Safety Lockout
- Thread starter Penster
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You'll see from previous topics and threads that I've had exactly the same problem - everyone says the venturi etc etc but that and everything else seemed fine. So, following Halstead's advice and my engineer's advice (and I have to say mentioned by Tony Glazier aka Agile on this and other forums) the PCB was replaced. Works a treat now. They are £149 from Halstead. Any Corgi guy can fix it in 10 mins.
So, go for the PCB!
So, go for the PCB!
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The point is Coxo that the PCB on mine was changed twice - without any change in the condition. One you buy the PCB you can't take it back. So my advice is check everything else - then go for the PCB.
As Sherlock Holmes used to say, "Eliminate the possible (electrodes, diaphragms, flowswitches, relays etc) then whatever remains, however improbable, must be the truth".
If it were me looking for a fault I'd remove the PCB and look under a magnifier looking for cracks on the PCB track and dry joints. They may be opening as the unit warms up. I often cure alarm panel PCBs this way so I don't see why a boiler PCB should be any different.
joe
As Sherlock Holmes used to say, "Eliminate the possible (electrodes, diaphragms, flowswitches, relays etc) then whatever remains, however improbable, must be the truth".
If it were me looking for a fault I'd remove the PCB and look under a magnifier looking for cracks on the PCB track and dry joints. They may be opening as the unit warms up. I often cure alarm panel PCBs this way so I don't see why a boiler PCB should be any different.
joe
Sometimes these long sagas are a strain for my old brain to read so I've not kept up with this one, but
why hasn't anyone checked the filter in the gas inlet
unless I missed it of course
. These can easily become blocked, not just by small bits of muck in the gas but also large bits of green coming off the inside of the pipe where the installer used the wrong flux. A blockage here can take the pressure down to nothing.
Please tell me I'm wrong and someone looked at it? Usually it means taking either a piece of pipe in the boiler, or the gas valve, out.
As said on the first page, the pcb's are weak points, they crack through the middle so flexing them by pressing on the control panel knobs can show the problem. They are solderable, though that's a dubious thing to do on a board, with safety aspects etc, and the rrp is £224 + vat on the partscenter list.
On this boiler, I'd now use a beeping continuity tester and check all the switches and bits of wiring loom I could. Sometimes poor crimping of the end of a wire breaks the conductors inside,or the insulation-displacement metal spikey bits on connectors miss, and brush the edge of the conductor inside. Freezing spray is commonly used by electronic engineers because it tends to make this sort of thing "show" up. High limit thermostats, generically, can become intermittent too. Everything's suspect.
why hasn't anyone checked the filter in the gas inlet
unless I missed it of course
. These can easily become blocked, not just by small bits of muck in the gas but also large bits of green coming off the inside of the pipe where the installer used the wrong flux. A blockage here can take the pressure down to nothing.Please tell me I'm wrong and someone looked at it? Usually it means taking either a piece of pipe in the boiler, or the gas valve, out.
As said on the first page, the pcb's are weak points, they crack through the middle so flexing them by pressing on the control panel knobs can show the problem. They are solderable, though that's a dubious thing to do on a board, with safety aspects etc, and the rrp is £224 + vat on the partscenter list.
On this boiler, I'd now use a beeping continuity tester and check all the switches and bits of wiring loom I could. Sometimes poor crimping of the end of a wire breaks the conductors inside,or the insulation-displacement metal spikey bits on connectors miss, and brush the edge of the conductor inside. Freezing spray is commonly used by electronic engineers because it tends to make this sort of thing "show" up. High limit thermostats, generically, can become intermittent too. Everything's suspect.
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Actually I'm a girl but no offence takenchrishutt said:
All the advice given has been really useful (altho most of it has gone way over my head) and it has definitely given me some confidence when speaking to BG reps.
The point with the flow switch makes sense. Do you think it could be a problem with water pressure? I mean, could it be that when the flat downstairs turns their tap on the water pressure drops below what the boiler needs and cuts out? Is that a possibility?
ChrisR, don't think anyone has checked the filter on the gas inlet but will ask them when they come round tomorrow.
The boiler might stop, it certainly wouldn't lock out.
That covers the flow switch on the hot tap water.
The other flow switch (checks the pump is running) IS tested when the boiler is first turned on (with no demand) as well as during normal use.
so A) the boiler could lock out a few seconds after being switched on , or b) at any time it's in use. But any engineer would SEE the switch being operated - it's on top.
Checking the switch actually works (which anyone would do if they saw a leak near it) is one of those things which you'd do with a continuity beeper or a voltmeter - standard stuff I'm sure BG guys would check.
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ChrisR said:
I beg to differ, Chris.
If I left the hot tap running the relay inside the boiler used to make noises that sounded like sporadic machine gun fire - and then the boiler would lock-out. It would then take up to ten times to reset it - until it reached the stage where it wouldn't reset at all.
I still think the flow switch/ flow rate needs fully checking out. The symptoms are identicle to those that I had.
joe
ChrisR said:
This sounds very near the mark because it does do both 'A' and 'B'. I'm not sure if anyone has looked at the switch (because I don't know what it looks like) but to be honest I wouldn't be surprised it they hadn't checked it. And also, there is a leak on the boiler.
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Penster said:
Who knows. The noise was the relay opening and closing quickly. I can only tell what happened in my circumstance. Why don't you contact the manufacturer's engineer now that you have a good grasp of the situation?
joe
Beg as much as you like, Joe, it's because don't know what you're talking about.
The Subject is Penster's combi and not someone else's, which shouldn't have been mentioned in the same thread. I will say that the problem you are describing is obvously different. I refuse to comment on it in the wrong thread. Whether it's similar or not is of no interest. Boiler fault diagnostics is not done by finding someone who thinks they had a similar sort of problem on some other boiler and wants to make a lot of noise about it. All that does is confuse the issue.
Ask if you don't understand by all means, but if you think someone with a lot more knowledge on a subject is wrong, it's usually because you don't understand - fair comment?
The tap water flow switch only works if there's enough mains pressure to operate it - whether that's through pressure or flow.
In a block of flats where the mains is poor, the flat downstairs will deprive the upper one of any mains supply so the flow switch returns to the OFF position and turns the boiler off just as though the tap had been turned off. That should not take the boiler to a fault mode.
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They all work on the same principle. If you know so much about it - why can't you say what the fault is?
I had 4 people like you looking at it - and none of them knew what the problem was. Sounds familiar doesn't it?
All I'm saying is that in my case the flow switch was responsible.
Are you saying that it couldn't be here? If so - why was it with my combi?
joe
I had 4 people like you looking at it - and none of them knew what the problem was. Sounds familiar doesn't it?
All I'm saying is that in my case the flow switch was responsible.
Are you saying that it couldn't be here? If so - why was it with my combi?
joe
You're trying my patience. That question is about the most stupid I've seen this year.
We don't know what the fault is yet. It's intermittent. We don't know all about it, but we do know that it doesn't help to discuss fault symptoms which this boiler does not have. Got it?
SO what? You and your boiler are irrelevant to this one.
Different symptoms different fault. AND WRONG THREAD.
Take two corgis. Both yelping in pain. "A" isn't limping. "B" is limping and has a bad foot. What does that say about the possibility of "A" having a bad foot? B*gger All . NOW have you got it?
I'm not going to answer you off-topic here any more. It isn't fair to the customer.
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