The 12-24V supply model of the N321S is a controller originally intended for solar water heating applications, harnessing renewable energy by controlling liquid or air circulation based on the temperature difference between two supplied NTC sensors (included). In a solar application, the control output activates the water circulation pump to maintain an even temperature between the solar collector and storage tank — useful for swimming pools, hot tubs, and hot water recycling systems. For air destratification/circulation, the control output activates a high-level fan to keep an even temperature throughout a building's layers, eliminating heat wasted at the top of warehouses, factories, or agricultural buildings. It's also used to cool grain stores and maintain the correct differential. As part of a solar system it also provides protection against overheating and freezing to the piping, preventing damage to the system.
The N321S is also available as a 100-240V supply model or with optional RS485 communications.
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Novus N321-S Datasheet Download
Technical Details
NTC Thermistor: 10 kΩ @ 25°C, range: -30 to +105°C (-22 to 221°F), Accuracy: 0.6°C (1.1°F)
Sensor interchangeability: 0.75°C (1.35°F). Measurement Resolution: 0.1° from -19.9 to 119.9°
Output: Relay SPDT, 1 HP 250 Vac / 1/3 HP 125 Vac (16 A Resistive)
POWER SUPPLY: 12 to 30 Vdc/ac. Mains Frequency: 50~60 Hz. Power Consumption: 5 VA
Dimensions: 75 x 33 x 75 mm. Weight: 100 g. Panel: 70 x 29 mm
Frequently Asked Questions
Do I need to buy sensors separately?
No — the N321S is supplied complete with 2 NTC temperature sensors ready for solar collector/tank or dual-point differential use.
What's the difference between this and the mains model?
Only the supply voltage — this 12-24V version suits control-panel or off-grid installations; the 100-240V model suits mains-powered sites. Both are also available with optional RS485 communications.
Can this protect against freezing as well as overheating?
Yes — as part of a solar system it provides protection against both overheating and freezing to the piping.
Industry Applications
- Solar Water Heating — maintains even temperature between collector and storage tank, protecting against overheat and freeze.
- Building Air Destratification — activates high-level fans to redistribute trapped heat in warehouses and agricultural buildings.
- Grain Store Cooling — maintains correct temperature differential for stored grain.