Propane gas regulator creating bottleneck?

[vegasbuchanan]

I have propane service and I'm going to replace all my lines after the secondary regulator. My question is the outlet on the regulator is 1/2 inch with an elbow that expands to 3/4, let's say my calculations required a 1 inch pipe from the regulator on, wouldn't this create a bottleneck at the outlet of the reg? I was under the impression you could not go smaller to larger in fittings or pipe size without a decrease in flow? My propane company's technician said it was not a problem is he right?

 

[vegasbuchanan]

Here is a photo

 

[Sponsor]

 

[Reach4]

is he right?

Yes.

 

[Jadnashua]

The pressure behind your regulator is presumably considerably higher than that after the regulator, so, when needed, the regulator will end up opening to keep the outlet pressure up, at least until it reaches its design maximum. But, there is a limit on how much gas a particular sized line can handle that depends on the effective length (which is not just the actual length), which gets longer as the flow increases, or, the more changes of direction it takes. There are gas flow tables you can look up that will tell you how many BTUs would be supported on a particular sized line and the effective length. You might be fine, you might not.