National Grid

[jaydebruyne]

Went to service a boiler today.
First tests I do is tightness/letby and then working pressure at meter and inlet on gas valve.
I was getting 10mbar at the meter working pressure. They only have the boiler, no other appliances in gas.
Boiler is a Worcester Greenstar 40CDi conventional.

Called transco as could have been a dodgy regulator. Or undersized pipework but I wanted to rule out the regulator first as standing pressure was only 21mb.

They attended when I wasn't there and changed the regulator but said nothing was wrong with the old. But they tested the meter/pressure when the boiler was in 'condensing mode' - you know when you restart the CDi's and it does the minimum rate thing for about 20 mins.

So he got a normal reading, as did I on minimum rate. But as soon as it got to max rate went straight to 9.5mb at the meter.

Turns out the run needs upping from 22 to 28 - apparently a guy did a new run which is about 9 meters with let's say 8 elbows in 22 and said everything was fine. They'd also left a 4m run of pipework completely unsupported practically hanging in mid air.

Question: do national grid have to know about boilers? Surely they'd know the boiler was in min rate mode and should have waited for max rate to kick in? Or do they rest the regulator differently?

Have turned off the boiler. Owner is gutted as they've just paid £30k having the kitchen tiled in cement tiles which is over the new gas run. Oops!

 

[Atouchofgas]

Cut in test point under boiler, 2 x gauges if it's 9 at test point and 10 at meter your pipes fine.
Have they done a mains upgrade and shoved plastic up the old service?
Discon flexi at ecv and let it blow maybe water in mains?

 

[jaydebruyne]

That's utter bollox telk them to sort there side out first working pressure of 10mbar and under isn't acceptable and doesn't matter what size output pipe is still be the same

So call them out again??? :/ thing is, he said NG won't put it forward as a low pressure callout if the pipework is undersized. Hate being the new boy sometimes, now I'm gonna loook like a right idiot to my customer

 

[ShaunCorbs]

Cut in test point under boiler, 2 x gauges if it's 9 at test point and 10 at meter your pipes fine.
Have they done a mains upgrade and shoved plastic up the old service?
Discon flexi at ecv and let it blow maybe water in mains?

10mbar meter
8 mbar boiler

so not a million miles out

 

[ShaunCorbs]

So call them out again??? :/ thing is, he said NG won't put it forward as a low pressure callout if the pipework is undersized. Hate being the new boy sometimes, now I'm gonna loook like a right idiot to my customer

give me tonight have a mate who works for national grid, will see what he says

 

[jaydebruyne]

give me tonight have a mate who works for national grid, will see what he says

Cheers Shaun

 

[mfgs]

You are getting a 2mb drop from meter to gas valve in the boiler? Worcester allow a drop internally so the 2mb is fine

 

[ShaunCorbs]

Cheers Shaun

think its all bull tbh

 

[ShaunCorbs]

Cheers Shaun

think its all bull tbh

 

[newcastle phill]

10mbar meter
8 mbar boiler

so not a million miles out

Sounds about right including gas valve test point press drop but even if pipework was undersized you should still get a working pressure at the meter within spec regardless Jay.
How are you measuring pressure - digital or manometer. Water guage or single sided. If single sided you have got right fluid in. I know you had an issue the other week with a vaillant.

 

[wattsie1987]

Undersized internal pipework was NCS providing safe working of all appliances can be achieved. Now is just a recommendation. And how can you test the internal pipework with an AR meter installation? Tell them you've done your calcs and the internal run is satisfactory. At the end of the day the customer is paying for a service they are not providing them with ie 6m3 at 21 +/- 2.

 

[jaydebruyne]

Sounds about right including gas valve test point press drop but even if pipework was undersized you should still get a working pressure at the meter within spec regardless Jay.
How are you measuring pressure - digital or manometer. Water guage or single sided. If single sided you have got right fluid in. I know you had an issue the other week with a vaillant.

I use a regin premiere gauge with the regin fluid. I double checked my gauge on my meter at home and it's working fine.

Thing is, at gas college, teacher said if all appliances are on and pipework is undersized the working pressure can drop below the nominal. Is this not true then?

 

[jaydebruyne]

Undersized internal pipework was NCS providing safe working of all appliances can be achieved. Now is just a recommendation. And how can you test the internal pipework with an AR meter installation? Tell them you've done your calcs and the internal run is satisfactory. At the end of the day the customer is paying for a service they are not providing them with ie 6m3 at 21 +/- 2.

