Honeywell T775A2009, T775B2032, T775B2016, T775B2024, T775B2040 Application Manual
...
T775 Series 2000 Electronic
Stand-Alone Controllers
APPLICATION GUIDE AND CROSS REFERENCE
63-7147-05
T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
IMPORTANT
The T775R is an operating control, not a limit or safety control. If used in applications requiring safety or limit controls, a
separate safety or limit control device is required.
TABLE OF CONTENTS
T775 Application Tips .............................................. 3
Compatible Components......................................... 3
Temperature Sensors................................................. 3
Humidity Sensors (T775U only) ................................. 3
Low Differential Pressure Sensors (T775U only) ....... 3
Universal Sensors (T775U only) ................................ 3
Accessories................................................................ 4
Features .................................................................... 4
T775 Operations....................................................... 6
Integral Action ............................................................ 6
Derivative Action ........................................................ 6
Differential vs. Throttling Range................................. 6
Setpoint High Limit..................................................... 6
Reset Programming
(T775L, T775P, T775R, and T775U models only)...... 7
T775 Applications .................................................... 8
Water Source Heat Pump Loop
Water Controller – T775B ......................................... 8
Chiller – T775B .......................................................... 9
Chiller, Rotary Compressor – T775B ....................... 10
Cooling Tower Control – T775B2040 ........................11
Time-based Control of Fan,
Pump, etc. — T775 (all models) .............................. 12
Damper or Valve Modulation – T775M or T775R..... 13
Hot Water Reset – T775R........................................ 14
Chilled Water Reset – T775R .................................. 16
Multi-Stage Boiler Control (No Reset) – T775P ....... 17
Multi-Stage Boiler Control (Reset) – T775P .............18
Multi-Stage Chiller Control (No Reset) – T775P....... 20
4 Stage with Pump Output and Reset –
T775P using a T775S Expansion Module ................21
4 Stage with Pump Output and Reset (continued) ... 22
3 Stage Reciprocating Chiller – T775L ..................... 23
4 Stage Heat and 6 Stage Cool – T775L ..................24
4 Stage Heat and 6 Stage Cool (continued) .............25
Pressure with a Variable
Frequency Drive (VFD) – T775U..............................26
Carbon Dioxide (CO2) Sensing – T775U ................. 27
Resetting Zone Air Temp Based on
Outside Air Temp (2 stage cooling) .......................... 28
Resetting Discharge Air Temp Based
on Return Air Temp (Modulating cooling valve) ........ 29
Using the T775R as a Differential
Temperature Controller for Solar Water Heating ...... 30
Maintaining Differential Temperature
for both Heating and Cooling....................................32
T775 Application Replacement Examples 33
T775M2030 Replacement for W973A Logic Panel ..33
T775R Replacement for W964F Aquatrol
Panel with Floating Actuator.....................................35
T775L Replacement for S984 Step Controller.......... 38
T775L Replacement for W7100C
Discharge Air Controller ........................................... 41
T775 Cross Reference............................................44
Notes........................................................................55
63-7147—05 2
T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
T775 APPLICATION TIPS
Q Does the T775 save programmed values if the power is
lost?
A Yes. The T775 has an EEPROM that saves all values
entered and restores them once power is reapplied. The
date and time settings are retained for 24 hours after a
power outage. After a power loss of more than 24 hours,
the date and time settings may need to be reentered. All
other settings are stored permanently.
Q What is the time constant for the T775?
A The T775 standard sensor (50021579-001) has a time con-
stant of approximately 8 seconds. The T775 samples sensor input every 100 milliseconds and updates the control
and display every 1 second.
Q Can sensors be shared by several T775s to simplify instal-
lation or provide more stages?
A Each T775 must be wired to its own sensor(s), However, a
benefit of the T775 controller's high accuracy is that there
is no more than a 2° differential between any two T775
controllers.
