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JLS

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Still training so unable to post this in the GSR forum but I don't think it contravenes the no advice about repairs rule, my apologies if I'm wrong.

Question is what's the rational of taking readings over a two minute period for a metric meter when one sweep of an imperial meter can be about 40 seconds?

I am also confused as to why you can get high meter standing pressure readings. Other day I did a tightness test and despite being very slow with the ECV I got nothing on the gauge until the valve was almost fully open at which point it shot up to 29mb, repeated the test moving the ECV at the same rate and it acted quite normally and stopped at 21.5mb. Mentioned it to the engineer I'm working with and just got told it must have been my error. I can't see what I could have done wrong other than locking up the regulator but then isn't the regulator there to prevent such high pressures.

Just find it confusing so if anyone can give me an explanation I'd appreciate it.
 
You can do one for 60 seconds and just double the gas usage or 30 seconds and x by 4 etc

Were you using a digital gauge or water ?
 
You can do one for 60 seconds and just double the gas usage or 30 seconds and x by 4 etc

Were you using a digital gauge or water ?
Water gauge and I realise that it's just a case of changing the multiplying factor , I was just wondering what the rational was for being told two minutes. Questions like that just tend to nag at me I'm afraid so I thought I'd ask.
 
The 2 minute thing is one of the common misunderstanding you come across in our line of work.
It originally came from the time the digital meter appeared, (meaning a REAL digital meter with electronic readout)
The reason for this is that the readings are displayed by a fairly random pulse on an electronic display, (my way of describing it).
If you watch one, you'll see that it will skip figures, so for example, instead on counting like a clockwork dial, 1,2,3,4,5,6,7,8,9
It will pulsate readings so they only change every few seconds
e.g.1,2,4,5,6,9, etc
This makes them slightly more inaccurate over one minute, hence timing for two.

The metric meters, have the same or similar mechanism to the old red test dial meter and are more than likely just as accurate to read as the predecessor (red test dial).

I hope this makes sense?
 
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The 2 minute thing is one of the common misunderstanding you come across in our line of work.
It originally came from the time the digital meter appeared, (meaning a REAL digital meter with electronic readout)
The reason for this is that the readings are displayed by a fairly random pulse on an electronic display, (my way of describing it).
If you watch one, you'll see that it will skip figures, so for example, instead on counting like a clockwork dial, 1,2,3,4,5,6,7,8,9
It will pulsate readings so they only change every few seconds
e.g.1,2,4,5,6,9, etc
This makes them slightly more inaccurate over one minute, hence timing for two.

The metric meters, have the same or similar mechanism to the old red test dial meter and are more than likely just as accurate to read as the predecessor (red test dial).

I hope this makes sense?
That makes perfect sense thanks and allows me to put that one to bed!!
 
I am also confused as to why you can get high meter standing pressure readings. Other day I did a tightness test and despite being very slow with the ECV I got nothing on the gauge until the valve was almost fully open at which point it shot up to 29mb, repeated the test moving the ECV at the same rate and it acted quite normally and stopped at 21.5mb. Mentioned it to the engineer I'm working with and just got told it must have been my error. I can't see what I could have done wrong other than locking up the regulator but then isn't the regulator there to prevent such high pressures.

Just find it confusing so if anyone can give me an explanation I'd appreciate it.

I've been thinking about this and I can only assume the manometer feed tube had folded over on itself preventing the pressure reaching the gauge but that still doesn't explain the high reading (to my mind anyway). Contamination of the regulator sealing face doesn't sound likely as it wouldn't be intermittent. Am I being overly anxious about the standing pressure? Is it a case that so long as it reads right on a second attempt and the working pressure is satisfactory that is what is important?
 
I would not worry about standing pressure to much up to 30mbar it can be effected by atmospheric pressure and tempreture , your first test is letby so you need to reduce the gas pipework pressure to 10mbar for 1minute to check the ECV then raise it to 20 - 21 mbar for 2 mins stabilisation then 2 mins test , thats your tightness test your working pressure is measured at the meter and also at the appliance inlet to check for pressure drop across the gas pipework with all appliance working this should be 1mbar say 21 and 20 in a perfect world, providing your test results equal the manufacturers instructions then do your gas rate i would always do it over 2 mins then you can check its all correct . cheers kop
 
Still training so unable to post this in the GSR forum but I don't think it contravenes the no advice about repairs rule, my apologies if I'm wrong.

Question is what's the rational of taking readings over a two minute period for a metric meter when one sweep of an imperial meter can be about 40 seconds?

I am also confused as to why you can get high meter standing pressure readings. Other day I did a tightness test and despite being very slow with the ECV I got nothing on the gauge until the valve was almost fully open at which point it shot up to 29mb, repeated the test moving the ECV at the same rate and it acted quite normally and stopped at 21.5mb. Mentioned it to the engineer I'm working with and just got told it must have been my error. I can't see what I could have done wrong other than locking up the regulator but then isn't the regulator there to prevent such high pressures.

Just find it confusing so if anyone can give me an explanation I'd appreciate it.


Was the valve the old plug cock type?
 
I would not worry about standing pressure to much up to 30mbar it can be effected by atmospheric pressure and tempreture , your first test is letby so you need to reduce the gas pipework pressure to 10mbar for 1minute to check the ECV then raise it to 20 - 21 mbar for 2 mins stabilisation then 2 mins test , thats your tightness test your working pressure is measured at the meter and also at the appliance inlet to check for pressure drop across the gas pipework with all appliance working this should be 1mbar say 21 and 20 in a perfect world, providing your test results equal the manufacturers instructions then do your gas rate i would always do it over 2 mins then you can check its all correct . cheers kop

Sorry, I can see how my initial post might be misconstrued. What I meant was I'd just done a tightness test as you describe above and was opening the ECV slowly to check that I hadn't locked out the regulator and to take the standing pressure
 
It is perfectly normal to have pressures up to 30mbar at the test point as i said this can be caused by atmosphreic pressure , tempreture, friction in the pipework ect its in your training litreture , standing pressure above 30mbar is what you need to worry about the regulator needs attention by the emergency service supplier phone number will be on the meter hope this is clearer now regards kop.

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20170523_143922.jpg
 
If the test nipple is partially blocked you can get that spike in standing pressure.
 
It's a bloody headache these days gas rating, checking working pressures at meter an boilers etc.

Anything below 19mb I'd switch off an informed national grid.

I'm seeing some national grid engineer's doing nothing, say if it's 17.5mb.

Aslong as it is above 16.5mb then that's ok in some of their lads eyes ?

Worcester want minimum 16.5mb at their boilers they now say, well if I've switched a meter off at 17.5mb it's most likely I'm getting under the 16.5mb. The tactics then get swapped to, is it effecting the safety ?

Well, considering its 1pm on a sunny afternoon today no it's not, but God knows what it will be like in day December?
 
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