Very true. Why would NG say that they won't do anything until the pipe run is upped to 28mm?

 

[wattsie1987]

I use a regin premiere gauge with the regin fluid. I double checked my gauge on my meter at home and it's working fine.

Thing is, at gas college, teacher said if all appliances are on and pipework is undersized the working pressure can drop below the nominal. Is this not true then?

Never heard that before, can't see how it would either the other way round maybe if less than 19 at meter a larger drop across installation would be negligible tho I think.

 

[newcastle phill]

There is one stupid exception. Im sure youve heard the "peak time" caveat.

Otherwise if overall demand is upto 6m3 on a typical domestic meter then it should pretty much be in the ballpark at the meter.

 

[Last Plumber]

Your problem is either a blockage in main or undersized main.
The Nat Grid would have turned that off if they had seen it so low and investigated it.
They won't go around messing with appliances to set them on full rate. If you have an issue like that, you'd be best to arrange to meet on site and you ensure that you set the appliances running on high rate.

The internal pipe work is nothing to do with it by the sounds of it.

The only way that internals could effect the service is if you're pulling too much gas through it for it's size.

 

[jaydebruyne]

Your problem is either a blockage in main or undersized main.
The Nat Grid would have turned that off if they had seen it so low and investigated it.
They won't go around messing with appliances to set them on full rate. If you have an issue like that, you'd be best to arrange to meet on site and you ensure that you set the appliances running on high rate.

The internal pipe work is nothing to do with it by the sounds of it.

The only way that internals could effect the service is if you're pulling too much gas through it for it's size.

I was there with them in the 2nd visit and ran it at max rate. So he witnessed it at 12mbar. He still said up the internal pipework before we can call it in as low pressure service side. He also stated the next door had no issues and that's as far as he investigated as he had no ecv test points. He also said the boiler could be pulling too much gas through the pipework.

Can you buy ecv test points in the web? Might just test it myself for a definitive answer

 

[wattsie1987]

Not sure try bes

 

[jaydebruyne]

There is one stupid exception. Im sure youve heard the "peak time" caveat.

Otherwise if overall demand is upto 6m3 on a typical domestic meter then it should pretty much be in the ballpark at the meter.

I have. But this was at about 11:30am and then again at 3pm and last time at about 7pm which was the only peak time test.

 

[newcastle phill]

Yeh there is no definition of a peak time - thats whats stupid about it.

 

[jaydebruyne]

Yeh there is no definition of a peak time - thats whats stupid about it.

Lol furry muff!!

 

[jaydebruyne]

Not sure try bes

It's and inch connector isn't it?

 

[jaydebruyne]

give me tonight have a mate who works for national grid, will see what he says

Did you manage to speak to your mate Shaun?

 

[ShaunCorbs]

Did you manage to speak to your mate Shaun?

yes he said its strange and not uncommon for that excuse

 

[newcastle phill]

Speaking of strange - netflix - stranger things....mint

 

[Ric2013]

He also said the boiler could be pulling too much gas through the pipework.

Did he explain HOW the boiler can possibly be pulling too much gas through if the run from the meter to the boiler is undersized? Surely the boiler would be UNABLE to pull through too much gas as it has a restriction and so the pressure at the _meter_ test point would be quite normal, and only the _boiler_ end of the restrictive run would have a low pressure?

Not being a gas installer myself, I'm assuming gas behaves much like air, or indeed any other fluid, and doesn't have mystical properties.

 

[joni os]

Venturi effect at test point.

 

[jaydebruyne]

yes he said its strange and not uncommon for that excuse

So call them back out? Either way I have to upgrade the pipework so may just wait until that part is done then they have no excuse

 

[ShaunCorbs]

So call them back out? Either way I have to upgrade the pipework so may just wait until that part is done then they have no excuse

problem is that wont fix it, best have a word with your cus as there paying your bill

from the meter how much exposed pipework can you get at?

 

[jaydebruyne]

problem is that wont fix it, best have a word with your cus as there paying your bill

from the meter how much exposed pipework can you get at?

About 4m in the basement from meter then disappears under flooring

 

[ShaunCorbs]

About 4m in the basement from meter then disappears under flooring

up that first as the rest aprox 6 m with 2-4 elbows should be fine