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50 Years of Innovation

See us at the
2019 AHR Expo
Jan. 14-16, 2019
Atlanta

See us at the WEEC
2018 World Energy Engineering Congress
Oct. 17-19, 2018
Charlotte, NC

  • For walk-in and reach-in coolers and freezers
  • Continuously variable evaporator fan speed automatic control
  • Maximum efficiency, reduced compressor run time, improved product shelf life
  • PWM and DC outputs
  • Multi-Motor Capable
  • Compatible with all variable speed EC motors (ECM)
  • This is a retrofit. Replace your fan (if needed) and the fan control input with the 759 and save energy. All necessary items supplied by Hoffman Control.
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Time      Core     Vault    Fan Speed
1920      31.0      34.6       21
1940      31.0      34.8       24
1960      31.0      34.8       24
1980      31.6      35.0       27
2000      32.0      35.3       31
2020      32.8      35.5       34
2040      34.4      35.7       37
2060      34.8      36.1       42 
2080      35.3      36.3       45
2100      35.5      36.5       48
2120      35.7      36.5       48
2140      36.1      36.7       50
2160      36.3      36.7       50
2180      36.5      36.9       53
2200      36.7      37.2       57 
2220      36.7      37.4       60
2240      36.9      37.4       60
2260      36.9      37.6       63
2280      37.2      37.6       63
2300      37.2      37.6       63
2320      37.2      37.8       66
2340      37.4      37.8       66
2360      37.4      38.0       69
2380      31.6      37.8      254
2400      19.5      36.9      254
2420      16.0      35.5      254
2440      29.1      34.6       19
2460      30.8      34.4       19
2480      31.0      34.4       19
2500      31.0      34.6       19
2520      31.0      34.6       19
2540      31.0      34.8       20
2560      31.2      35.0       23
2580      31.6      35.3       28
2600      32.2      35.5       31
2620      33.2      35.7       34
2640      34.6      35.7       34
2660      35.0      36.1       40
2680      35.3      36.3       43
2700      35.7      36.5       46
2720      35.7      36.5       46
2740      36.1      36.7       49
2760      36.3      36.7       49
2780      36.5      36.9       52
2800      36.7      37.2       56
The chart above shows the average power consumption in Watts for a mid-temperature walk-in cooler as tested in our laboratory. This represents a 63% reduction in energy. Although other ECM environments demonstrate some reduction in energy compared to shaded pole motor evaporator fans, this controller has shown the most efficiency since it continuously optimizes the fan speed based on current operating conditions using an adaptive algorithm.
Other Featured Products

This electronic head pressure control modulates condenser fan motor speed thereby varying the air volume through the condenser. The control monitors the head pressure by sensing the sub-cooled liquid line temperature.

There are two temperature inputs and three outputs (PWM, 0-10 VDC and 10-0 VDC) to control the ECM or VFD variable speed fan motor.

Two temperature parameters can be set to optimize the range of fan speeds so that as the ambient temperature changes, the fan speed is varied in order to maintain the correct head pressure.

This improves system performance while saving energy and eliminating compressor slugging. The non-invasive temperature sensors require no system penetration.

If you need to control multiple motors, or have more or other input sensors, or have Modbus communication, we've got a product for that also.
  • Operate up to 12 stages of fans, compressors, or heaters
  • Continuous output variation possible with one variable unit added to the mix
  • MODBUS RTU communication with building automation systems
  • Up to six sensors for monitoring inputs with combining options
  • Menu system allows easy set point adjustment including hysteresis
  • Secondary set of set points can be used based on an input contact closure
  • 32 character LCD display
  • 12 relay outputs plus modulating output (PWM and 0-10 VDC or 10-0 VDC)
  • Inputs can be temperature, pressure, 0-10 VDC, or contact closures
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  • Protects single phase and 3 phase motors from current draw problems
  • Uses current transformers to digitally sense currents
  • Two temperature sensors can also be used for thermal monitoring
  • MODBUS RTU communication with building automation systems
  • Trip point can be set based on current flow, current imbalance, temperature
  • Current trip timing is based on energy into system after trip set point is reached
  • Menu system allows easy adjustment of parameters and set points
  • 32 character LCD display
  • Selectable number of trips with automatic reset
  • Alarm signal
  • Can read and write all values over MODBUS, including manual reset
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  • Control the speed of an ECM motor locally or remotely
  • MODBUS RTU communication with building automation systems
  • Closed-loop control mode will maintain motor speed independent of loading
  • LED display of motor rpm
  • PWM and DC outputs plus GO Signal
763-ECM Fan Control
  • For PSC or shaded pole single phase, single speed motors
  • Optimizes fan speed to improve system performance and save energy
814/816 Head Pressure Control
  • For three phase induction condenser fan motors
  • Optimizes fan speed to improve system performance and save energy
865-3AA PSC Head Pressure Control
  • For PSC or shaded pole motors
  • Low cost manually adjustable proportional speed control
  • Voltage ranges from 120 to 480 Volts, current up to 15 Amps
706 Manual PSC Speed Control
  • For EC Motors
  • Low cost manually adjustable speed control
  • 0-10 VDC output to motor
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  • For EC Motors
  • Low cost manually adjustable speed control
  • PWM output to motor
760-ECM Manual Speed Control
  • For EC Motors with PWM input
  • Allows replacement of discrete speed PSC or EC motors with variable speed EC motors
  • Heating and cooling speeds are adjustable
762-ECM 2 Speed Fan Control
  • For EC Motors with PWM input
  • Allows replacement of discrete speed ECM with variable speed ECM
  • All four speeds are adjustable
764-ECM 4 Speed Fan Control
  • For EC Motors
  • Control input is DC voltage or current
  • PWM output to motor
792-ECM(VmA) Fan Speed Control
  • For PSC and shaded pole motors
  • Control input is DC voltage 2-10V
  • Minimum speed adjustment
  • Continuous flow switch
  • 115/208-230V, 10 amps
880-ECM Head Pressure Controller
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