Hoffman Controls 865D Series User manual

CAUTION
Failure to read and understand the accompanying
instructions and diagrams or failure to complete
the “Checkout Procedure” prior to energizing the
Control may result in permanent damage to the
Control.
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1
865D Series
3 Phase Head Pressure Controllers
General
The 865D Low Ambient Three (3) Phase Head Pressure Control
is designed to modulate three phase condenser fan Motors in air
conditioning and refrigration systems. The control monitors the head
pressure by sensing 1) the sub-cooled liquid line temperature, or 2)
via a 0-10 VDC or 4-20 mA control signal indicating the system's
pressure. The controller varys the air volume through the condenser
thus regulating head pressure for proper heat rejection in low ambient
conditions.
The 865D Series installation instructions are limited to three
phase, direct connected, propeller type, condenser fan motor appli-
cations. These applications require continuously variable speed
High Slip tolerant/Ventilated (HS/V), 850/1150 RPM, direct drive,
vertical shaft designed motors approved by the motor manufacturer
for continuous variable speed operation.
The installation, start-up and servicing of the 865D Control
and the continuously variable speed motor can be hazardous due
to the technical scope and magnitude of the electrical/mechan-
ical components encountered.
A qualified technician with knowledge and experience in
controls and refrigeration will be required. All safety precautions,
instructions, labels, and tags on the items being installed as well as
those of the equipment manufacturer should be observed.
The 865D is offered with a NEMA 3R r a inproof enclosure for
field installation in the weather/ambient.
The 865D Control typically modulates continuously variable
speed HS/V (High Slip/Ventillated) three (3) phase condenser fan
motor(s). Tw o identical condenser motors, of same manufacturer,
type, model, RPM and identical propeller fans, may be controlled
by one 865D Control. In either case, the 8 amp, per phase, rating of
the 865D Control must not be exceeded.
A properly applied 865D Control may be used to extend the
operating range of A/C or refrigeration systems, permitting opera-
tion at lower outdoor ambient temperatures. When more than a
single liquid line sensor requires monitoring, use the HCC 851-
MS series Multiple Sensor Selector.
The 865D Control can also be used as a Manual three (3) phase
Fan Speed Control by using the MIN SPD potentiometer or by a
0-10Vdc or 4-20mA signal
The 865D can either be factory or field calibrated to optimize the
throttling range of the continuously variable speed HS/V motor(s)
for air-cooled condenser applications.
Recalibration of the 865D's factory calibrated settings
can be acomplished in the field when required. If reca-
libration is required, see settings.
The Controller is designed to maintain synchronous (full) speed
for all liquid line temperatures above 80°F. At 80°F liquid tempera-
ture, (60°F ≈ambients) the Controller initiates phase proportioning
by reducing motor speed to approximately 1000 RPM. Speed reduc-
tion continues as liquid temperature decreases down to a minimum
speed which occurs at 50°F (25°F ≈ambient).
Further reduction in liquid line sub-cooling will remove (discon-
nect) the motor from the line and the motor will cycle “Off”. The
motor will restart at 53ºF, 3ºF differential at approximately 100
RPM above where the motor cycled OFF, and modulates back to
the Minimum speed. OFF time will increase as Ambients continue
to fall until liquid line temperature remains below 50ºF. This feature
also allows the 865D to be “Off” at start-up when the ambient and
liquid line are below 50°F. Conversely, the 865D controls the motor
speed functions in reverse as previously described as temperatures
increase.
A 0-–10VDC or 4–-20mA optional signal input is available.
These inputs may be used when pressure transducers or other analog
outputs are preferred.
Below is the general sequence of events required to set up the
865D Control for operation:
The 865D Control is factory calibrated for use with the supplied
liquid line temperature sensor and is set for 50ºF to 80ºF operation
with a minimum speed of 300RPM. These setting can be changed
as required.
A 0-–10VDC or 4–-20mA optional signal input is available.
These inputs may be used when pressure transducers or other analog
outputs are preferred.
A) Use the MODE JP1 jumper to select either Head Pressure
Control operation or Motor Speed control operation.
