Hoffman|Controls
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865-3AA Series
Recalibration Instructions
General
The 865-3AA Series Three Phase Condenser Motor Speed
Controller is factory calibrated and should not require
recalibration. Recalibration is not recommended until the
Controller is installed and the factory calibration perfor
mance is observed to be unacceptable.
The Controller is designed to allow full speed for all
ambient temperatures until a liquid line temperature of 80°F
is obtained (
line temperature, the Controller will modulate the condenser
fan motor(s) speed until the ambient temperature results in
a liquid line temperature of 50°F (
the Controller will be operating at the preset minimum RPM.
Liquid line temperatures below 50°F will disconnect the
condenser fan motor from the line. Condensor motor will
cycle OFF and ON, over time, from 50ºF to 53ºF at Minimum
Speed until ambient precludes liquid line Temperatures
above 50ºF to occur.
Controllers should not be re-calibrated to condensing
pressure. The condensing pressure, once minimum speed is
reached at 50°F-liquid line (
100-psi (R22 for TX valve) plus the specific evaporator pres
sure for the application/refrigerant. When the Controller is
unable to provide this minimum pressure limit, recalibration
may be required.
Proper operating performance can only be obtained with a
saturated, sub-cooled liquid at the Sensor at all times.
Verification of proper super heat control at TX valve
is important (6–10ºF
control may cause or allow excessive liquid flooding or
abnormally low evaporator pressure. Either could adversely
effect head pressure control performance.
The following instructions are provided for liquid line
sensing (preferred method), mA/volts DC inputs, or manual
speed control.
≈ 60°F ambient). Between 80°F and 50°F liquid
≈ 25°F ambient). At 50°F,
≈ 25°F ambient), should provide
≈ super heat). Improper super heat
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Three Phase Head Pressure Controller
5. Adjust the CALIBRATE pot clockwise (CW) until the
FULL L.E.D. light comes ON. Backoff the CALIBRATE pot
until the FULL L.E.D. light just goes OFF. This places the
calibration point at the top end of the modulation range.
6. Adjust the MAX. ADJ. pot to achieve the desired max
speed for the top end of the modulating range.
7. Adjust the CALIBRATE pot counter-clockwise (CCW)
until the OFF L.E.D. light comes ON (this will shut
the motor OFF). Now, slowly adjust the CALIBRATE
pot clockwise (CW) until the OFF light goes OFF (the
modulate L.E.D. will come ON at this same time).
CAUTION
Allow the soft-start time to expire
(10 seconds).
8. Adjust the MIN. ADJ. pot to achieve the desired min
speed at the bottom end of the modulating range. Do
not adjust below 200 RPM minimum.
9. The Minimum Adjustment pot interacts with the
Maximum Adjustment pot; therefore repeat steps 5
through 8 one time.
10 Remove the jumper tab J1 from the CAL/MAN SPEED
position and return it to its OPERATE/STORE position.
11. Adjust the CALIBRATE pot fully counter-clockwise (CCW).
12. Reconnect the Thermistor Sensor.
NOTE
This recalibration procedure allows adjustment of the
min/max fan speeds within the modulation range,
but will not change the span or fan cutoff threshold
(temperature) of the Controller.
Field Calibration for
Thermistor Sensor
1. Disconnect Thermistor Sensor.
2. Adjust the CALIBRATE pot fully counter-clockwise (CCW).
3. Place the calibration jumper (J1) tab to the CAL/MAN
SPD position to enable the on-board sensor simulator.
4. Set both the MAX. and MIN. adjustment pots to mid
range.
Field Calibration for Volt/mA
Auxiliary Inputs
1. CAL/MAN SPEED (J1) jumper is not used, leave in the
OPERATE/STORE position.
2. When VDC or mA are required, remove the liquid
line Sensor.
3. Set the MAX. and MIN. adjust pots to their mid-range
positions; attach appropriate VDC or mA input.
4. Apply an increasing DC or mA level to the Volts/mA
INPUT until the FULL L.E.D. light comes ON. This
should occur at approximately 4.875 volts, 9.75 volts or
19 mA. Lower the input level to a point where the FULL
L.E.D. light just goes OFF. This sets the input signal at
the top of the modulating range.
5. Adjust the MAX. ADJ. pot to achieve the desired
maximum speed for the top of the modulating range.
6. Lower the input level (volts or mA) until the OFF L.E.D.
light comes ON. This should occur at approximately
0.8-volts, 1.6 volts or 2 mA. Raise the input level to a
point where the OFF L.E.D. light just goes OFF and the
MODULATE L.E.D. just comes ON.
7. Adjust the MIN. ADJ. pot to achieve the desired min.
speed at the bottom of the modulating range.
8. The Minimum Adjustment pot interacts with the
Maximum Adjustment pot; therefore repeat steps 4
through 7 one time.
The Controller should now modulate from full OFF
through the modulation range to full ON producing the
desired speed (RPM) over the 0–5V DC, 1–10V DC or
2–20mA range.
6. The Controller will now maintain the manually set
motor speed whenever energized.
Liquid Line Temperature
Sensing
Liquid Line Temperature Sensing is directly proportional to Saturated Condensing temperature (Condensing
Pressure). When ambient, air flow Temperatures of 60ºF
are encountered, liquid line temperature values are 80ºF.
At this liquid condensing Temperature, a 105ºF saturated
liquid line condensing liquid temperature will occur. The
condensor is modulated from 80ºF to 50ºF± temperature.
Once 50ºF is reached the condensor air flow has reached
Minimum Flow as determined by the Minimum Speed setting, and 100ºF± saturated condensing liquid temperature
will occur.
For all liquid Temperatures between 50ºF and 53ºF, the
fan will cycle OFF and ON at Minimum Speed to maintain
a 3ºF differential of liquid line temperatures, as ambients
continue to fall the fan will remain OFF longer until ambi
ents preclude any fan ON function. Once fans remain OFF,
all low ambient control will cease to function.
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Field Calibration for Manual
Speed Control (No Inputs)
The 865-3AA Controller may be used as a manually set
three phase motor speed control. To adjust:
1. No signal inputs are required in this application.
2. Adjust the CALIBRATE pot fully counter-clockwise (CCW).
3. Place CAL (J1) jumper in the CAL/MAN SPEED position
as illustrated.
4 Adjust the CALIBRATE pot clockwise (CW) until the FULL
L.E.D. indicator comes ON. Back off the CALIBRATE pot
until the desired motor speed is attained.
5. Ensure motor speed is 200 RPM or greater.
Hoffman|Controls
2463 Merrell Road, Dallas, Texas 75229 • Phone: (972) 243-7425 • Fax: (972) 247-8674 • Toll Free: 1-888-HCC-1190
www.hoffmancontrols.com Form: 176-0183-000 Rev.A
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