Engineer Resource Center
Engineer Resource Center
Protect your spec: start specifying the APR Control, an external compressor unloader that adds continuous capacity modulation, on your project to improve system performance when operating outside of design day conditions. The links below give you submittal-ready specs, selection guidance, and the research behind every claim.
Value engineering, done right
Variable-capacity part-load modulation, at a fraction of the cost of variable speed
Specify the APR Control to give standard DX equipment the part-load capacity modulation of variable speed or digital scroll compressors, without their cost, complexity, or added failure points.
Bullet-proof your specification without compromising the budget
Specify standard single-stage equipment with the APR Control and you meet the modulating-performance requirement without the first-cost premium of variable-capacity units.
Spec & Submittal Center
Spec sheets and dimensional data for each refrigerant, plus the matching submittal-ready installation packages.
Sizing & Application Guidance
APR Control is sized to the lead compressor, ensuring proper oil entrainment and circuit configuration, across the full application range. Send us the equipment and we do the selection.
Research & Evidence
Independent field study (77% fewer compressor starts, zero failures), manufacturer lab testing (16% lower part-load power), and RP-1604 cleanroom research. Every figure carries its qualifier.
Engineer Consultation
The same expert help, framed for design-stage collaboration. Bring us in early and spec APR Control correctly the first time.
Or start by what you need
“By utilizing the APR‑E Valve modulating technology on a single stage, constant speed compressor, integrated and programmed into our BMS controls, we were able to maintain a deviation from setpoint of no more than +/- 1°F.”
Wei Sun, P.E., President, Engsysco · ASHRAE cleanroom research project
Specifying APR Control on a project?
Bring a Rawal Devices Engineer into the design conversation.
Get Expert Help[email protected] · 800‑727‑6447 · rawal.com