709D-VmA and 709E-VmA Series
Electronic Fan Speed Controllers
Hoffman
|
Controls
Installation & Operating
Instructions
1
Introduction
The 709 Series of Electronic Fan Speed Controllers consists of two
models. These 2 models allow for the option of deriving power
for the control via an external 24 VAC transformer (provided
by customer), or directly from line and phase of the “onboard”
PCB mounted transformer. The 709D does not include the 24
VAC transformer. The 709E includes the transformer internally
connected to the line voltage.
Each of these models have the option of using a Hoffman Controls
Proportional Integration (PI) Interface plug-in PCB assembly.
This document contains instructions for establishing the electrical
connections for each of the 709 Series controllers’ four configura-
tions.
The 709E controller has sufficient VA (power) to drive the
optional Proportional Integration (PI) Interface plug in card and
one of the the following signal sources; a Hoffman Controls 203-
5(24)V Flow Transducer, a 203-6(24)P Pressure Transducer, or a
906VmA Thermostat. IMPORTANT: When using 709D series
controllers, select a transformer to meet the requirements of all the
components being used.
Initial Controller Installation
Motor Line Voltage Wiring (Figures 1 & 2)
Connect one side of the motor to the "LOAD" terminal on the
709D PCB. Connect the other side of the motor to L1.
Connect L2 or Neutral to the "LINE" terminal on the 709D PCB
assembly.
24 Volt Wiring (Figures 1&2)
Connect the primary side of the 24 VAC transformer to the same
L1 & L2 or Neutral as the motor.
The primary of this external 24 VAC transformer MUST BE THE
SAME PHASE that is supplying power to the motor.
Connect the leads of the 24 VAC transformer secondary to the
"24V IN" & adjacent "GND" terminals of the 709 PCB assembly.
The GND terminal allows for a grounded secondary of the 24 volt
transformer if required.
Do not share this AC GND with DC signal
sources, use a separate wire connection for dc signal ground.
Control Signals (Figure 1)
The 709D accepts industry standard 2-10 VDC or 4-20 ma input
signals. Connect the 2-10 VDC or 4-20 mA control signal and
it's GND reference to their respective terminal block locations.
There is a common signal GND shared by both VDC and mA.
PI Interface Option (Figure 2)
IMPORTANT: The PI Interface Option will replace the standard
2-10 VDC and 4-20 mA inputs on the 709D control. When using
this option the control signals are connected to their respective
terminals on the PI Interface PCB, not the 709 PCB terminals.
Insure that all power sources have been disconnected.
Remove longer top cover of 709D or E (with B or C suffix) model
controller by removing (4) self-tapping screws.
Secure the controller via the heat sink mounting tabs.
Connect the green wire to earth ground.
709D Wiring
Transformer Phasing
The model 709D Series Electronic Fan Speed Control requires an
external 24 VAC source.
This 24 VAC SOURCE MUST BE IN
PHASE with the line voltage being supplied to the motor
. Motor
line voltage and transformer primary MUST be on the same
phase/lines.
709E Wiring
Transformer Phasing
The model 709E Electronic Fan Speed Control contains an inter-
nal transformer to provide the required 24 VAC that is "in phase"
when the speed control is required to function.
Motor Wiring (Figures 3 & 4)
Connect one side of the motor to the "LOAD" terminal on the
709E PCB. Connect the other side of the motor to L1.
Power Supply (Figures 3 & 4)
Connect L2 or Neutral to the "LINE" terminal on the 709E
PCB. Connect L1 to the 120 VAC or 208-240 VAC terminal as is
appropriate for the voltage required.
Control Signals (Figure 3
)
The 709E accepts industry standard 2-10 VDC or 4-20 mA input
signals. Connect the 2-10 VDC or 4-20 mA control signal to
their respective terminal block.
There is a common signal GND shared by both VDC and mA.
PI Interface Option (Figure 4
)
IMPORTANT: The PI Interface Option will replace the standard
2-10 VDC and 4-20 mA inputs on the 709E control. When using
this option the control signals are connected to their respective
terminals on the PI interface PCB, not the 709 PCB terminals.
PI Interface Options
The 709 series of controllers have an available PI Interface option.
The PI Interface will allow for two modes of fan speed control in
relation to a setpoint.
In the Direct Acting or "DA" mode, the PI Interface does not
provide an input to the 709 series control until a control signal has
exceeded the setpoint level.
In the Reverse Acting or "RA" mode, The PI interface will contin-
uously provide an input to the 709 series control in an attempt to
maintain a control signal at the setpoint level.
Refer to the Hoffman Controls PI Interface Product Data Sheets,
PI Interface Installation & Operation Instructions, or Application
Notes literature for complete details on the operation of the
optional PI Interface board.
