Is this a reliable test?
A gas test for the whole pipework / appliances was done using the test point on the gas meter. All appliances were turned off. The test showed that the system is gas-tight.
Will this test show up any leaks in the pilot burner section on an electronic CH boiler?
Cic.
It shows that the pipework and fittings up to but not beyond the isolating valves at the appliances are OK.
That is good to know.
No, because that is on the appliance side.
.andy
To email, substitute .nospam with .gl
No. It tests only from the maintap to the taps on each appliance, which usually means up to each burner, and oven and grill, tap on the cooker.
"Thanks both for the replies which confirm my suspicions.
What is the best way to check the connections in the pilot burner section bearing in mind that the burner is in the combustion compartment? Is it safe to squirt test liquid at the pilot jet connection with the front of the combustion chamber removed and main burners lit?
Cic.
The test will only check up to the isolating valve on the appliance (if turned off) or the working valve/tap or whatever is turned on.
To test for a leak on the pilot burner (whther permanent or temporary) use leak detection fluid (approved non corrosive soap solution). Obviously when the pilot is running.
=============== Thanks for that information - I'll get it tested tomorrow.
I should have been a bit more precise in my original post. I meant that all appliances were turned off by their own controls ( thermostat etc.) rather than the gas isolating valve but the answers I've received make the position clear.
Cic.
I presumed from you original post that you had concluded that you probably had a gas leak on the pilot supply tubing (because you perhaps had smelt gas or some such).
It would be very hard to detect a small leak of gas inside the sealed combustion chamber. If it's big enough the leak may become ignited and might be visible if there is a viewing window.
Anyway to help further I would need you to give some more background as to why you are hunting for a leak on the pilot tubing.
===========
My boiler stopped working and I followed the fault finding routines in the boiler manual. In the course of fault finding I replaced the air pressure switch and the PCB. Neither replacement cured the problem and I eventually discovered that one of the air pipe connections on the fan was completely blocked by limescale. I cleared the blockage and reassembled everything. The boiler then started immediately. Apparently this problem (lime scale blockage in fan air connection) is known to Glow Worm but not documented in the fault finding process in the manual.
Having replaced so much in the boiler I decided that it would be worth replacing the pilot jet burner as it looked a bit burned. I asked a Corgi fitter (found in Yellow Pages) to replace this item as I do not now do the 'gas' work myself. He removed the old pilot burner and in the course of removal the fixed pipe from the gas valve to the pilot connection was broken - either as a result of being over-tightened originally or because of damage caused by localised heat. He then got a new fixed pipe and fitted it and completed the job by fitting the new pilot burner.
Having completed this job he then tested the system at the meter as explained in my original post. This was the reason for my original query as it seemed clear to me (confirmed by replies to original post) that such a test could not test the work he'd done since the pilot burner section is effectively switched out when the boiler isn't operating. In fact the meter test he did was really rather pointless in the circumstances which suggests to me that he didn't really understand what he was supposed to be testing. That's quite worrying from a Corgi gas fitter.
In fact I'm not very bothered by the situation because I've confirmed that there is no leak at the junction of the fixed pipe / gas valve and as you pointed out any minor leakage at the other end (inside the combustion chamber) would burn off harmlessly without any danger of a a buildup. I can only assume that the fitter was sufficiently confident in his ability to make two simple connections without the necessity of testing the connections. However, I would have been happier if he had done a simple test to confirm the standard of his work.
Sorry about the long reply but necessary to explain the situation.
Cic.
SNIP
"Limescale"??? This infers a leakage of hard water into the fan/flue system somewhere and I seriously doubt that it has happened more than once or twice in Glow Worms wide experience. I can visualise debris or dust blocking the sensing tube and have often come across this situation on a variety of boilers. Sometimes rain can enter a vertical discharge fan flue and flood into the sensing tube causing a failure to sense the fan but then dries out and hence an unexplained transient fault.
You say you do not do the "gas work" yourself but when you replaced the PCB did you think to check the calibration of the boards modulating output to the gas valve (assuming you have a modulating burner of course) Part of the gas system commissioning checks involve the rate at which the burner uses gas and even though no gas connections were opened by you this still requires rechecking.
You should be grateful that he was conscientious enough to check that the pipework system of the house was sound and there was no hidden corrosion which had started a minor leak ready to get progressively worse. In fact as the last "competent person" to visit he would have been asked at length about the checks he had carried out in the event of a future gas leak or other reportable problem.
You are absolutely, definitely sure he didn't spray a little leak detector spray or smear some leak detect liquid at the gas valve to pilot pipe outlet connection then? Quite frankly I think your attitude is somewhat strange since you have already said you are satisfied that the pilot pipe joints are ok. - Or are you upset that you didn't check the sequence properly first before spending money on an unneccessary PCB replacement?
