By Symptom
Problems We Solve
Most comfort issues start with one challenge: HVAC equipment is selected for peak conditions, but operates at part load the majority of the time. Standard compressors can only run at full capacity or shut off. APR Control acts like a dimmer switch, reducing capacity when the space needs less cooling to help improve comfort, humidity, and reliability issues.
High Humidity
Short cycling never runs the coil long enough to dry the air. Modulating keeps it pulling moisture out.
Humidity ControlDesign-Day Sizing Challenges
Equipment sized for the hottest day of the year is oversized 90%+ of the time, so it short cycles. APR Control runs it at part load instead of on and off.
Oversized HVACHigh Energy Bills
Running at full capacity then shutting off wastes energy. Modulating draws less compressor power at part load.
Energy EfficiencyFrozen Coils & Liquid Slugging
Oversized units and low airflow both freeze coils and slug the compressor. Built-in freeze protection keeps them safe.
Freeze ProtectionImprecise Discharge Air
When a space needs a tight, steady supply-air temperature, on/off cooling can't hold it. The APR‑E Valve holds discharge air to about ±1°F.
APR‑E ValveRepeat Compressor Failures
Short cycling wears compressors out early. APR Control avoids the cycling that causes it, while addressing the root issue of why the system cycles in the first place.
HVAC System ReliabilityNot sure which one fits?
One root cause behind all of them
Your equipment is sized for the hottest day of the year.
Because it is sized for design-day conditions, standard single-stage equipment is oversized 90%+ of the time. Without modulation it can only cycle on and off: it satisfies the thermostat quickly, shuts down, and starts again a few minutes later. That short cycling is what drives every problem on this page, from the humidity to the compressor wear.
The APR Control is a suction pressure-activated mechanical valve that adds continuous capacity modulation to standard DX systems and heat pumps. It runs the compressor at part load instead of cycling it, with no impact on the unit's rated capacity during design day conditions. Fix the short cycling and the symptoms ease together.
Tell us which problem brought you here.
Describe your equipment and what it is doing. A Rawal Devices Engineer will tell you honestly whether the APR Control fits, with sizing on us and a one-business-day response.
Get Expert Help[email protected] · 800‑727‑6447 · rawal.com