unions on gas lines

theprentice

i'm just curious, I have seen numerous threads indicating that unions are illegal on gas lines. I asked my master plumber boss/employer, and he said that it would be near impossible to succesfully install a gas system without them. I know that on every boiler boiler, water heater, and appliance I have installed that is gas supplied i have used a union. I guess that I'm just confused, if someone could clarify I would appreciate it.

thanks.

[Deleted User]

Key word...

CONCEALED union. In other words, you can not have a union mid pipe in a run that could eventually be covered by a sheetrock ceiling.

They are required at the appliance termination, except for the gas meter, where you are supposed to use a left right nipple/coupling on the house side of the meter. At least here in Denver, such is the case.

ME

theprentice

thanks mark,
that makes sense now, I am in Colorado as well (western slope) nice to know, I guess that you learn something everyday, that's why I love this trade

Weezbo

the devils in the details:)

Mark,if you see a post on controling some circs with variable speed...got a min?

ScottMP

You may be confusing

Dielectric Unions with a standard appplaince union.

Dielectric unions are used to seperate ferrous materials from non-ferrous, ie; Iron piping from copper. Many here disagree in thier use on a heating system. I don't use them, others do. They contane a rubber gasket that seperates to the two sides of the union to produce a barrier between dissimilar metals.

You are correct that a standard ground joint union is neccesary for all connections for gas applainces.

Scott



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