B) The 865D Control will automatically sense the type of
input signal being used.
Hoffman|Controls
Installation & Operating
Instructions
Controller/Motor Operation
Operational Overview
Applications
Applications Con't

2
C) Use the HIGH SET potentiometer to select the desired
maximum input signal value to operate the motor at maximum
rpm. The HIGH SET potentiometer has three (3) scales associ-
ated with it:
• °F scale (Temperature) - Outside scale
• ma scale - Middle scale
• VDC scale - Inside scale
D) Use the LOW SET potentiometer to select the desired
minimum input signal value to operate the motor at minimum rpm
just before motor cutoff.
•The LOW SET potentiometer has the same three (3)
scales as the HIGH SET potentiometer described above.
Refer to the Modes of Operation section (page 3) for the
MODE jumper, HIGH SET, LOW SET and MIN SPD potenti-
ometers' operating details
Pre-Installation
Before field installation of the 865D, or the HS/V motor, the
installer should carefully evaluate the physical requirements for
installing the new motor and Controller. The check list below will
cover the basic requirements of a field installation.
1. For use with three phase HS/V condenser fan motors capable
of continuously modulating its rpm between minimum and full
speed and vice versa.
2. The control provides 8 amps, per phase, of current and will typi-
cally operate up to a 2 HP motor. However, the current draw of
the motor(s) selected can not exceed 8 running amps of motor
drive capability.
3. The control can monitor one refrigerant circuit with a 10K
liquid line temperature sensor or a 0 - 10 Vdc or a 4 - 20 mA
input signal. The 865D is supplied with one (1) temperature
sensor. When pressure transducers are used the installer must
provide the transducer's power source. Both 0 - 10 Vdc and 4
- 20 mA pressure transducers are market available. Additionally,
the 865D will accept a 0-10Vdc or a 4 - 20 mA manual or BAS
motor speed control signal for non head pressure applications.
4. The control requires an external 24VAC, 1VA power source.
5. Wiring must comply with Local and National Electrical Codes.
6. Refer to 865D Product Data (HCC #172-0270-000) to insure
a complete understanding of the controller's functions before
continuing installation.
The LOW SET point and HIGH SET point adjustments are
critical settings for proper heat rejection in low ambient condi-
tions. The 865D control maintains the pressure differential at the
expansion valve for proper superheat. The LOW SET and HIGH
SET point potentiometers have three scales that provide settings
for temperature (40°-140° F), mA (4 -20) and VDC (0 - 10). Use
the scale that is appropriate for the application. Refer to Figure 2,
"865D Field Wiring Diagram"(on page 5).
Operation with Hysteresis
When the sensed input drops below the selected LOW SET
point, the motor will turn off. When the input rises above the
LOW SET point by the hysteresis value, the motor will turn back
on. The hysteresis value for temperature is 3°F, pressure is 6 PSI
and voltage is 0.8 Vdc.
CAUTION:These various set point adjustments are provided only
to ensure proper ambient control when the system is properly charged
(no vapor in the sight glass), and filters, condenser coil and evaporator
coil are all clean.
When either the LOW SET or HIGH SET potentiometer is
turned, the green SET LED will flash the new set point value. A
sequence of flashes indicates a digit from 1-9. The number zero (0)
is indicated by a longer low-brightness pulse. For example, if the set
point is 105°F, the SET LED will flash once, then pause, then display
a dim glow, then pause, then flash five times. If the input type (Temp,
Vdc or mA) is changed using the MODE jumper, the previously
saved set point values for that particular mode, will be displayed by
the SET LED and used as the current set point values. The SET LED
set point indicator provides the installer with the assurance that the set
points have been entered exactly as desired.
The 865D will automatically detect weather a tempera-
ture, mA or Vdc input is being used and set point scale
ranges for these inputs are as follows:
The temperature LOW SET potentiometer's range is 40 °Fto
80 °F in 1 °F increments.
The temperature HIGH SET potentiometer's range is 60 °Fto
140 °F in 1 °F increments.