==================== Yes, Limescale. I mentioned this to the fitter and he stated that it's a known problem due to condensation. He didn't say how frequently it occurred because this was only a casual conversation. ====================
==================
======================= The service manual makes no mention of any checks after replacement and there is no indication anywhere in the manual that there is a modulating burner. ===============
================>
============== Of course I'm grateful but that wasn't the point of my question. The question was simply whether the test he did at the meter would detect leaks in the pilot burner section. The answer to that question was given in both previous replies which clearly state that such a test would not test the pilot burner section. It was a simple question and I got two similar straight forward replies. It wasn't contoversial and it wasn't intended to be so. ==================
================ Yes, I'm certain. I was present the whole time and could not have failed to see if anything had been used.
=================
================== My attitude is not all strange. I asked a simple question to confirm that my understanding of the system is correct - namely that the pilot burner section is effectively isolated when the boiler is not operating. As stated above the two original replies to my post confirmed that fact and also confirmed that the test at the meter could not show up leaks in the pilot burner section. I'm not remotely upset that that I spent money on a replacement PCB and air pressure switch. Since they're in working order they are spares for future use if and when necessary. If I were interested in cutting corners I certainly wouldn't have gone to the expense of paying a fitter to replace the pilot burner which was clearly working. My attitude is quite simply that I want to ensure that my system is working correctly and safely.
There was nothing controversial or critical in my original post or subsequent explanation. I simply asked for information and I don't understand why you should choose to make the matter controversial. From time to time there are posts here which suggest that 'Corgi' qualification is no guarantee of competance, and many of us watch TV programmes such as 'Plumbers from hell' which make it plain that it's up to the consumer to protect themselves from cowboys. By asking a question I simply exercised my right to know about the job I paid for.
I hope this puts your mind at rest. I'm not looking to criticise - simply to be informed.
Cic.
In message , Cicero writes
How do you get limescale from condensation ?
Condensation being condensed water vapour - which doesn't carry calcium carbonate with it in the vapour state
============ I don't know how you get limescale from condensation. I reported what I saw - it appeared to be limescale - and the fitter confirmed this.
Cic.
My point exactly Geoff! Whatever the bit of crud blocking the sensing tube - it would take a chemical analysis to convince me it was lime (calcium) based
The general tone of your posts gave the impression (to me at least) that you were simply looking for support from the corgi bashing brigade in your (implied) criticism of the installer you used. I'd have been a bit more impressed if you had asked your question of the guy you employed, and obviously watched while he did the work, before the world at large. If he had been given the opportunity of answering your concerns he may have put your mind at rest straight away (or perhaps not but afterwards its hard to say). My mind is at rest
I've seen this when a boiler that my parents used to have was cleaned. It had copper components in the heat exchanger and there was usually a white crud around the burners and pilot jet which could be normally hoovered away but sometimes needed to be scraped. It did look like lime scale.
I took some once and added water to it and it immediately became the bright blue of copper sulphate. Therefore I suspect that it is some form of copper salt which is normally kept in an anhydrous state by the heat inside the boiler.
Other than blocking things, it didn't seem to have any other delterious effect.
.andy
To email, substitute .nospam with .gl
============== In your haste to criticise and make controversy where none exists you contradict yourself.
You stated,
"Limescale"??? This infers a leakage of hard water into the fan/flue system somewhere and I seriously doubt that it has happened more than once or twice in Glow Worms wide experience."
I don't know whether the 'once or twice' is derived from Glow Worm or whether you've invented it. I doubt if it's an official figure from Glow Worm since they certainly can't have had access to data from all serviced boilers. However, common sense indicates that if it can happen 'once or twice' it can happen again. In fact your assertion that it isn't limescale doesn't make much sense since you admit that it can happen and has happened in the past however infrequently. Neither you nor Glow Worm can know how frequently it occurs because nobody knows how many times it has happened and not been reported.
More to the point is that I discovered and cleared a blockage which isn't documented in the fault finding routine outlined in the Glow Worm manual supplied with the boiler. It doesn't matter what the blockage was except to you who wanted to create controversy for your own satisfaction.
You go on to state,
"...that you were simply looking for support from the corgi bashing brigade....."
That is something straight from your imagination. In fact your choice of words ".......corgi bashing brigade....." suggests that you have a large chip on your shoulder. Most of the criticism of Corgi and Corgi trained people I've seen appears to come from other competant gas fitters who are in a better position than me to judge the standards of Corgi people. If I had been in the 'corgi bashing brigade' I certainly wouldn't have looked in Yellow Pages specifically for a Corgi Registered fitter to do my job. I chose Corgi because I've had previous experience of them and that ought to provide some degree of security.
You really ought to remember that this is a DIY group. People come here for help and advice so that they can do their own work successfully and safely. It's also visited by professionals who freely offer their very welcome advice. If you had taken the trouble to read the full thread you would have seen that I asked a very simple straightforward question which received two satisfactory replies - the first within 8 minutes and the second in less than 2 hours. A third poster also offered advice and asked for further information which I supplied fully. You alone chose to make the thread controversial because you have some kind of personal axe to grind.
I didn't ask '.....the world at large....' for something critical of the person I employed since this is an anonymous group and his identity will never be revealed. I asked for general information for my personal satisfaction and I was satisfied with what I got from the other posters. You have provided no help whatsoever.
Cic.
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