Unions/ Inside Furnace Cabinet

[stlguy]

Are unions ever allowed inside a furnace cabinet? If not why are T fittings allowed by not unions?

[timebuilder]

An interesting question. Maybe someone with a copy of the fuel gas code will post.

My guess is that the manufacturer can DESIGN the use of a union in the cabinet. I see that in large York gas packs with more than one row of burners.

[hvacvegas]

Interestingly enough, the word "union" isn't found in the internation fuel gas code 2009.

I've been told by inspectors, that a union cann't be inside of a vestibule, ever.

Of course, that may be local code.

http://publicecodes.citation.com/ico...-P-2009-000019

[the dangling wrangler]

Just a guess.

A union could possibly come loose, and leak.

[hvacvegas]

Just a guess.

A union could possibly come loose, and leak.

Right, but then the question is, whats safer? A union leaking inside of an induced draft compartment, where the inducer would pull leaked gas out on startup. Or it being in the house?

You might not notice the gas leak in the house because of the inducer pulling it out though, or it being pulled out via natural draft. This would be bad.

Also, the leak igniting outside of the combustion chamber, but inside the vestible, ruining the wiring.