The mA LOW SET potentiometer's range is 4 mA to 16 mA
in 1 mA increments.
The mA HIGH SET potentiometer's range is 8 mA to 20 mA
in 1 mA increments.
The Vdc LOW SET potentiometer's range is 0.5 VDC to 8.0
VDC in 0.1 volt increments.
The Vdc HIGH SET potentiometer's range is 6.0 VDC to
10.0 VDC in 0.1 volt increments.
This wide range of adjustment provides head pressure contol for
both typical and unique applications.
The factory setting for the typical temperature sensed applica-
tion with the MODE jumper in the HP position is a LOW SET
point of 50°F and a HIGH SET point of 80°F providing a 30 °F
span (range) for three phase condenser fan motor modulation for
the typical Thermal Expansion Valve (TXV) type systems. In this
example, the condenser fan motor(s) modulates from full speed
which occurs at 80 °F liqiud line (ambients above 60°F) and modu-
lates motor(s) to minimum speed at 50 °F liquid line (ambients
below 30°F).
LOW & HIGH SET Potentiometers
LED Set Point Indicator
Set Point Scale Ranges
Operational Overview Con't

3
The motor(s) cycles "OFF"at liquid line temperatures below 50
°F and cycles back "ON"at 53 °F liquid line temperature providing
3 °F of hysteresis between motor "OFF"and "ON"operation.
A 25 °F span (settings of 75 °F to 100 °F) is recommended for
High Efficiency systems. Settings of 70 °F to 100 °F are recom-
mended for Capillary Tube or Orifice type systems.
The minumim speed "MIN SPD"potentiometer is factory set
at 300RPM for a typical three (3) phase motor minimum speed.
Adjustments to this RPM setting can be made by turn the potenti-
ometer to the desired RPM.
The minimum speed potentiometer can also be used as a Manual
Fan Speed adjustment and will control the speed of the motor from
OFF to FULL speed.
The 865D can is capable of operating in two (2) different modes,
Head Pressure Control mode and Motor Fan Speed Control mode.
When in head pressure mode the 865D accepts one of three
inputs, a 10Ktemperature sensor, a 0-10 VDC or 4-20 mA signal.
When in motor fan speed mode, the 865D accepts a 0-10 Vdc
input or a 4-20 mA input or the MIN SPD pot can be used.
To enter either mode of operation and use one of the accepted
input signals, follow the instructions below;
For Head Pressure Operation Place the JP1 Jumper
in the HP MODEand Connect the Input as Follows:
When using the 10K sensor as the input signal;
•Connect the 10Ksensor wires to terminals S1 and S2.
When using 0 -10 VDC as the input signal;
•DO NOT use the 10Ksensor. Make no connection
between terminals S1 and S2.
• Connect the 0-10Vdc input signal to the GND and
VDC terminals.
When using 4 - 20 mA as the input signal;
•DO NOT use the 10Ksensor. Make no connetion
between terminals S1 and S2.
• Connect the 4-20mA input signal to the GND and mA
terminals.
For Motor Fan Speed Operation Place the JP1
Jumper in the SPD MODEand Connect the
Input as Follows:
When using 0 - 10 VDC as the input signal;
•Connect the 0-10VDC signal to the GND and VDC
terminals.
When using 4 - 20 mA as the input signal;
• Connect the 4-20mA signal to the GND and mA termi-
nals.
When using the MIN SPDpot for speed control;
• Manually adjust the pot from OFF to FULL speed.
Set Point Scale Ranges Con't
The 865D control accepts a single 10Ktemperature sensor input
or a 0-10 Vdc input or a 4 - 20 mA input signal. When additional
temperature sensor input signals are required, the 851-MS Series
Multiple Sensor Selector can be used to monitor between 2 and 10
sensor input signals. The 851-MS Series Sensor Selector passes the
highest monitored sensor temperature to the 865DControl.
The 0 - 10 Vdc and 4 - 20 mA inputs are typically used for either
pressure transducer signals or building automation system signals.
