Used Thermo King V-520 RT MAX Power Unit

The Thermo King MD-200 is a refrigeration unit made for medium-sized delivery trucks, like those 12 to 20 feet long, used to keep food, flowers, or medicines cold or frozen during transport. It’s part of Thermo King’s MD (Medium Duty) series, built by a company famous for refrigeration since the 1930s. The MD-200 is perfect for local or regional deliveries—think grocery runs or catering—not big trailers crossing the country. It’s tough, reliable, and still popular in 2025, especially for truck owners who want something affordable and easy to fix.

This unit runs on a small diesel engine, the Yanmar TK370, which puts out about 19 horsepower—enough to cool a truck without guzzling fuel. It uses R-404A refrigerant to chill the air, powered by a Thermo King X214 compressor that’s simple and sturdy. You can set the temperature anywhere from -20°F (super cold for frozen stuff) to 80°F (warm enough for fresh goods). It cools fast—around 10,000 BTU per hour at 35°F, or 6,000 BTU at 0°F—and can heat up to 6,000 BTU to protect cargo in winter. Fans inside push about 1,500-2,000 cubic feet of air per minute, keeping the whole truck evenly cold.

The MD-200 comes in two versions: the MD-200 30 (diesel only) and the MD-200 50 (diesel plus electric standby). With electric standby, you can plug it into a power outlet (230V or 460V) when parked, saving fuel and making it quieter—great for city rules against idling. A control box, usually the Thermoguard or a fancier SR-2/SR-3 screen, lets the driver pick the temperature and check if everything’s working. Features like CYCLE-SENTRY turn the engine off when it’s cold enough, cutting fuel use by up to half (0.5-1 gallon per hour).

It’s built tough with a lightweight plastic shell that doesn’t rust, sized at about 60 inches wide, 24 inches deep, and 30 inches tall, weighing 800-1,000 pounds. The engine and parts are easy to reach for repairs, and Thermo King has over 200 dealers worldwide for support. It’s not super quiet—around 65-70 decibels on diesel, 55-60 on electric—but you can add a noise kit to hush it up.Buy Thermo King MD-200 Online