Boiler problem

R

Rogerthedodger

I have an Ideal Minimiser SE50, installed 1999. Recently it was getting noisy when close to control-stat cutoff. I thought I’d try reducing the burner gas pressure. The manual says 3.5in wg, which must be set on commissioning. I hadn’t got that far into the manual when I installed the boiler, and it was OK for years. When I checked it it was more like 5.5in! Reduced it to 3.5in and it was OK, just a touch noisy but much better than before. So I reduced the pressure to 2.75in. After that it would sometimes (not always) fail to fire when called. It would always fire if the control-stat turned down to min, then up again. It’s not the control-stat as the fan runs, and it only runs when the control-stat calls.
As it seemed unlikely the lower pressure would cause the problem, I suspected the flame detector electrode so I removed the burner, checked the clearance and gave everything a good clean. Problem still there so I increased the pressure to 3.25in, and it’s been OK for a couple of days.
Anybody seen anything similar or can suggest anything? Maybe it does need a certain pressure to give enough initial flame for the detector, so if it recurs I’ll up it back to 3.5in. Or maybe the flame detector is dicky, and cheap enough to replace on the off-chance. Only other thing I can think of is PCB intermittent fault. If replacing was a sure cure I’d do it, but not keen as a test. Same only more so with the gas control valve. Gas pressure from meter is OK, about 9.5in.
 
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If only you read the forum rules before posting then you would see that we don't give advice here on DIY gas work.

Most would understand why not!

Tony
 
R

Rogerthedodger

If only you read the forum rules before posting then you would see that we don't give advice here on DIY gas work.

Most would understand why not!

Tony
Measuring and adjusting gas pressure is no issue for a competent DIYer, and I don't consider that "gas work". Can you comment on the problem posted?
 
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Measuring and adjusting gas pressure is no issue for a competent DIYer, and I don't consider that "gas work".
It is considered gas work and interpreting the readings correctly is vital to safe operation of your boiler. We work in millibars by the way. You make no mention of having your boiler serviced or if the upgrade kits have been fitted.
No advice can be given on the public forum, but if you are Gassafe then I would recommend you join the Combustion Chamber section.
 
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R

Rogerthedodger

Measuring and adjusting gas pressure is no issue for a competent DIYer, and I don't consider that "gas work".
It is considered gas work and interpreting the readings correctly is vital to safe operation of your boiler. We work in millibars by the way. You make no mention of having your boiler serviced or if the upgrade kits have been fitted.
No advice can be given on the public forum, but if you are Gassafe then I would recommend you join the Combustion Chamber section.

OK thanks. I'm fully familiar with SI basic and derived units, just that I thought many members on the forum might prefer inches, and my ruler is easier to read in inches!
BTW the boiler is still working OK so I think I've cured the problem.
I only posted the problem hoping for suggestions and a friendly discussion.

Out of curiosity, do you happen to know how the flame detector works? I'm pretty sure it's not a thermocouple. I can only think the flame contains ionised gas and a (very small) current is detected when voltage applied.
 
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You seem to imagine that engineers here are very old fashioned and stuck in their old ways.

Metrification in the UK was from about 1970 which is 44 years ago so longer than an average working lifetime.

Although I agree that many engineers were still working in inches until the 1980s.

Surprisingly to you it seems, we do understand how boilers work! We need to know to be able to repair them!

Tony
 
R

Rogerthedodger

You seem to imagine that engineers here are very old fashioned and stuck in their old ways.

Metrification in the UK was from about 1970 which is 44 years ago so longer than an average working lifetime.

Although I agree that many engineers were still working in inches until the 1980s.

Surprisingly to you it seems, we do understand how boilers work! We need to know to be able to repair them!

Tony
I don't imagine anything of the sort! I'm an engineer myself and use SI almost exclusively, but for low gas pressures I'm equally at home with mbar, mm wg or in wg, as I'm sure are most heating engineers.
Where did I imply you or anybody doesn't understand boilers? I've no wish to fall out with anybody by saying that!
Do you have any ideas about my flame detector query?

Cheers Rogerthedodger
 
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For an engineer you have trouble reading.

You will not get diy gas advice here.

Changing gas pressure is gas work.

If you installed a boiler without read the manufacturer's instructions on setting it up AND didn't have it serviced for 15 years, then you are not a very good engineer either.

One suspects your experience in the engineering extended as office tea boy.


Call a professional before you hurt someone.
 
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I thought I’d try reducing the burner gas pressure. The manual says 3.5in wg, which must be set on commissioning. I hadn’t got that far into the manual when I installed the boiler, and it was OK for years. When I checked it it was more like 5.5in! Reduced it to 3.5in and it was OK

I knew I shouldn't have thrown my imperial manometer away!

BTW OP, how many cubits long is your flue?
:rolleyes:
 
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The other thing the op is not understanding is the idea that information posted here is visible to all and sundry.

Even IF he understands the consequences of the advice, the next person to read it might not.

Common sense really. :rolleyes:
 
R

Rogerthedodger

I thought I’d try reducing the burner gas pressure. The manual says 3.5in wg, which must be set on commissioning. I hadn’t got that far into the manual when I installed the boiler, and it was OK for years. When I checked it it was more like 5.5in! Reduced it to 3.5in and it was OK

I knew I shouldn't have thrown my imperial manometer away!

BTW OP, how many cubits long is your flue?
:rolleyes:

Ha ha freaking ha. See my other posts about units. I probably know more about SI units than you do.
 
R

Rogerthedodger

What do you know about my engineering (and reading) capabilities? Many times I've diagnosed a problem and fixed it when the "experts" were stumped, and that includes boilers and central heating.
What makes you think the boiler hasn't been serviced for 15 years? I've done it regularly.
If the Minimiser is such a dreadful piece of kit it's amazing it has run OK for 15 years and looks good for many more yet.

Most of the replies I've had have made criticisms of various sorts. It seems the only matters that can be commented on are things I can easily sort out for myself. Nobody has suggested answers to my questions.

Come on chaps, it's good to be proud of our skills, but we don't want to get too up ourselves, heating is not such a black art.

I shall now unsubscribe from this forum.
 
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OP, if you want to know how the sensor works I suggest you try the patent office website. There's plenty of patents filed for boilers and the like and I'm sure you'll find something there which answers your question, complete with exploding diagrams and the like.
 

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