The 865D will automatically detect the type of input signal being
used. If none of the input signals are present, the 865D control
assumes that there are no valid inputs, and will run the motor(s) at
full speed.
These instructions describe field installation procedures for
applications using the special purpose liquid line sensor. The use
of optional input signals is described in the 865D Series Electronic
Head Pressure Product Data.
Controllers must be installed vertically with panel conduit/
wiring openings at the bottom. A 1/2” and 3/4” conduit fitting
opening and a bushing for sensor or input cable is provided.
Howener, conduit connectors are not included. The factory
furnished sensor/hardware kit includes:
One (1) 60” cable assembly and sensor.
One (1) Special sensor installation tape.
Step 1 Disconnect all power, line and control voltages from
equipment.
Step 2 Disconnect control circuit to all compressor relay/
contactors, disabling compressor(s).
Step 3 Install only continuously variable High Slip /
Ventilated direct drive motors capable of continuously
variable speed operation.
Installation Steps
WARNING:
Disconnect power from the unit and electrically
disable the compressor prior to installation to
ensure both are electrically disabled prior to
installation.
IMPORTANT:
Do not install the 865D in an airtight compart-
ment, on a vibrating surface or near/on heat
generating sources.
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Modes of Operation
865D Control Input Signals
MIN SPD Potentiometer

Step 5 Install DVM across T1 and T2, amp meter clamp on
monitor on T1 wire and temperature indicator on liquid
line.
Step 6 Tem porarily remove one of the temperature sensor leads
from S1 or S2. If using a VDC or mA input, remove that
input. With all inputs removed, this will cause the 865D
Control to run the motor(s) at full speed.
Step 7 Phase Sequence Verification
A. Apply line and control voltage to unit(s) observing
voltage and current to motor being controlled.
B. All fan motor(s) should start. Compressor should not
start as a result of previous disabling instructions.
C. If 865D controlled fan motor(s) start, phases are in
sequence. Proceed to Step 8.
D. If motor(s) does not start:
L1, L2, &L3 line voltage input to Controller has
i n correct phase sequencing:
• FAULT LED will be on.
•Remove power.
•Reverse line wires attached to L1 and L2 terminals
on 865D and restore power to unit.
•Motor(s) will start.
• FAULT LED will be off. After 6 second soft start
MTR SPD LED will be full on (not blinking).
Step 8 Condenser Fan Rotation Verification
A. Check condenser for proper airflow (CW or CCW
motor rotation).
B. If motor rotation is correct; proceed to Step 9.
C.I f motor rotation is incorrect, remove power and
reverse wires on 865D terminals T1 and T2.
D.R e -connect control circuit that disabled com-
pressor(s) in Step 2.
E. Restore power to unit. Compressor and condenser
fans will start. Recheck condenser fan(s) for proper
airflow
Step 9 Monitor operation of the 865D and motor(s) at full speed
(850/1150 RPM).
A. Observe the motor's AC voltage and current. Also
monitor liquid line temperature, then verify the MTR
SPD LED is full on.
4
Step 4 Install Line and Low voltage wiring along with Sensor
wiring, as shown in Figure 2, Field Wiring Diagram (on
page 5) and the instructions below.
A. Remove wiring from condenser motor(s) at contactor(s) or
terminal block and reconnect the contactor's wires to the
865D terminals T1, T2, &T3.
B. Field furnish three (3) 90°C wires, of appropriate size for the
application, from condenser fan motor contactor to 865D's
L1, L2 and L3 terminals.
Install the 865D control in ventilated enclosure (indoors) or
NEMA-3R enclosure (outdoors). The control is conformally
coated but must be protected from moisture and condensation.
C. Connect green GND wire on 865D to a reliable ground.
D. Field furnish 24VAC transformer wiring to the 865D's 24V
and COM terminals.
E. Install the supplied 10K Sensor to the top of liquid line where
the line exits the condenser coil as shown below in Figure 1,
Sensor Installation Cross Section Diagram.