COMPATIBLE COMPONENTS
Temperature Sensors
The controller accepts 1,097 Ohms PTC at 77° F (25° C):
• 50021579-001 – Standard sensor (included with all models
except T775U2006 and NEMA 4X models)
• T775-SENS-STRAP – Strap on sensor with wiring box
• T775-SENS-WR – Water resistant with 5 foot leads
(included with NEMA 4X models)
• T775-SENS-WT – Watertight with 6 foot lead
• T775-SENS-OAT – Outdoor air temperature sensor
• C7031B2005 – 6 inch duct mount with wiring box.
• C7031D2003 – 5 inch immersion sensor with wiring box
(use immersion well; P/N 50001774-001)
• C7031J2009 – 12 foot duct averaging sensor with wiring
box
• C7046D1008 – 8 inch duct probe with mounting flange
• C7100D1001 – 12 inch fast response, duct averaging
sensor with flange
• C7130B1009 – Room mount sensor
Humidity Sensors (T775U only)
The controller accepts 0-10 Vdc or 4-20 mA input with a range
of 0-100%
H7625, H7635, and H7655 models (available in 2, 3, and 5%
RH accuracy) can be used.
1
Q Can a T775 be powered with dc voltage?
A No. The T775 controllers may be powered with 24 Vac,
120 Vac, or 240 Vac only, and a separate earth ground is
required.
Q Is a separate earth ground required?
A Yes. Each T775 controller must have its own earth ground,
regardless of the power source (24, 120, or 240 Vac). The
earth ground must be connected to the earth ground terminal on the 24 Vac terminal block.
Q Can sensors be series-parallel wired to the T775 to provide
an average temperature?
A Yes. Sensors can be series-parallel wired to the T775. In
order to maintain control accuracy, the number of sensors
wired must be of the n
Q How do I know that my selection or value has been
entered?
A Once you have selected an item from a list or entered a
value using the and buttons, pressing the or or
HOME button accepts your selection or value and stores it
in the controller’s memory.
Q What are the T775 Series 2000 Controller specifications?
A Refer to the T775 Series 2000 Electronic Stand-Alone
Controllers - Specification Data (form 63-1318).
2
power (i.e. 4, 9, 16, etc.).
Low Differential Pressure Sensors (T775U only)
P7640A pressure transducer models with selectable pressure
ranges can be used.
The controller accepts pressure sensors with a signal output
of 0-10 Vdc or 4-20 mA for any output range within the
following ranges (the minimum and maximum for the sensor
output range can be adjusted within the following limits):
-500 to 500 PSI
-30.0 to 30.0 inches w.c.
-3,000 to 3,000 Pa
-3,000 to 3,000 kPa
Universal Sensors (T775U only)
The controller accepts 0-10 Vdc or 4-20 mA input for
temperature, pressure, humidity, etc. C7232 and C7632 CO
sensors are also compatible but output is displayed in %
instead of ppm. (Refer to Table 2 on page 35 and the T775U
installation Instructions, form 62-0255-01.)
Actuators
For more information on compatible actuators or other
Honeywell products, such as dampers and valves, go to
www.customer.honeywell.com. From the home page select
Product Selection Tool under Products.
• Spring return models: ML6425, ML7425, MS4105,
MS4110, MS4120, MS7505, MS7510, MS7520, MS8105,
MS8110, MS8120
• Non-spring return models: ML4161, ML6174, ML7161,
ML7164, MN1010, MN6105, MN7505, MN8810
1
See form 62-0265 - Temperature Sensor for the T775 Series
2000 Stand-alone Controller
2
3 63-7147—05
T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
Accessories
• 107324A – Bulb Holder, duct insertion
• 107408 – Heat Conductive Compound, 4 ounce
• 50001774-001 – Immersion Well, stainless steel 304,
1/2 in. threading
Table 1. T775 controller features by model number.
Feature
User Interface
2x4 inch LCD display with English language display n/a
Keypad lockout n/a
Applications
Standard heating/cooling
Modulating
Boiler/Chiller
Reset
Stage (Loop) control of up to 12 relays
Temperature, humidity, pressure, or other
application requiring 0-10 Vdc or 4-20 mA input
Expansion module (4-relays per module; 2 modules
max.)
