The Two-pipe Takeover

For any commercial application, two-pipe Variable Refrigerant Flow (VRF) zoning systems – like that from Mitsubishi Electric Cooling & Heating (Mitsubishi Electric) – provide a solution that leaves three-pipe systems struggling to keep up. Proven in the field, two-pipe technology is not only more economical to install but reliable, energy-efficient and able to provide superior levels of control and comfort for occupants.

If you’re still designing and/or installing three-pipe systems, here are a few reasons why we here at the Advanced Products Group (APG), a division of Aireco Supply, Inc., have chosen to move toward two-pipe, and why you should consider making the move to two-pipe.



Electrical Connections
Two-pipe VRF has significantly fewer electrical termination points than three-pipe systems. Having fewer electrical connection sites reduces the complexity of the wiring process will reduce any potential connectivity issues. Ultimately, fewer components in the system means less chance of the system failing in the future.


Two-pipe architecture allows the indoor units to change temperature quickly from cooling to heating, or heating to cooling. The cooler/hotter refrigerant from one indoor unit moves to the branch controller and gets redistributed right there to another indoor unit. In a three-pipe system, the redistribution happens out in the condenser, not locally in the branch controller. Since a three-pipe system’s refrigerant has to be moved farther to undergo the same redistribution process, the system responds more slowly, loses energy along the way and costs more money to operate. 

Future Servicing, Alteration Ease
A VRF system with a two-pipe design makes future servicing simpler, increasing lifetime cost savings. Plus if additions are needed in the future, the new components can be engineered and added while the system remains in operation.


In comparison to the complexity of a three-pipe system, the streamlined two-pipe offers more design capabilities, an easier installation and project cost savings. As El-Abd said, “For any commercial project, you can reduce significantly the amount of damage to a building with a two-pipe system. A two-pipe system will also save money because you don’t have to spend on a third pipe or extra branch controller boxes.”