Will POL Fitting Allow Air to Enter Propane Hose When Disconnected
Updated 12/29/2025 | Published 12/07/2025
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Question:
I am looking at installing 103613-MBS along with 100794-120-MBS on my RV’s propane system to attach an extra 100lb tank this winter. One thing I am concerned about is the flow of propane when I go to disconnect my 100lb tank for refills. When I shut off the QD and unscrew the POL fitting from the tank will the hose let the existing propane escape and fill with air? Even if the QD is still attached but turned off? My RV furnace has a problem with working when there’s any amount of air in the propane system and I’d like to not worry about the hose filling with air this winter. Or is there a valve I can put between the male POL on the hose and female POL fitting on the tank?
asked by: Austin D
Expert Reply:
Hi Austin; the T-Fitting # 103613-MBS and Propane Adapter Hose # 100794-120-MBS will work for this setup. However, the POL fittings do not have check valves so it is possible for air to enter the hose when you disconnect it.
You will have to get some kind of adapter with a check valve to prevent that from happening. These do exist but unfortunately, that is not something that we carry. You can typically prevent air lock issues by turning the propane on very slowly, and allowing the pressure to equalize before you run anything like your furnace.
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Product Page this Question was Asked From
MB Sturgis Sturgi-Stay T-Fitting - Type 1 Valve - Quick Disconnect and Disposable Cylinder Ports
- Propane Fittings
- Tees
- Type 1 - Female
- 1 Inch-20 - Male
- Type 1 - Male
- MB Sturgis
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Robin H.
12/29/2025
Hey Austin, were you able to find an adapter with a check valve to keep air from entering your propane hose? Knowing what worked could help others trying to connect an extra tank for winter use.