No less than 18 mb inlet point

[Inverness]

hi guys. Serviced a boiler today at the meter working pressure 21mb and the boiler 16.5mb. But Worcester say 14 mb at the boiler? Any road 4.5mb drop across the pipework undersized. But my reading ratios where good.
Worcester 37 cdi combi. Cheers

 

[ShaunCorbs]

Length and size ?

 

[Inverness]

22mm pipe about 4meters and 4x22mm bends. I think this boiler requires 3.9 cubic meters of gas an hour. Co2 max 9.7 min 9.3 I'm happy with that. At the meter I run boiler at max and got 21mb. I then attached u gauge at inlet point of boiler 16.5mb at max. I'm now doubting my ability. I'm correct in this order?

 

[Scott_D]

1mb on pipewrk and 1.5 through gas valve
pipework undersizred or a blockage

 

[ShaunCorbs]

I would say check the inlet of the gas valve

 

[Inverness]

With it working at max?

 

[Scott_D]

Any other appliances

 

[Old Account]

I was thinking you are only allowed to have 1mb drop between meter and appliance. Am I mixing something right ?

 

[Scott_D]

Correct
some boiles have a loss through internal pipe and gas valve

I was thinking you are only allowed to have 1mb drop between meter and appliance. Am I mixing something right ?

 

[Chalked]

For a test point, just before the boiler and test again. Bet it’s better.

 

[Inverness]

In worse case situation when you come across a service and the pipe size is too small. What do you do notifiy the client that it's required upgrading or contact gas supplier to tweet the incoming supply.

 

[ShaunCorbs]

cant tweek incoming as its acceptable

depends if it effects gas rate if not juts advise if it does follow the rulings

 

[jtsplumbing]

Problem with things like this when boiler has been in place for some time and as far as customer is concerned the boiler is working OK is trying to convince them that they need gas supply upgrading most will look at cost & disruption involved, you know they wont get it done, if you push them it will be the last time you do any work for them and will take there custom elsewhere, Unless its ID not a lot you can do.

 

[Last Plumber]

Pipe Size sounds OK.
As above, check for a blockage in the Gas Valve filter/or pipe work.
If the filter has Copper Sulphide in it, you may need to clear the pipework too. As that stuff builds up it can heavily restrict the Flow of Gas.
A lot of modern Boilers have a 'bigger than you'd expect' drop from the pipe connection to the Gas valve test point.
To be honest, if its Gas rate is good, pipework and filter is clear and it doesn't effect any other appliances I wouldn't worry about it.

 

[Inverness]

Thank you very much guys you'd have push my ability on to another level. I didn't pass my gas through the help of my employer you guys did it especially thank you too Shaun I wouldn't be where I am because of you. If I could buy you all a pint every time I've needed help I'd be a poor man especially when I'm only getting £8.50 per hour. Thanks I hopefully will continue to pester you guys from time to time with stupid questions.

 

[Scott_D]

Are you the only gas safe person in the company?

 

[Inverness]

There's one other guy and he said it's ok too but I prefer asking your advise. 3 weeks today I'm going out on my own!

 

[KingDoey]

Correct me if i am wrong chaps but is this not AR? The boiler clearly has undersized pipework? Worcester allow 2.5 mbar from meter to inlet on gasvalve.

 

[ShaunCorbs]

Correct me if i am wrong chaps but is this not AR? The boiler clearly has undersized pipework? Worcester allow 2.5 mbar from meter to inlet on gasvalve.

Aslong as it doesn't adjust the figures out of spec they say it's fine down to 14.5 mbar

 

[firemant]

Correct me if i am wrong chaps but is this not AR? The boiler clearly has undersized pipework? Worcester allow 2.5 mbar from meter to inlet on gasvalve.

Unless you can find anything to the contrary, undersized pipework is only the old NCS. Unless it is proved to be affecting the safety of any appliance, in which case it is ID. So either poor combustion resulting in CO to a room, or burner outage on, say, a cooker ring, when the boiler kicks in

 

[Inverness]

I'm getting confused now... if Worcester says 14.5 mb at the inlet and the gas meter working pressure 19mb. From meter and gas inlet valve is greater than 2.5 mb drop.

 

[AWheating]

Think worcester say 16.5 mb. 19 at meter minus 1mb on pipe work minus 1.5 on gas line of appliance. 14.5 mb on sum ideals I believe.

In this situation always test hob on low flame and turn hot water/ boiler on full rate.

 

[johnduffell]

In this situation always test hob on low flame and turn hot water/ boiler on full rate.

Good idea, would be worth testing the hob with 3 rings on high and one on min, just to be on the safe side.

 

[Inverness]

I can't thank you guys enough for your helpful advise

 

[kasser]

To continue with this pipe-sizing thread, isn't it highly likely the pipework will be undersized if it is a 22 mm pipe from the meter feeding several appliances throughout the house?

I've just come across a house with the meter at the front and the boiler and hob at the back and the 22 mm pipe at meter was undersized by my calculations and also after measuring the pressure drop.

Another property I've seen was a meter at the front + 2 small fires + gas hob + gas oven + non-condensing boiler with a 22 mm pipe from the meter to feed all this. Kitchen & boiler were at the back. Thinking back now, this would have been severely undersized?

Last e.g: meter in outhouse, hob + boiler on 3rd floor flat, 22 mm pipe from meter to feed this. So if pipework was undersized in the first e.g, it's most likely going to be severely undersized here?

Yet you rarely see 28 mm pipe from the meter in houses.

 

[dween]

16.5 on pretty much all worcesters

 

[kris]

He's only got 4m of 22mm plus 4 bends so 6m of 22copper. Having 22mm copper gives you press absorb of 0.4mbar so absolutely fine for gas rate of 3.35m3 so you pressure drop must be @ gas valve / inlet .
But just thinking if you've a hob then your missing hob output and tee piece etc.
Inverness what's the total length of copper as Well as how many gas appliances etc