Danfoss EKS 65 084H3020 Electronic Expansion Valve Controller

Danfoss EKS 65 Electronic Expansion Valve Controller (MPN: 084H3020)

The Danfoss EKS 65 (Code No. 084H3020) is an industrial-grade, electronic PI (Proportional-Integral) superheat regulator designed for dry evaporation refrigeration systems. Built inside a rugged die-cast Silumin casing, this controller modulates electronic expansion valves (such as the Danfoss TQ and PHTQ series) by continuously measuring evaporator temperature differentials and pressure conditions.

Key Features

1. Proportional-Integral (PI) Modulation: Dynamically adjusts valve opening based on real-time superheat calculations maximizing heat transfer efficiency while preventing liquid floodback.
2. Dedicated MOP (Maximum Operating Pressure) Limiter: Built-in adjustable regulator (0 to 6 bar) protects the compressor drive motor against suction pressure overload during startup and defrost recovery.
3. Multi-Refrigerant Selector Switch: Onboard DIP-switch allows configuration for R22, R134a, R404A, R507, and alternative fluorinated refrigerants.
4. Silumin Die-Cast Marine Casing: Heavy-duty enclosure rated IP54 ensures vibration resistance, EMI shielding, and corrosion resistance against saline marine atmospheres.
5. Integrated Forced Override Logic: Terminals allow forced opening (full injection), forced closing (tight shut-off), and standby warm-up modes for automated defrost sequences.

Compatible Actuators & Valves

• Direct-Operated Valves: Danfoss TQ 20, TQE 20
• Servo-Operated Valves: Danfoss PHTQ series (PHTQ 85, PHTQ 125, PHTQ 300)
• Sensors: Danfoss AKS 21A surface mount Pt1000 sensor, AKS 21W immersion temperature sensor

Part Number Cross-References

• 084H3020 – EKS 65 complete controller unit
• 084H3025 – EKS 65 mounting enclosure / bracket base
• 084H3021 / 084H3022 – EKS 65 regional/sub-variant references
• Replaces legacy Danfoss EKS 61 / EKS 67 series in retrofitted TQ evaporator control circuits

Industrial & Marine Applications

• Marine Provision Refrigeration Plants: Cold room evaporators (meat, fish, vegetable, and dairy handling rooms).
• Cargo Hold Refrigeration (Reefer Ships): Evaporator direct-expansion control in multi-deck cargo holds.
• Chilled Water Plants & AC Chillers: Dry expansion shell-and-tube liquid chillers for accommodation HVAC.
• Industrial Blast Freezers & Spiral Freezers: Quick-response superheat optimization during sudden thermal load changes.

Frequently Asked Questions

What is the function of the Danfoss EKS 65 084H3020?

The EKS 65 is an electronic superheat controller that regulates the injection of liquid refrigerant into dry evaporators by sending modulated voltage signals to Danfoss TQ/PHTQ expansion valves.

What supply voltage does the EKS 65 require?

It operates on 24 V AC ±10% , 50/60 Hz. A dedicated Class II step-down transformer rated for at least 80 VA must be used when powering both the controller and the thermo-electric valve actuator.

How do I test if the controller is outputting the correct superheat measurement?

Measure DC voltage across terminals 26 (-) and 29 (+) using a standard multimeter. The scaling is 100 mV per 1° C of measured superheat differential.

Can the EKS 65 be used with newer refrigerants like R134a and R404A?

Yes. The controller has an internal refrigerant selector DIP switch that can be set for R22, R134a, R404A, and R507.

What happens if terminal 1 and terminal 61 are shorted?

Bridging terminals 1 and 61 activates forced closing mode, completely cutting electrical power to the TQ valve heating actuator to shut off refrigerant feed immediately.