Working pressure

[dboi78]

Happy new year !

Although in Practice working pressure is done with the appliance being worked on at full capacity, I have conflicting info regarding the correct way, as I have understood it ALL appliances are required to be on full rate as this tests appliance at worst possible operating/working pressure, but I have recently read info that states only appliance being worked on needs to be on full rate and other appliance are not required to be on at all ?????

 

[keltoyboy]

Working pressure is usually only for the appliance you are working on.....unless you think you have a pipesizing issue then you would check for a drop in working pressuure by working at the farthest away appliance and turning others on to full....

 

[dboi78]

Surely u check working under maximum operating conditions ie all burners on and then check working at said appliance, it's not likely all appliances would be on full at the same time but it is a possibility and as a gas engineer shouldn't all possible circumstances be covered however unlikely ???

 

[fuzzy]

working pressure at the meter or the appliance?

 

[dboi78]

Appliance !

 

[keltoyboy]

unless you have a pipe sizing issue you need only check the w/p on the appliance you are working on.....and as you say if it has been fitted by a competent gas engineer, then there should be no issues with pipe sizing.....but if you are unsure and do think you have an issue with pipe sizing do as i said above after taking a reading at the meter.....and if your drop at farthest away appliance is no more than 1mbar all is ok.....if it is more then you are undersized!!!

 

[fuzzy]

working pressure at appliance is just to check for pressure probs, burner pressure more importamt presuming piping to be correct

 

[dboi78]

Thanks guys I get the pipe sizing issue that's not what I was referring to in my op, what I'm saying is that when all appliances are running does a particular appliance get restricted pressure as installation at maximum conditions or does the regulator/governor make up for this extra demand ?? or have I just answered my own question .............

 

[brightcrow]

Theoretically dboi78, The regulator, as the name suggests should work at same operating pressure whether there is one or five appliances running. However, in practice this has not always proven to be the case as have had mixed results (mainly with the smaller appliances). Generally you should be testing the operating pressure with all appliances at full rate and you should have no more than 1mb drop between the meter and any of the appliances, closest or furthest. This test was designed as i understand it to firstly check there are no restrictions and secondly to confirm your pipe-sizing calculations are correct. Be warned many manufacturers are now publishing the restrictions of their appliance Gas Valves as it is possible to lose over 1mb on the valve alone!

I tend to test operating pressure at meter under full appliance rates as I personally want to test things at their maximum. Have had one or two regulator failures after installing a larger appliance as the regulator internal spring is not used to travelling so far.

 

[johnnyplumb]

Happy new year !

Although in Practice working pressure is done with the appliance being worked on at full capacity, I have conflicting info regarding the correct way, as I have understood it ALL appliances are required to be on full rate as this tests appliance at worst possible operating/working pressure, but I have recently read info that states only appliance being worked on needs to be on full rate and other appliance are not required to be on at all ?????

i think you are better to test with all appliances at max as this would test the installation on a worse case scenario. Where did you read otherwise?