zero governor

[stokecity]

hey guys, if a boiler has a zero governor does it still have a venturi or are they the same thing?? sorry for the school boy question, thanks

 

[Leo21]

Why on earth would you want to know that?

 

[stokecity]

trying to get an understanding of boilers, its my understanding that zero governors are on band A boilers and venturi were on boilers before band A's????

 

[mountainman]

Dunno really. But a Venturi is used in a water section containing a diaphragm and push rod to either directly operate a gas valve or a microswitch.
Times seem to have moved on from them to flow switches.
Is there a specific reason for your question?

 

[mountainman]

Ah! Enlightenment.
Venturi's were used in gas water heaters.
See if you can find a drawing for a differential pressure valve and you should find one.
I still remember drawing them from my college days.

 

[stokecity]

no specific reason mountainman, did my acs a few weeks ago and when i did my gas foundation we covered loads on zero governors but cant remember anything about venturi, and the info i can find on the net seems to describe them as doing the same job as the governor

 

[dancinplumba]

venturi's are found in the flues of older boilers, they operate the aps, they are also found in band 'a' boilers where the air from the fan blows across it and sucks gas into burner, the faster the fan, the more gas is sucked in
imo

 

[mountainman]

A Venturi is nothing like a governor.
It is more like an injector in a gas cooker burner.
Pass gas or water through a restriction into a lower pressure area then there will be a negative pressure effect that will either entrain primary air into a burner or allow a diaphragm valve to lift.

 

[stokecity]

A Venturi is nothing like a governor.
It is more like an injector in a gas cooker burner.
Pass gas or water through a restriction into a lower pressure area then there will be a negative pressure effect that will either entrain primary air into a burner or allow a diaphragm valve to lift.

isnt this the same as zero governor?? execpt its the fan that creates the negative pressure?

 

[mountainman]

I guess that you are correct.