The Castair RDDH is a heater accessory for Castair refrigerated compressed air dryers. The H suffix in this part number indicates a heater component — specifically, a low-ambient temperature heater kit used to protect refrigerated dryers operating in cold shop environments. Castair refrigerated dryers are designed for indoor operation in ambient temperatures that support proper refrigeration cycle performance. When a dryer is installed in an unheated area, garage, or facility where ambient temperatures can drop near or below freezing, the refrigerant circuit, heat exchanger, and automatic drain are at risk of freeze damage and reduced efficiency.
A low-ambient heater kit on the RDD series dryer prevents condensate in the drain circuit from freezing, protects the refrigerant system from operating outside its rated temperature range, and maintains consistent dew point performance in cold-weather shop environments. If your dryer is installed in an unheated bay, near an exterior wall, or in a space that sees freezing temperatures in winter, this heater accessory is a worthwhile investment over the cost of a freeze-damaged dryer.
Why Low-Ambient Heat Protection Matters
- Drain freeze prevention: The automatic demand drain ejects liquid condensate. In sub-freezing ambient conditions, that condensate can freeze in the drain valve or drain line before it clears the unit — causing drain blockage and moisture bypass.
- Refrigerant circuit protection: Refrigeration compressors have minimum ambient operating temperatures. Operating below this threshold increases refrigerant pressure ratio and can cause compressor damage over time.
- Consistent dew point performance: Cold ambient temperatures affect heat exchanger performance. A heater maintains the dryer in its designed operating temperature range year-round.
Compatible Equipment
- Castair RDD series refrigerated compressed air dryers (RDD40, RDD50, RDD80 series)
- Confirm compatibility with your specific RDD model by calling 866-217-0063 before ordering
What's in the Box
- Castair RDDH low-ambient heater kit for RDD series refrigerated dryer
Installation details, electrical specifications, and wiring requirements available by contacting us. This is a field-installed accessory.
Technical Specifications
- Part Number: RDDH
- Manufacturer: Castair (Cast Air, Inc.)
- Application: Castair RDD series refrigerated compressed air dryers
- Component type: Low-ambient temperature heater kit
- Electrical specifications: Contact us for voltage, wattage, and wiring details — 866-217-0063
Why Buy From Air Compressor Factory Direct?
We specialize in Castair compressed air equipment and accessories. If you are unsure whether your dryer installation requires the RDDH heater kit, call us — we can walk through your shop conditions and confirm whether the heater is needed and how to install it properly. Free shipping on qualifying orders, free pre-sale technical support, genuine Castair parts.
Call 866-217-0063 for quick answers and help!