Power
24 or 120/240 Vac with separate earth ground
Relay Outputs
SPDT
Number of standard 124244042424442202 4
Number of floating
(each floating output eliminates 2 relays)
Runtime displayed on relays 1-4 (optional) n/a
Configurable minimum off time
Expandable to 12 relays using T775S expansion
modules (4 relays per expansion module)
Warm weather shutdown n/a
Modulating Outputs
Number of outputs 000000222220022022 0
Independently selectable for 0-10 Vdc, 2-10 Vdc,
4-20 mA, or Series 90
Modulating high/low limit control n/a
Digital Output
Number of outputs 000000000001000000 0
High, low, and differential alarm
Pump Output (configurable for last relay)
Number of outputs 000000000001000000 1
Prepurge/Postpurge
Pump Exercise
T775A2009
T775B2016
T775B2024
012120000000200100 0
FEATURES
In Table 1 a check mark () indicates that the controller model
has this feature. A number indicates the quantity (e.g., the
T775M2030 has 4 standard SPDT relay outputs), and
“n/a” indicates the feature is not applicable to that controller
model.
T775M2006
T775M2014
T775M2022
T775M2030
T775B2032
T775B2040
T775L2007
T775M2048
T775P2003
T775R2001
T775R2019
T775R2027
T775R2035
T775R2043
T775U2006
T775S2008
63-7147—05 4
T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
Table 1. T775 controller features by model number. (Continued)
T775M2006
T775M2014
T775M2022
T775M2030
T775A2009
T775B2016
T775B2024
T775B2032
T775B2040
T775L2007
T775M2048
T775R2001
T775R2019
T775R2027
T775R2035
T775R2043
T775P2003
T775U2006
T775S2008
Feature
Sensor Inputs
Number of sensor inputs 122222222223222222 0
Number of sensors included 111111111113222220n/a
1097 Ohms PTC at 77° F (25° C) n/a
0-10 Vdc or 4-20 mA input for temperature, humidity,
n/a
pressure, etc.
Calibration capability ±10° F (±6° C) or
n/a
for T775U, ±10% of sensor range
1° sensed temperature accuracy n/a
Sensed temperature range from -60° to 270° F
n/a
(-51° to 132° C)
Digital Input
Number of inputs 111111111111111111 1
Setpoints
Maximum number of setpoints 124244264641464224n/a
Range -40° to 248° F (-40° to 120° C)
Maximum high setpoint option (irreversible) n/a
Integral and Derivative Options
Integral time selectable from 0 to 3,600 seconds n/a
Derivative time selectable from 0 to 3,600 seconds n/a
Staging
Standard staging
First on, first off
Equalized runtime
On delay and Off delay between stages
Time Clock Scheduler
DST option n/a
2 events per day n/a
Selectable for setback, disable, or ignore to control
n/a
all outputs
Enclosures
NEMA 1
NEMA 4X
5 63-7147—05
T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
T775 OPERATIONS
Integral Action
“Droop” and equipment hunting can be minimized by
summing (integrating) the offset errors over time and adding
this correction to the output voltage.
A non-zero value for the integral time will allow the controlled
temperature to try and reach the setpoint value.
The integral time is factory set for 400 seconds and is similar
to the response time of the T775 Series 1000 models. This is
a good middle range and should satisfy many applications.
The integral time can be increased for applications where
sensed response is slow, and can be decreased for
applications where sensed response is fast (e.g. discharge air
control).
As a starting point, an optimal integral time for discharge air
typically ranges from 12 to 200 seconds. An optimal integral
time for room control typically ranges from 60 to 2,500
seconds. The purpose of integral action is to reduce or
eliminate the offset from setpoint during steady state control
that is often seen in proportional-only control.