F. Use the special tape provided in hardware kit to secure the sensor
to the clean liquid line. Stretch the tape slightly, as you wrap the
tape around the Sensor and liquid line. Use all the tape, lapping
the Sensor. Firm contact is required between the metal tab of the
Sensor and the liquid line. Tie wraps may be used to secure the
sensor to the liquid line, but do not apply too much pressure to
the sensor as breaking its internal components is possible.
Figure 1 - Sensor Installation Cross Section Diagram
G. Route sensor cable from sensor location to 865D Control.
Connect the sensor's wires to the control's S1 & S2 input
terminals. Note: It doesn't matter which sensor wire is
connected to the S1 terminal or the S2 terminal.
•Additional insulation of the taped sensor and adjacent liquid line,
back to condenser header, is typically required in cold ambients
(+20°F).
• Refrigeration applications or extremely low ambient environ-
ments may require additional consideration. See Engineering
Bulletin (HCC #81XEB02REVA) for “Low Ambient
Considerations”.
•When monitoring two to ten refrigerant circuits, install the
Hoffman Controls 851-MS Series Multiple Sensor Selector.
H. Verify unit manufacturer has provided fuse or circuit breaker
protection for motors being controlled and field wiring did not
remove or bypass motor protection.
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Installation Steps Con't
NOTE:
The following evaluation in Step 9 will validate the
performance of the 865D Control and HS/V motor.
NOTE:
The completion of Steps 1 through 8 verifies the integrity
of the electrical installation.
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5
Figure 2 - Field Wiring Diagram
B. When above measurements are correct, reconnect the
input signal.
C. Depending upon the observed liquid line tempera-
ture, the following performance values should be
observed.
1) As liquid line temperatures decrease from selected
HIGH SET temperature to selected LOW SET
temperature:
• Motor speed (RPM) decreases.
• Voltage to motor decreases (when viewed on
RMS meter).
• Current (amps) increases, peaks, then
decreases, due to PSC motor's design.
2) As liquid line temperatures increase from selected
LOW SET temperature to selected HIGH SET
temperature:
• Motor speed (RPM) increases.
• Voltage to motor increases (when viewed on
RMS meter).
• Current (amps) increases, peaks, then
decreases, due to PSC motor's design
Liquid Motor Speed MTR SPD
Te m perature (RPM) LED status
Above HIGH SET point 1150 Full
Between HIGH &
LOW SET points <1150 to 300 Modulate
Below LOW SET point Zero Off
Installation Instructions Con't
The 865D can be used as a
Head Pressure Control with
a Temperature Sensor input
or a Vdc or mA Pressure
Tr a nsducer input. The
865D can also be used as a
Manual Fan Speed Control
by using the MIN SPD pot
or a 0-10Vdc input signal
or a 4-20mA input signal.
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6
1. Verify line voltage is correctly applied to the motor(s) termi-
nals.
2. Verify motor(s) has been programmed for correct rotation
(CW/CCW) and is selected for the reccommended propeller
Prepare for Operation
1. Itis recommended that the compressor be disabled prior to
control and condenser fan motor(s) operational checkout.
1. Apply power to both the 865D and condenser fan motor(s).
Verify the FAULT LED is off.
2.Once the control and motor(s) wiring has been verified, restore
the compressor's power.
3.
Set thermostat for cooling demand and apply voltage to
the unit. Condenser fan(s) will start if the liquid line is 3
°F
above the LOW SET point temperature value and modu-
late over the span of the range selected
.
4. Verify that the motor is operating properly for liquid line
temperatures sensed. Depending on the LOW &HIGH set
points, when the sensor's temperature at start up is:
a. Below Selected Range,the motor(s) will not start.
b. Within Selected Range, the motor(s) will start and the
865D will modulate the motor's rpm proportionally to
the temperature sensed.
c. Above Selected Range, the motor(s) will soft start and
then remain at full speed.
5. Verify operation as described above by monitoring liquid line
temperature and observing motor speed.
6. When using pressure transducers (Vdc or mA) or BAS inputs,
monitor the control signal verses motor rpm for proper opera-
tion.
