Originally Posted by
whizbang102000
Howdy,
The reason for a two stage regulator is due to the high pressure from the mains out in the road. This needs to be dropped down to a suitable pressure to suit your appliances.
If the pressure is too high you will use more gas than necessary and your appliances will only be rated for a certain pressure.
The two stage regulator will reduce the first stage of pressure and then the second stage. You will find that the spring required to reduce the pressure will only drop it a certain amount and hence the need for a second stage or spring suitable for the last stage.
Example:
Inlet pressure from mains may be 1200kpa and your appliance only needs 300kpa. The first stage will drop it from 1200kpa to 700kpa and the second stage from 700kpa to 300kpa.
For peace of mind it may be worth checking with your local gas authority on what the gas pressure is into your meter so you get a better understanding of what the plumber is saying.
Good Luck