Keep in mind that the controller is most sensitive to throttling
range. Adjust the throttling range first before making any
adjustment to integral time. Adjust throttling range to be as
wide as possible to start, because this will provide the most
stable control. Remember that the integral will eliminate the
steady state error so you do not need to have a small throttling
range to have accurate control. (Integral action allows for
controlling to setpoint even with a wide throttling range.)
Derivative Action
Proportional-integral-derivative (PID) control adds the
derivative function to PI control. The derivative function
opposes any change and is proportional to the rate of change.
The more quickly the control point (actual sensed
temperature) changes, the more corrective action the PID
system provides.
If the control point moves away from the setpoint, the
derivative function outputs a corrective action to bring the
control point back more quickly than through integral action
alone. If the control point moves toward the setpoint, the
derivative function reduces the corrective action to slow down
the approach to the setpoint, which reduces the possibility of
overshoot. The rate time setting determines the effect of the
derivative action. The rate time is the time interval by which
the derivative function advances the effect of the proportional
action. In T775 controllers, the derivative rate time can range
from 0 to 3,600 seconds. The higher the derivative setting, the
greater the effect.
For all T775 Series 2000 controllers, the derivative default
value is factory set to zero (no derivative control). It is strongly
recommended that the derivative remain at zero (0) unless
you have a very good reason to adjust it. Derivative control is
not needed in the vast majority of HVAC applications.
Setpoint and Differential
The following describes the relationship between setpoint and
differential for heating and cooling. These settings are
programmed for each output relay.
HEATING MODE SETPOINT AND DIFFERENTIAL
In heating mode, the differential is below the setpoint. The
relay de-energizes when the temperature rises to the setpoint.
As the temperature drops to the setpoint minus the
differential, the relay energizes.
COOLING MODE SETPOINT AND DIFFERENTIAL
In cooling mode, the differential is above the setpoint. The
relay de-energizes when the temperature falls to the setpoint.
As the temperature rises to the setpoint plus the differential,
the relay energizes.
Throttling Range
The throttling range brackets the setpoint setting, e.g., if the
setpoint is 72° F (22° C) and the throttling range is 10° F
(-12° C), then the effective throttling temperature range is
67° to 77° F (19° to 25° C) . This applies to both modulating
outputs and floating outputs.
Throttling Range for Modulating High or
Low Limit
On models that support this feature, the throttling range for
the modulating high or low limit positions the setpoint at the
end of the throttling range. For example, with a high (Heat)
limit at Sensor B of 200° F (93° C) and a throttling range of
10° F (-12° C), the modulating output controlling Sensor A
begins to throttle back at 190° F (88° C), and fully closes at
200° F (93° C). Conversely, the throttling range for the low
limit begins above the Cooling setpoint in the same manner.
Setpoint High Limit
You can set an irreversible setpoint high limit maximum value
for any single setpoint temperature value. This prevents the
user from setting any setpoint above the chosen high setpoint
limit, which is useful for meeting some local codes.
Adjust the setpoint (at any output) to the desired maximum
setpoint. Then, simultaneously press the HOME, , and
buttons, and continue to press all three buttons for five
seconds to set the setpoint high limit maximum to this value.
NOTE: You must press all three buttons at exactly the same
time for this action to occur.
IMPORTANT
1. This action sets the maximum setpoint value of all
outputs to the setpoint high limit maximum.
2. Setting the high limit setpoint maximum is
irreversible. If you perform the action inadvertently
and this setpoint adversely affects the control of your
system, you must replace the controller.
Differential vs. Throttling Range
Differential is used for relay outputs, and throttling range is
used for modulating outputs.
63-7147—05 6
T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
SENSOR B
SP MAX A1
(BOILER MAX)
SP MIN A2
(BOILER MIN)
200
140
10
SETBACK
OFFSET
-10°F
190
20
30 40 50 60
70
°F80
150
160
170
210
220
180
°F
RESET B1
(OUTSD MIN)
RESET B2
(OUTSD MAX)
S
E
N
S
O
R
A
M24861
Reset Programming (T775L, T775P, T775R, and T775U models only)
To program an output for reset, refer to the values as shown in
the example below and in Fig. 1. Choose your own
appropriate values for Sensor A maximum and minimum and
Sensor B maximum and minimum.
