• Founder Davis I. Rawal (1921-2006) with “Winston”

Welcome to Rawal Devices

Davis Rawal said “Let there be modulation” and it was good!

Davis Rawal, inventor of the Rawal Device, was one of those creative engineers who could uncover cost-effective solutions to unusual problems. Rawal’s ingenuity ranged from inventions that resulted in patents (a very early air-to-air heat exchanger) to solutions that provided an edge in winning and completing a competitive project (a severely space-constrained DX evaporator air handling unit).

Part-load control that’s better than hot gas bypass

This creativity resulted in the development of the APR Control, also known as the Rawal valve. Davis was consulting on a project where an engineer specified standard hot-gas bypass to the evaporator coil. The design required multiple large-capacity split systems with evaporators located a considerable distance from the condensers. Realizing that the hot gas would condense prior to arriving at the evaporator coil, Davis sought another solution. After the successful application of this unique solution, he recognized that it could be applied to a variety of needs for part load control. He simplified and engineered the device down to its compact size and patented it as the APR® Control.

Davis recognized that the APR Control’s unique design provided advantages such as lower installed cost – especially on split-system applications – and much smoother response to system and load changes. He envisioned additional opportunities and applications for the device.

New generation leads Rawal Devices for next-gen HVAC control

Since 1993, the APR Control has been applied to temperature- and humidity-sensitive spaces that would normally require considerably more costly solutions. Guided for the last 20 years by Davis’ son Richard, Rawal Devices has sold tens of thousands of APR Controls, providing system solutions to thousands of engineers, facility managers, and service contractors across the country and around the world.

Note: APR Control and APR-E Valve are registered trademarks of Rawal Devices, Inc.

Meet the Team

Richard Rawal

Richard Rawal


From the age of 14, Richard learned the HVAC business in the family contracting firm. He attended engineering school and invested years in design-build contracting and service support along with his father, Davis.

They started Rawal Devices in 1993 following successful patent of the APR Control. For over twenty years Richard has built the APR Control distribution process and created relationships with major OEMs, contractors and engineers across the country.

Rawal Devices customers have always been his focus, and the APR Control has proven its effectiveness in delivering leading-edge control performance for building technologies.

Jason Santos

Jason Santos

Senior Technical Engineer

Jason started in the HVAC industry at the age of 13, going on service calls with his father. After graduating from technical college he worked in the field for more than 30 years as a Service Technician, Service Manager and in start-up commissioning. Jason’s experience ranges from a limited tenure in the residential field to vast experience in the bio-medical field with an expertise in all aspect of DX equipment including chillers, VAV, VVT, Make-Up Air, and more. Towards his lasts days in the field, he was performing HVAC Forensic Analysis for large commercial /industrial spaces. He was instrumental in resolving issues from design issues to systemic automated control issues, as well as fundamental mechanical flaws. Jason joined Rawal Devices in 2017 as Senior Technical Engineer. Since joining the team, Jason has provided a wide range of training to both employees and service customers, took the lead on various research and development projects, and has been fundamental component of the APR-E project in both development and application.

David Larocque

David Larocque

Sales Engineer

After receiving his degree in Mechanical Engineering, David spent a few years working at Cambridgeport Air Systems, designing rooftop curbs and economizers. Looking to transition into more of a sales role, David joined Rawal Devices in 2018 as a Sales Engineer. As a quick learner and with a personable manner, David serves to educate customers and grow our industry reach, building upon his existing strong relationships.