New Motor Installation Checklist
1. Verify the existing motor’s bracket/support accepts
the NEW HS/V continuously variable, 56 frame (6 1/2”)
d i ameter motor.
2. Verify the existing fan blade accepts the NEW HS/V motor's
5/8” diameter shaft.
Controller Installation Check List
Where will the 865D be located:
1. Inside a ventilated control panel?
2. Mounted externally in ambient (exposed to the weather) on
the unit adjacent to the existing motor/control panel?
3. To allow access to wiring connections and calibration adjust-
ments?
Checkout Procedure
CAUTION
Verify all three phase motor connections & 865D
connections are correct before applying power.

CAUTION
865D Series Head Pressure Controllers are not
suitable for mounting inside a totally enclosed
or non ventilated control panel that exceeds
160°F (70°C).
NOTE:
Removing the sensor input signal or the Vdc/mA
input signal will allow the motor(s) to start and
operate at full speed without concern for sensor
temperature and will verify the control and
motor(s) are operating correctly.
NOTE:
The 865D Control is factory calibrated for use with
the supplied liquid line temperature sensor and is
set for 50ºF to 80ºF operation with a minimum
speed of 300RPM. These setting can be changed as
required.


7
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
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Typical Fan Operation with Ambient, Condensing, and Liquid Line Temperatures

8
Temperature to Resistance Table - Key Point Values
Tab le 1
Temp
ºF
Sensor
(Ohms)
Temp
ºF
Sensor
(Ohms)
Temp
ºF
Sensor
(Ohms)
40.0 26,109 64.0 13,823 88.0 7,685
42.0 24,712 66.0 13,139 90.0 7,332
44.0 23,398 68.0 12,492 92.0 6,997
46.0 22,160 70.0 11,881 94.0 6,679
48.0 20,996 72.0 11,3033 96.0 6,378
50.0 19,899 74.0 10,8509 98.0 6,092
52.0 18,872 76.0 10,2095 100.0 5,820
54.0 17,903 78.0 9,750 102.0 5,561
56.0 16,990 80.0 9,287 104.0 5,316
58.0 16,128 82.0 8,848 106.0 5,094
60.0 15,315 84.0 8,433 108.0 4,873
62.0 14,547 86.0 8,056 110.0 4,662
Troubleshooting Guide
Motor Will Not
Run
Motor Runs
at Full Speed
Only
Motor
Overheats
1. Improper installation, Motor not wired correctly.
2. Sensor temp below LOW SET point value.
3. Motor “OFF” on internal overload.
1. Motor not wired correctly.
2. Motor not wired correctly. Control damaged.
3. Low refrigerant. (Hot gas in liquid line.)
4. Sensor opened. (Verify Ohms vs. Temp.)
5. Sensor temp above HIGH SET point value.
1. Minimum speed set too low.
2. Motor design not applicable for continuously variable speed
o p eration.
1. Sensor not properly located or attached to liquid line.
2. Fan blade does not load motor at full RPM (speed).
3. Sensor resistance (in ohms) vs. temperature (in °F) not in
c o mpliance with values in Ta b le 1.
4. Motor design not applicable for continuously variable speed opera-
tion.
5. System not properly charged.
6. Expansion valve is not properly metering refrigerant; cap tube or
orifice not properly sized for low ambient operation.
7. Low evaporation and head pressure.
Motor Will
Not Modulate
Properly
Condition Cause Solution
1. Check wiring, review instructions.
2. Normal operation.
3. Motor protected.
1. Check wiring, review instructions.
2. Replace control.
3. Charge system.
4. Replace Sensor.
5. Normal operation.
1. Raise MIN SPD RPM.
2. Replace motor.
1. Relocate per instructions.
2. Compare FLA rating to measured FLA.
3. Replace Sensor.
4. Replace Motor.
5. Recharge system. Add or remove refrig-
erant. (Liquid line must not indicate
vapor/gas.)
6. Adjust or replace expansion valve, cap
tube or orifice to provide proper control
of lowside.
7. Reset LOW &HIGH pots CW to pro-
vide evaporator temperature above 32°F.