Reset Example:
• Sensor A is the boiler sensor and Sensor B is the
outdoor sensor.
• Maximum boiler temperature desired is 210° F (99° C)
when the outdoor temperature is 20° F (-7° C).
• Minimum boiler temperature desired is 160° F (71° C)
when the outdoor temperature is 70° F (21° C).
With the above settings example, when the outdoor
temperature is 50° F (10° C), the effective setpoint is 180° F
(82° C).
Setpoint Offset
NOTE: The Setpoint Offset is used for subsequent
This value is the number of degrees plus (+) or minus (-) that
you want the temperature to be offset from the first output’s
setpoint. See Fig. 1. For example, If you want the second
output setpoint to be 10° F (-12° C) less than the first output
setpoint, enter -10° F (-23° C).
.
outputs only.
SP MAX A1
(BOILER MAX)
S
E
N
S
O
R
A
SP MIN A2
(BOILER MIN)
220
210
200
190
180
170
160
150
140
°F
RELAY 2
SETPOINT
OFFSET
-10°F
10
20
RESET B1
(OUTSD MIN)
RELAY 1
SETPOINT
30 40 50 60
(OUTSD MAX)
SENSOR B
70
RESET B2
°F80
M24862
Choose Reset = NO for any outputs you do not wish to reset,
then press the HOME button to record your selection.
NOTES:
1. A single reset curve is programmed for the first
output and is used by all outputs setup for Reset.
2. For subsequent outputs, a setpoint offset is used
if that output is also being Reset.
When Reset is programmed, the home screen conveniently
displays the calculated Heat/Cool setpoint(s) for the outputs
based on the reset curve.
Setback (Optional) Description
The Setback temperature option is available only if scheduling
is enabled or the Digital Input Option is set to Setback.
This value is the number of degrees plus (+) or minus (-) that
you want the temperature to be setback (offset) from the
setpoint at a predetermined time.
For example, if you want the temperature to be 10° F (-12° C)
less than the setpoint during setback mode, enter -10° F
(-23° C). See Fig. 2.
In normal operations for heating, the offset will be a negative
value; for cooling, the offset will be a positive value.
Setback (optional) Example:
Setback of -10° F (-23° C) is used to drop the temperature at
night by 10° F (-12° C).
With the above settings example, when the outdoor
temperature is 50° F (10° C), the effective setback setpoint is
170° F (77° C) 180° F (82° C) setpoint minus the 10° F
(-12° C) setback).
Fig. 1. Reset curve with offset for subsequent outputs.
The reset curve established when programming the first
output (Fig. 1) is then used for all subsequent outputs that are
configured for Reset = YES, and each of those outputs will be
offset from this curve.
Fig. 2. Reset curve for first output with setback offset.
7 63-7147—05
T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
L1
L2
SENSOR A
(LOOP WATER)
C
NO
NC
C
NO
NC
C
NC
NO
C
NC
NO
T
T
HI TEMP
ALARM
RELAY
1
SUBTRACT
HEAT
LO TEMP
ALARM
C
+
ADD
HEAT
RELAY
4
RELAY
3
RELAY
2
T775B
120
COM
240
1
2
120 VAC
M24863
POWER WITH 24 VAC OR 120/240 VAC AT THE APPROPRIATE TERMINAL BLOCK.
24 VAC POWER TERMINAL BLOCK.
1
2
T775 APPLICATIONS
Water Source Heat Pump Loop Water
Controller – T775B
Application Description
Water is circulated in a loop to remove waste heat and to
provide cooling from a multiple heat pump system. In this
example, the T775B controls heating and cooling systems to
maintain the loop water temperature between preset upper
and lower limits. Alarms are sounded to annunciate
abnormally high or low water temperatures.
NOTE: T775R reset models can also be used in this
application.
