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Working pressure effecting combustion.

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Knappers

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Ok so I called gassafe today to check hoe to clasify low working pressure and was told if it's not effecting combustion then just note it as a fault (ncs) if it is then it's AR.
I've always worked on the principle that when it's close to 14mb or below I'd put it AR and if it was badly effecting combustion ID.
My principle being that possible explosive start-ups and corrosion caused by poor combustion are potentially dangerous and that 14mb is just too low not to take seriously.

Apparently I have no leg to stand on but I still disagree!?

What's your oppinion?
 
Some boilers can run at as low as 14mb and still work fine without performance issues. All I would do is test its safety and follow manufactures guidance. Take evidence of readings and make note of the issue and present it to the customer letting them know of possible effects.

It could be 14mb when you test it but what happens during high demands, that will lower it even more. Also with other gas appliances running it will lower it even more. I would personally AR it.

I don't agree but what gas safe says goes I guess.
 
A.R.
It's not going to miraculously get better.
Ultimately it's your call, not Gassafe.

As you are now, if you've found a boiler working at lower than normal pressure it's a judgement whether to leave it on.

However if you went to a boiler someone else had A.R'd with the same 14mb, I think it's most unlikely you, or any other GSR would put it back into service without fixing it.

What's the difference?
 
On the job that prompted my query the pressure is just over 14mb but it's clearly been piped in 15mm even tho boiler tail is 22mm and really wouldn't be hard to change, it's also one of many rentals that the customer owns so I'm going to stick to my guns this time.
 
14mb working is ok so long as it's maintained with other appliances working and also maintaining 1mb drop accross the installation pipework. Have you tested working at the meter?
 
1mb across installation I'm not bothered about (I didn't put it in) if it was less than 19 at the meter I'd consider calling transco (or whoever do it now).
It's 22mb dynamic at meter and piped in 15mm.
Granted 14mb is on gas valve so could be as much as 16mb before it, but it's still a crap job that needs putting right IMO
 
Ncs for me aslong as it’s running right
 
Your right I'm sure but would the fact that they replaced the hob burners with random ones from a different hob that rocked around and were clearly dangerous (in a rental property) maybe cause you to be a bit stingy with the rest of the installation too?
Obviously I made that safe...
 
This really depends on what you are measuring at the gas meter say if its 20mbar working pressure and 14 mbar at the boiler then the pipework is undersized , if its 18mbar or lower working pressure at the meter I would be getting cadent out to either tweak the regulator or replace it if necessary I personally would not leave 14mbar especially if there are other gas appliances Hob would be ID for me . Kop
 
I'm with you but it's not what gassafe say.
If it's not impacting on combustion it's 'officially' NCS and even if it is then only AR.
That's with other appliances running (3/4 hob etc)
I was a originally a commercial engineer and certainly wouldn't leave a big forced draught burner running at 14mb, but then you don't get so many cowboys undersizing pipe on commercial;)
 
Had one myself for a lettings agency boiler running at 15mb and 5 mb drop from meter. The boiler is under warranty and the Gas valve needed replacing but the wouldn't do it because it's not been installed to manufacturers instructions so it does matter .
 
Where are you measuring the 14mbar, I remember having an issue with a Vaillant ecotec pro, we were installing them on a council contract, Vaillant were convinced the gas pipework was to blame, it was 22mm from meter to boiler, only appliance in the property, the gas board could only get a maximum 19mbar working through regulator, I cut a test point into pipe at boiler and registered 19mbar working, at that point the Vaillant gas valves were fitted with a flexible hose from gas inlet and it was restricting the 5mbar didn’t here the outcome after that, you’ve already confirmed pipework is undersized so that’s got to be AR, any combustion problems and it’s ID, end of the day it’s been installed like that, I guarantee it’s not been commissioned and there’s no trace of who done it, your last in so you can only advise the necessary works to bring it up to standard and let them sign the warning notice, I wouldn’t take a voice conversation as legit even from gas safe I’d want it in writing, always cover yourself
 
Knappers said:
I'm glad I've not got you servicing my boiler @Dake205, I still haven't put that loft ladder in:)
Click to expand...
There’s always fine lines personally that’s more of a health and safety issue that a lazy engineer would use to justify not doing it, other problems require we have to jump up lofts or crawl under floors so why make an excuse when it comes to a boiler
 
In effect NCS was just removed from tb001 to make IGEM/G/11, it may not be as official but it's still a thing untill we come up with another term to describe it like 'Advisory' or 'not best practice',
Just because it stoped being a requirement to classify NCS situations doesn't mean all those issues disappeared.
Personally I think it just made the Igem/g/11 allot less usefull than before
 
I have to disagree. The intention of the amendment to the risk classification was to remove ambiguity surrounding NCS,
By removing NCS from the Unsafe situations guide there is now a clear distinction between issues that are a clear and present danger ID and those that could become so AR. minor defects, as you stated could be noted by the engineer in foot notes using what ever other classification they see fit.

