House repairs: What is this ?

[David]

Hello:
Ive been playing catch-up on repairs to a house I inherited. Does anyone know what this is or what it does?

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Thanks for any ideas you may have.

-David

 

[3moons]

Water heater pressure relief valve to outside vent?

 

[adawil2002]

That is for natural gas or LPG (liquid propane gas). It's called a "drip leg", there are 2 types. Think of it as a shock absorber for hot water heaters & hot water tanks, it prevents or lessens water hammer.

The other allows any gas moisture a place to drip & widely used in steam heat systems.

 

[David]

Thanks guys.