Flame King ACR-2 Auto Changeover Propane Regulator Without Pigtails — 2-Stage Low-Pressure for RVs

Flame King ACR-2 is a two-stage automatic changeover propane regulator that keeps gas flowing from a reserve tank while you swap an empty cylinder, designed for RVs, trailers and vans.

This regulator is built for dual-tank propane systems on mobile homes and recreational vehicles, switching seamlessly from the primary cylinder to the backup when pressure drops. It is UL listed, factory set to a stable low-pressure output, and engineered to preserve constant delivery under varying demand. The ACR-2 ships without pigtails so you can choose the correct hose length and fitting for your installation.

How does the regulator switch between tanks?

The ACR-2 senses pressure loss from the primary tank and automatically opens the reserve side so appliances continue running without interruption. No manual valve changeover is required, making refills more convenient while you travel.

• Automatic changeover activates when primary tank pressure falls to lockout threshold.
• Two-stage design keeps outlet pressure stable during the switch.
• Allows removal and refill of the empty cylinder without shutting off gas supply.

What pressure and connection types does it use?

This model is factory set to deliver low pressure suitable for typical RV appliances, with a rated capacity that handles high combined BTU loads. Inlet and outlet threads follow common RV standards, but it arrives without pigtails so you can match your vehicle’s hose lengths and fittings.

• Factory set outlet: 11 inches water column (approx. low-pressure setting).
• Lockout pressure up to 14.9 inches WC; rated throughput up to 345,200 BTU.
• Inlets: 1/4" SAE inverted flare. Outlet: 3/8" NPT female pipe thread.

Why choose a two-stage regulator instead of a single-stage?

Two-stage regulators reduce pressure fluctuations when demand changes, so burners and appliances get a steadier flow and are less likely to soot or starve during heavy use. This improves performance when multiple appliances run at once or when ambient temperature affects cylinder pressure.

• First stage drops bulk tank pressure; second stage fine-tunes to appliance-ready output.
• Improved stability under varying loads and weather conditions.
• Factory calibration reduces the need for field adjustments.

How do I install and which hoses work best?

The regulator is compatible with Flame King inverted-flare pigtails and a recommended thermo plastic hose for flexible routing. It’s assembled with thread-locker on adapter connections to keep fittings secure and prevent leaks, so follow torque and sealing guidance during installation.

• Compatible with Flame King 48-inch Thermo Plastic Hose (model 100383-48).
• Works with 12–18 inch inverted flare pigtails (models E12INPT, E15INPT, E18INPT).
• Note: NPT-style pigtails are not recommended; regulator arrives without pigtails so you can select proper lengths.

Who is this for? The Flame King ACR-2 is intended for RV owners, vanlifers, and trailer users who run dual-tank propane systems and want uninterrupted gas for cooking, heating, and hot water while swapping cylinders. It suits installers and DIYers who prefer to select their own hose lengths and fittings, and anyone who needs a UL-listed, two-stage regulator rated for high BTU demands and consistent low-pressure output.