https://www.diynot.com/forums/viewtopic.php?t=246442

[PEDANTICVINDICTIVEMAN]

Looking on page 28 far right paragraph, I am having trouble understanding how it says " if the boiler is supplied by 28mm pipe, runs 1-2 2-4 and 22mm tube for 4-6 the re-worked pressure drops are 0.18 + 0.13 + 0.17 =0.48mb" I am not seeing this on the chart, am I missing something ?

 

[doitall]

Not sure what you're asking ped, and the link only takes you back to the same page.

If you want to discuss gas pressure send me an email.

 

[PEDANTICVINDICTIVEMAN]

https://www.diynot.com/forums/viewtopic.php?t=246442

http://www.ukcopperboard.co.uk/lite...ion-Tips/Domestic-gas-planning-and-sizing.pdf

 

[doitall]

That makes sense.

1-2 has to take the total load of 3-5-6.

2-4 has to take the load of 4-5.

4-6 has to take the load at 6.

 

[PEDANTICVINDICTIVEMAN]

So why are the figures in the paragraph, different to figures on the chart ?

 

[doitall]

Ss what you mean, there's a few errors in the chart and the para

 

[PEDANTICVINDICTIVEMAN]

Right, thought it was me not understanding it

 

[doitall]

Are you happy with that or do you want me to work out what they should be.

 

[PEDANTICVINDICTIVEMAN]

No thats fine, I can work it out thanks, but one question, Kw divided by 38.5Mj/m3 then x by 3.6, what is the 3.6 relating to ?

 

[D_Hailsham]

No thats fine, I can work it out thanks, but one question, Kw divided by 38.5Mj/m3 then x by 3.6, what is the 3.6 relating to ?

I think you are mis-reading it.

To determine the gas-rate for an appliance divide the appliance heat input in kW by the ‘calorific value’ (CV) of the gas being burnt. In the case of natural gas this is 38.5MJ/m3.

For example, for a 10kW appliance the flow rate will be: 10 ÷ 38.5 = 0.26 litres/second.

This figure can then be multiplied by 3.6 to convert the flow rate from l/s to m3/hour = 0.26 x 3.6 = 0.936m3/hour.

So the 3.6 converts from litres per second to cubic metres per hour. 3600 seconds = 1 hour; 1000 litres = 1 cubic metre; 3600/1000 = 3.6.

 

[D_Hailsham]

No thats fine, I can work it out thanks, but one question, Kw divided by 38.5Mj/m³ then x by 3.6. what is the 3.6 relating to ?

It does explain where it comes from.

To determine the gas-rate for an appliance divide the appliance heat input in kW by the ‘calorific value’ (CV) of the gas being burnt. In the case of natural gas this is 38.5MJ/m³.

For example, for a 10kW appliance the flow rate will be: 10 ÷ 38.5 = 0.26 litres/second.

This figure can then be multiplied by 3.6 to convert the flow rate from l/s to m³/hour = 0.26 x 3.6 = 0.936m³/hour.

So the 3.6 converts from litres per second to cubic metres per hour. 3600 seconds = 1 hour; 1000 litres = 1 cubic metre; 3600/1000 = 3.6.

 

[PEDANTICVINDICTIVEMAN]

Ah got it now thanks 36000 seconds in an hour

 

[D_Hailsham]

Ah got it now thanks 36000 seconds in an hour

Read what I said again! There are 60 secs in a minute and 60 minutes in an hour. So 60 x 60 =3,600, not 36,000!

 

[PEDANTICVINDICTIVEMAN]

Ah got it now thanks 36000 seconds in an hour

Read what I said again! There are 60 secs in a minute and 60 minutes in an hour. So 60 x 60 =3,600, not 36,000!

I was wonder wondering when you'd spot that one Wilson

 

[D_Hailsham]

Wilson

Watson?