Flame King ACR-2a two-stage automatic changeover propane regulator for RVs — 345,200 BTU, inverted-flare inlets

Flame King ACR-2a is a two-stage automatic changeover propane regulator that keeps your RV, van, or trailer supplied with fuel by switching to a full tank when the primary bottle runs out.

This compact regulator is built for mobile life: it automatically transfers propane flow from the empty cylinder to the reserve tank, maintains steady delivery under varying loads, and meets UL safety standards for reliable performance. Designed for use with dual-tank RV systems, the ACR-2a accepts 1/4" SAE inverted flare inlets and provides a 3/8" NPT female outlet, delivering up to 345,200 BTU while holding factory-set pressure levels for consistent appliance operation.

How does the automatic changeover work when a tank runs dry?

The ACR-2a monitors the primary cylinder and flips to the reserve immediately after the main tank reaches its lockout point. The changeover happens without manual intervention, so heating, cooking, and refrigeration continue uninterrupted while you swap or refill the empty cylinder.

• Automatic transfer to reserve tank at lockout pressure up to 14.9" WC
• Primary tank removal allowed without stopping gas supply
• Clear inlet fittings for inverted flare connection to standard pigtails
• Factory-calibrated so no field adjustments are necessary

Will this regulator keep gas pressure steady during heavy RV appliance use?

Yes — the two-stage design minimizes pressure swings as appliances cycle on and off. That double-stage regulation helps provide consistent output so burners, furnaces, and refrigerators run more smoothly compared with single-stage alternatives.

• Two-stage design maintains steady delivery under changing demand
• Factory set to 11" WC with stable regulation across loads
• Rated capacity up to 345,200 BTU for high-demand setups
• Built-in safety lockout prevents supply from an empty tank

What connections and accessories are compatible with this regulator?

The unit features 1/4" SAE inverted flare inlets and a 3/8" NPT female outlet, matching common RV plumbing. Flame King recommends specific hoses and inverted-flare pigtails for reliable fit and performance; NPT pigtails are not advised for this regulator.

• Inlet: 1/4" SAE inverted flare (two inlets for two cylinders)
• Outlet: 3/8" NPT female pipe thread to downstream line
• Compatible hoses: Flame King 48" Thermo Plastic Hose (100383-48)
• Recommended pigtails: 12–18" inverted flare models E12INPT, E15INPT, E18INPT

How is safety and leak prevention handled on this regulator?

Flame King assembles the regulator with high-strength thread-locker on adapter connections to keep fittings secure and reduce leak risk. The product is UL listed and engineered to industry connection standards, but correct installation and periodic inspection remain important for safe operation.

• High-strength thread-locker (Loctite) applied to critical adapter threads
• UL listed components and standardized inlet/outlet fittings
• Installer should follow manufacturer instructions and inspect seals regularly
• Not designed for use with NPT pigtails — use inverted flare pigtails

Who this is for: The Flame King ACR-2a is ideal for RV owners, van-lifers, and trailer users who run dual-cylinder propane systems and want uninterrupted fuel supply and steadier appliance performance. It's for people who prefer a factory-set, UL-listed regulator that pairs with common inverted-flare pigtails and flexible hoses for a reliable, low-maintenance installation.