Will POL Fitting Allow Air to Enter Propane Hose When Disconnected
Updated 12/29/2025 | Published 12/07/2025
Products Featured in This Question
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.
(click to enlarge)
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
more information >
Continue Researching
- Article: What are the Common Types of Propane Fittings Used on RVs?
- Q&A: Adding 100 lb Propane Tank to 5th Wheel with Dual 30 lb Tanks with Auto Changeover Regulator
- Q&A: Tee and Hose for Quick-Disconnecting Grill with 1 lb Propane Fitting
- Article: 2 Steps for Hooking Up an External Propane Tank to Your RV
- Q&A: Parts Needed to Connect Auxiliary 20 lb Propane Tank to Dual Onboard Camper Tanks
- Article: How (and Where) to Connect an RV Propane Grill
- Q&A: Can A Third Tank Be Added To A Propane Tank Setup With An Automatic Changeover Regulator
- Q&A: Connecting Champion 4500 Dual Fuel Generator to Travel Trailers Propane System
- Q&A: How to Add Extra RV Propane Connections for Gas Grill and Fish Cooker
- Q&A: Comparing Colors of ACME Type 1 Propane Connectors for Function
- Article: Anti-Rattle Devices
- Article: How to Measure for Trailer Hitch Drop
- Article: Our Team Picked The Best Camping Gear of the Year - Here Are Their Top Choices
- Article: Stability Control for Heavy Duty Vehicles
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.