Sensor Designation
This device application only requires one sensor. Sensor A is
mounted in a well, located in the main loop water line, before
the water source heat pump take-offs.
Operation
In this example, if the loop water temperature drops to 55° F
(13° C), heat is added to the system by the boiler (Relay 1)
until it reaches the setpoint. If the temperature drops further,
Relay 2 sounds the low temperature alarm at 54° F (12° C).
If the loop water temperature rises to 95° F (35° C), Relay 3
brings on cooling. If the temperature rises to 96° F (36° C),
Relay 4 powers the high temperature alarm.
NOTE: If no alarms are present, relays 2 and 4 may be used
as additional heating and cooling relays.
Setpoints may differ according to equipment manufacturers.
See their recommendations.
IMPORTANT
After the desired value is selected, be sure to press
the or or HOME button in order to save that
value in the controller’s memory.
Wiring
All output relays should have a common power wiring source,
which may or may not be the same as the T775 power wiring.
See Fig. 3.
Programming Example
Relay 1: Enables boiler circuit
Program for:
—Heat
— Setpoint = 65° F (18° C)
— Differential = 10° F (-12° C)
Relay 2: Low temperature alarm circuit
Program for:
—Heat
— Setpoint = 55° F (13° C)
— Differential = 1° F (-17° C)
Relay 3: Enables cooling circuit (heat extraction)
Program for:
—Cool
— Setpoint = 85° F (29° C)
— Differential = 10° F (-12° C)
Relay 4: High temperature alarm circuit
Program for:
—Cool
— Setpoint = 95° F (35° C)
— Differential = 1° F (-17° C)
Fig. 3. T775B wiring — loop water controller.
63-7147—05 8
T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
Chiller – T775B
Application Description
As the water temperature in the sump rises, the T775B
sequentially cycles on the spray pump valve and two relays of
fans. If the water temperature in the sump drops below 40° F
(4° C), the T775B energizes a sump dump drain valve to
prevent system freeze up.
NOTE: T775R reset models can also be used in this
application.
Sensor Designation
This device application only requires one sensor. Sensor A is
sensing sump water temperature.
Operation
In this example, the sump water temperature rises above the
Cooling Relay 1 setpoint plus differential 65° F (18° C) to bring
on the spray pump valve. If the temperature continues to rise,
Cooling relays 2; 70° F (21° C) and 3; 75° F (24° C) energize
the evaporation fans as needed.
If the sump water temperature drops below 40° F (4° C)
(setpoint minus differential), the sump water freeze up
protection is provided by energizing Heating Relay 4.
Programming Example
Relay 1: Controlling spray water pump and/or valve
Program for:
—Cool
— Setpoint = 60° F (16° C)
— Differential = 5° F (12° C)
Relay 2: Controlling fan # 1
Program for:
—Cool
— Setpoint = 65° F (18° C)
— Differential = 5° F (12° C)
Relay 3: Controlling fan # 2
Program for:
—Cool
— Setpoint = 70° F (21° C)
— Differential = 5° F (12° C)
Relay 4: Controlling dumping of sump at freeze condition
Program for:
—Heat
— Setpoint = 50° F (10° C)
— Differential = 10° F (-12° C)
IMPORTANT
After the desired value is selected, be sure to press
the or or HOME button in order to save that
value in the controller’s memory.
Wiring
All output relays should have a common power wiring source,
which may or may not be the same as the T775 power wiring.
See Fig. 4.
SENSOR A
(SUMP WATER)
T
T
T775B
L1
(HOT)
L2
SUMP
DUMP
VALV E
SPRAY
PUMP
VALV E
FAN
#1
FAN
#2
POWER WITH 24 VAC OR 120/240 VAC AT THE APPROPRIATE
1
TERMINAL BLOCK.
2
24 VAC POWER TERMINAL BLOCK.
Fig. 4. T775B wiring — chiller.
