working pressure

[rm1]

if you have a working pressure of 18mb at the appliance and the burner pressure at the appliance is less than the recorded working pressure this is classed as "NCS" (ie) 19mb at meter and 1mb pressure loss on system=18mb wp, bp on appliance max 12mb this is fine on a SE boiler, however when you change the appliance to a high efficiency boiler which has a zero governor as there is no set bp and the volume of gas used is dependent on the fan speed and the mi say 20 mb at appliance would this then be classed as "at risk"

 

[Spanner2k7]

hi rm1,
burner pressure is different from working pressure, you may get a correct working pressure, and the burner pressure can be as low as 9mb.

In my understanding. The only time working pressure is a problem is when burner pressure cannot be maintained.
If you have low working pressure, but burner pressure is ok, and no other appliances are effected it can be classed as NCS, however if the other appliances are effected the it is classed as AR

 

[rm1]

hi spanner i am fully aware of what wp and bp is

 

[stevetheplumber]

18mb inlet and 12mb burner is fine if 12mb is the max bp that the boiler works at ,fitting a zero govenor boiler which mi's state 18mb is also fine

some old vailants run bp,s of as low as 4.5

 

[smillsey]

rm1,

what are you actually asking? Or was the thread a statement?

 

[rm1]

verification

 

[smillsey]

Well you check zero governor boilers by gas rate, flue gas, and MI's for what they will accept for the lowest working inlet pressure...

Why would you class it as at risk? Explain this

Do you have ACS?

What would you suggest undergassing would cause? In the short term and long term, if you understand this you will then be able to make an informed decision on an undergassed category (NCS, ID, AR )

 

[smillsey]

Dont worry about the "Procedure to follow" when categorising, it will make you blind to what is actually going on.

Establish the Effect the "problem" will cause, then worry about the Unsafe sits procedure....

 

[fuzzy]

if you have a working pressure of 18mb at the appliance and the burner pressure at the appliance is less than the recorded working pressure this is classed as "NCS" (ie) 19mb at meter and 1mb pressure loss on system=18mb wp, bp on appliance max 12mb this is fine on a SE boiler, however when you change the appliance to a high efficiency boiler which has a zero governor as there is no set bp and the volume of gas used is dependent on the fan speed and the mi say 20 mb at appliance would this then be classed as "at risk"

worth noting that the presuure loss across the system doesnt have to be 1mb, thats the maximum drop