if burner pressure is adequate, with only 1 appliance on circuit.any problems forsee

[markinaark]

if you have 1 appliance ie glowworm ultimate 50ff supplied from meter done in 15mm pipe supplying only 1 appliance. no other appliances on meter,
checked operating pressure at gas valve, 17.45 mb ,
dont want to check pipe before valve as all pipework is buried, and would make sh**te of the job.
have close to 9 meters of 15 mm supplying boiler.
( 1.5cbm/hr ) as per manual
could really have been brought up to 22 mm pipe but wasnt. (typically)
when gas rated boiler its using 1.62cbm/hr
which appears to be within range as per plate
16.64 kw/ 10.4mb 1.54cbm/hr
18.32 kw/ 12.6mb 1.70cbm/hr

now the question is
boiler allowance 1 mb drop from meter to appliance.
actual drop 21 mb down to 17.45. on gas valve maybe a further drop on valve
but appliance only needs 12.6 mb

what i have is
1.62cbm/hr 17.43kw @ burner pressure 11.45mb

so summarise all the above would i be correct in saying .
as long as you are getting the required pressure above burner pressure requirement all should be well.

all coments appreciated.

 

[GrahamM]

Re: if burner pressure is adequate, with only 1 appliance on circuit.any problems for

Range rated so it must meet the MI's spec at the MAX rating.
Firstly the instal is NCS as does not meet minimum of 18 mbar at appliance.
If data plate states a burner pressure of 12.6 mbar max. then I would be looking for at least 12ish to be content. 11.45 mbar is a bit on low side for me, that is 10% down, but it is your call.

There is no way any other appliance could be fed from that supply.

 

[markinaark]

Re: if burner pressure is adequate, with only 1 appliance on circuit.any problems for

No other appliances been fed from it , not a problem there.

Was wondering without breaking into supply pipe.
Would you expect a drop in mbars on the gas valve itself.

I though that as long as gas rate between +5% to -10% would still be within gas rate range.
Thanks for comments.

 

[GrahamM]

Re: if burner pressure is adequate, with only 1 appliance on circuit.any problems for

No other appliances been fed from it , not a problem there.

Was wondering without breaking into supply pipe.
Would you expect a drop in mbars on the gas valve itself.

I though that as long as gas rate between +5% to -10% would still be within gas rate range.
Thanks for comments.

There is a permitted drop if 1 mbar allowed between the meter and the appliance.
There is some permitted calculation error on your gas rate. Unless you have your stop watch activation digit calibrated on a regular basis. As long as it as near as.
The BP is a different matter if it says has to be 12mbar then you must get 12 mbar on your manometer or as close as is readable.

 

[gbgas001]

Re: if burner pressure is adequate, with only 1 appliance on circuit.any problems for

Hi

The appliance is range rated so can be set anywhere betwean the 10.4 and 12.6 mb

The gas valve has a regulator in it to drop the pressure of what is coming in to the supply pressure for the injector / burner. There is no direct relationship between the inlet pressure and the burner pressure BUT U.K. natural gas appliances are G20 meaning there should be 20mb at the inlet unless the manufacturers instructions state otherwise. There should only be a one mb drop in working pressure from the meter to the appliance.

gb-gas

 

[markinaark]

Re: if burner pressure is adequate, with only 1 appliance on circuit.any problems for

so gb if its range rated ,
the gas pressure at the inlet in theory could be as low as 10.6mb ie under gassed etc,
and as long as the burner presure was set below this figure lets say 10.4, it would not really cause a problem , as you are styill getting the right amount of gas and if when gas rated was still okay.(okay would be classified as ncs). but it could still be operating correctly.

 

[gbgas001]

Re: if burner pressure is adequate, with only 1 appliance on circuit.any problems for

so gb if its range rated ,
the gas pressure at the inlet in theory could be as low as 10.6mb ie under gassed etc,
and as long as the burner presure was set below this figure lets say 10.4, it would not really cause a problem , as you are styill getting the right amount of gas and if when gas rated was still okay.(okay would be classified as ncs). but it could still be operating correctly.

To be honest if the inlet pressure was as low as 10.6mb the appliance would be hugely undergassed going through a multi function gas valve.
If the inlet pressure was undergassed say for arguments sake 16mb and the appliance burner pressure was ok and everything else was operating within tolerances. then its your call but NCS should be called on the pipework as a minimum with a very strong recomendation to change ASAP... if you decided to make it AR no one would argue with you.

gb-gas

 

[GrahamM]

Re: if burner pressure is adequate, with only 1 appliance on circuit.any problems for

A range rated appliance MUST be able to meet the Max BP stated by the manufacturer. If the appliance is set on a medium rating you have to adjust regulator to maximum level to test BP, Gas Rate. Then regulate back to its original settings.
If the appliance does not meet the MI's max burner pressure then it is At Risk wither it is within the limits on its medium setting or not.