So now on the horns of a delemma. Change the gas valve on the basis that it is now the obvious candidate or investigate further first to see if I can eliminate for sure the whole fan/pressure switch area.

Or just wait till the boiler finally expires and fit a replacement boiler.

Must say I am impressed with the speed with which the repacement pcb arrived. It was after 3pm yesterday when I phoned Geoff but City Link delivered it at 9.05am today. Doesn't look as if I will be using them for the return though. Can't get their services page to load.

Reply to
Roger

I guess it depends on how valuable your time is. At the risk of showing my ignorance can you not either test the output from the PCB to the valve to see if it's stable and/or test the valve in place with a reliable power supply?

Reply to
adder1969

The message from adder1969 contains these words:

Being retired my time doesn't have much value although I have had to break off from digging out a blocked field drain to fit the pcb and d/w the follow-up. However when it comes to messing with 240 volts I am rather cautious. Holding the probes of a meter will watching both flame and meter is about my limit. I am considering wiring neons across the relevant connections but not having any piggy-back connectors any such wiring would be rather insecure and so would I be.

The supply to the gas valve broadly matches whether the valve is on or off but I cannot be sure whether the valve failing triggers the switch off or whether the switch off is in response to another factor. Geoff thinks it might be the fan but all it would take is a leak in the pipework twixt fan and pressure switch.

One of the puzzling (to me) factors is that the problem usually clears after a period. My past experience with a failing fan was that much the reverse was the case with the boiler dying after a period in operation rather than problems mainly at start-up.

Reply to
Roger

I'm still not convinced that pilot flame stays in the electrode. There is an alternative connector for the gas valve which allows the pilot only (IIRC) to operate and also for the pcb to be swung down. This allows more involved live testing.

Reply to
Ed Sirett

The message from Ed Sirett contains these words:

The destructions mention this only in the commissioning section and specifically say "Gas will flow to the pilot only. It will not be ignited as the ignition system is de-energised."

As I mentioned in a previous post I managed to get the pilot to light by touching the detached main gas valve lead to the terminal until it fired and then removing it again. Pilot remained lit. I only let this carry on for as long as it took to establish that the pilot flame did what it said it should do in the book. Perhaps I should have left it on for an extended period to see if it went out although I am still not sure what that would have told me. Under fault conditions sometime the pilot goes out and sometimes it doesn't and sometimes I could see it sparking even though it stayed alight and sometimes I didn't see sparking. (There is an outside possibility that I have been misled but a very rapid relight).

Reply to
Roger

If it's sparking then the PCB 'thinks' the pilot has gone out even though it hasn't actually gone out.

1) Earth OK and polarity OK. 2) electrode in the pilot flame 3) ignition lead. 4) pcb.

3 and 4 have been checked /replaced. IIRC you checked 1 yonks ago.

That leaves 2. Maybe the pilot flame is too small? So maybe the pilot injector needs cleaning.

Reply to
Ed Sirett

The message from Ed Sirett contains these words:

The pilot flame looked alright when I finally got to see it for more than an instant but by then I had already dismantled and cleaned the pilot assembly although it didn't look to me as as though it needed cleaning.

Reply to
Roger

Er, have you checked the flexi pipes to the APS? They can split and leak intermittently, which might cause the symptoms you're seeing.

Reply to
John Stumbles

The message from John Stumbles contains these words:

They look OK but were too short for me to (as advised by John) trim the ends back. I had hoped the pressure switch might have come complete with pipes as I don't have a part number for the pipes. Given the hot environment I presume any old pipe won't do as a substitute.

The metal intermediate pipe is largely concealed so I can't check that accept by doing a leak test. When I get round to buying a manometer I can use that to check the integrity of the pipes.

Reply to
Roger

Is the electrode nicely in the flame and not shorting out anywhere?

Reply to
Ed Sirett

The message from Ed Sirett contains these words:

Was when I got a good look and the ignition lead is new so the should be no problem there.

I have just had a computer glitch that kept me off the internet. It may well return so if I don't respond to a future message it may be that I have been prevented from reading it. IOf something got at my computer once it could easily do it again.

(Had to restore to yesterday (first restore I have ever had to do) and McAfee is doing its nut. Signature file more than 30 days old and some parts missing - reinstall required and I haven't a clue where the original disk is. Oh well, initial info was apparently wrong as it now says protection restored and UTD.)

Reply to
Roger

You can buy silicone pipe for this at HRPC (Parts Center), and probably other places. Quite handy for rescuing ignition leads whose insulation is breaking down to chassis if you haven't got a suitable replacement lead.

Reply to
John Stumbles

The message from John Stumbles contains these words:

The reason I haven't posted any more on this subject is because I haven't been doing any further investigation since fitting the ignition module. Partly that is because I have been taking advantage of the unseasonal weather but mostly because the only time I have seen (or heard) the boiler malfunction since I fitted the new module was on start-up after said fitting. It might just be coincidence but the wind has dropped since then.

Reply to
Roger

Oh well the problem is back. For those who perhaps can't recall the earlier thread the problem is intermittent running with periods typically of about 10 seconds firing followed by a brief shut-down, particularly on start-up but also at other times. Pressure switch, ignition lead and ignition module have been changed and the pilot jet, pilot flame and spark gap checked.

Since changing the ignition module there was only one brief period during which the boiler misbehaved. Since then the weather has been calm and the problem not noticeable. This afternoon the wind got up and the problem returned. I must get my finger out and get some replacement tubing as suggested earlier in the thread as the problem surely must be in the pressure sensing area.

Reply to
Roger

In message , Roger writes

So - no wind, no problem

bit of a breeze and the bugger drops out

?

email me some photos esp. of the flue outside, I'll see if John can shine some light on the problem

Reply to
geoff

The message from geoff contains these words:

Bit more than a bit of a breeze. My wind gauge only updates every few minutes but the last few times I have looked it has been circa 20 mph and it certainly sounds worse than that. (I think I need a new weather station, wind and rain are the only sensors left working and I don't trust either of them).

Thanks. Will do when it is light. It is not an ideal placement being close to the corner on the windy (West) of the house.

If you want an aerial view and have the updated version of Google Earth stick Marley, England in the box and it will take you here. :-)

Reply to
Roger

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