Our primary goal should always be safety and prevent the risk/danger to life or property?
So taking the OP’s query as an example it’s an “at risk” to me all day.
 
If the combustion readings are ok how would you justify AR ? the conversation with the customer would be interesting..... yes your boiler is running fine and is completely safe but I am turning it off because the gas pressure is low and I don't like it.
 
No one has said to switch it off, you can advise combustion is currently ok but there’s other issues which might in future affect performance, let’s take a different scenario he keeps his mouth shut, signs it off as ok, 2 months down it starts playing up customer phones manufacturer, they come and won’t touch it as it’s clearly not piped correctly, commissioning not completed, warranty is void they can’t get installer but you signed it off so who now looks like the dafty, customer is going to think you’ve not done your job right and you take the grief when it’s not your install, you’ve took £50/60 for a check only and they want it sorted as they feel you’ve failed to do it correctly so is it worth it, it’s not hard to tell them it’s not right and doesn’t meet manufacturers instructions and if they don’t want it sorted but left on then sign your sheet advising them your concerns, what would be hard would be to regain their respect and trust to do a job properly when they find this out
 
bill577 said:
If the combustion readings are ok how would you justify AR ? the conversation with the customer would be interesting... yes your boiler is running fine and is completely safe but I am turning it off because the gas pressure is low and I don't like it.
Click to expand...

Hey Bill, I see your point. But I fear that fails to to take into account what may happen under ever changing variables. For example. What would happen if the regulator on the meter was on the blink and started restricting the supply to the boiler at high demand. Would you be confident that given that scenario the op would still get the same pressure reading given the undersized pipework?
Ultimately it’s a risk assessment and personally I tend to air on the side of caution when conducting them and like Dake77 said we have no authority to switch off the system. It purely advisory. Whether your customer decides to take up that advise should not prevent or deter us from giving it. Because if sh*# hits the fan after i walk out that door I can sleep easy knowing I’m covered
 
If you follow the correct procedure if you AR an appliance you have to switch it off (with permission) if the customer switches it back on its their responsability, please don't go down the "what if" route as you will drive yourself mad and finally I never said to keep secret that the installation has faults, let the customer know and leave a paper trail .
 
My understanding was that if there’s more than one NCS then it’s classified as AR, 1 incorrect pipe sizing 2 low inlet pressure, AR requires the appliance to be made safe and notify the responsible user, in this instance the appliance is currently safe so no need to turn off but the defects could cause future problems and should be reported
 
The problem is if it's AR then we should be advising the cust not to use the appliance in writing and giving the same advice verbally.
I have (and will again I'm sure) issued an AR warning cert and advise the cust it's ok to use in the short term - but it's not right.
3.4 on table 9 of unsafe sits says undersized pipework proved to affect combustion is ID so IMO undersized pipework with low working pressure not currently affecting combustion could well be AR!
I think the general logic I'll adopt is, if the working pressure at the meter is high like 21mb+ and at the appliance it's getting close to 14mb then I'll class AR on the principle that meter pressure could happily drop to 19 and that may cause combustion issues.
 
Dake205 said:
My understanding was that if there’s more than one NCS then it’s classified as AR, 1 incorrect pipe sizing 2 low inlet pressure, AR requires the appliance to be made safe and notify the responsible user, in this instance the appliance is currently safe so no need to turn off but the defects could cause future problems and should be reported
Click to expand...
I suppose it depends if you see them as seperate issues and if they compound an issue.
In this instance they are just cause and effect. ie If the pressure isn't low then the pipe isn't undersized.
The question is I guess what's low and what's too low?
I think regardless of combustion anything under 15mb is too low and 14 is an absolute minimum.
 
I agree 1 can lead to the other however until pipework is sorted and you can confirm that was the low pressure issue in this instance, I’d say they should be classed as separate, what hpns if you advise that changing the pipework will sort the issue and it doesn’t
 
I don't know why it wouldn't, but they're not compounding issues, one doesn't make the other worse so for me it wouldn't change how I'd class the fault.
Undersized pipework and low pressure at the meter - that compounds
Poor combustion and inadequate flue terminal clearance - that compounds
I don't know why I'm arguing the Point tho as I'd AR it anyway :)
 
I don't really understand gassafe their quite happy to let you make your own mind up but in the one time in 10years I got inspected the fella got really upset when I didn't get out the stopwatch for a drop test and said I'll time it if its dropped after I put my tools away.
I got the timer out :rolleyes:
 
There still there just note down / advise but don’t act on which is what was done before but still there
 
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