2
C
+
RELAY
4
NC
NO
C
NO
NC
RELAY
1
1
120
COM
120 VAC
240
M24864
RELAY
3
NC
C
NO
C
NO
C
NC
RELAY
2
9 63-7147—05
T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
Chiller, Rotary Compressor – T775B
Application Description
The T775B is controlling the discharge water temperature of a
rotary compressor. The T775B provides an optional low
temperature or low pressure cut-out circuit.
NOTE: T775R reset models can also be used in this
application.
Sensor Designation
This device application only requires one sensor. Sensor A is
sensing discharge water and controls 1 or 2 compressors.
Operation
In this example, the cooling capacity of a Rotary Compressor
is controlled by a slide valve, which when moved towards
open or closed allows more or less refrigerant into the
compressor. Open and Closed solenoid valves position this
slide valve. The T775B is configured such that two relays are
used to position a single slide valve in a floating mode by
controlling the respective solenoid valves. Capacity of rotary
compressors may also be controlled by variable speed drives,
not covered here.
Programming Example
Relay 1: Compressor #1 controlling the Close solenoid valve
Program for:
—Cool
— Setpoint = 52° F (11° C)
— Differential = 2° F (-17° C)
Relay 2: Compressor #1 controlling the Open solenoid valve
Program for:
—Cool
— Setpoint = 56° F (13° C)
— Differential = 2° F (-17° C)
Relay 3: Compressor #2 controlling the Close solenoid valve
Program for:
—Cool
— Setpoint = 56° F (13° C)
— Differential = 2° F (-17° C)
Relay 4: Compressor #2 controlling the Open solenoid valve
Program for:
—Cool
— Setpoint = 60° F (16° C)
— Differential = 2° F (-17° C)
IMPORTANT
After the desired value is selected, be sure to press
the or or HOME button in order to save that
value in the controller’s memory.
Wiring
All output relays should have a common power wiring source,
which may or may not be the same as the T775 power wiring.
See Fig. 5.
(DISCHARGE WATER)
SENSOR A
T
T
T775B
2
C
+
RELAY
4
NC
C
NO
NO
C
NC
RELAY
1
COOL MODE COMPRESSOR #1
OPEN SOLENOID
ENERGIZED
NULL
CLOSE SOLENOID
ENERGIZED
COOL MODE COMPRESSOR #2
OPEN SOLENOID
ENERGIZED
NULL
CLOSE SOLENOID
ENERGIZED
RELAY
3
NC
C
NO
RELAY
NO
C
NC
(HOT)
L1
L2
COMPRESSOR
#2
OPEN
SOLENOID
COMPRESSOR
#1
CLOSE
SOLENOID
COMPRESSOR
#1
OPEN
SOLENOID
COMPRESSOR
#2
CLOSE
SOLENOID
1
POWER WITH 24 VAC OR 120/240 VAC AT THE APPROPRIATE
TERMINAL BLOCK.
2
24 VAC POWER TERMINAL BLOCK.
T
E
M
P
E
R
A
F
T
A
U
L
R
L
E
T
E
M
P
E
R
A
F
T
A
U
L
R
L
E
2°
56°
2°
52°
2°
60°
2°
56°
Fig. 5. T775B wiring — chiller, rotary compressor.
1
120 VAC
120
240
COM
2
R
T
I
E
S
M
E
P
E
R
A
T
U
R
E
R
T
I
E
S
M
E
P
E
R
A
T
U
R
E
M24865
63-7147—05 10
T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
Cooling Tower Control – T775B2040
Application Description
The T775B2040 is controlling a cooling tower fan, based on
two sensor inputs, to control the low and high fan speeds and
provide cold weather shutdown.
NOTE: T775R2001 reset model can also be used in this
application.
Sensor Designation
This device application requires two sensors:
• Sensor A is sensing the sump temperature.
• Sensor B is sensing the outside air temperature.
Operation
As the sump temperature increases, the low fan speed is
energized by Relay 1. On further increase in temperature,
Relay 2 closes, which energizes the high fan speed and shuts
off the low fan speed. Relay 3 provides cold weather
shutdown of the fan. Relay 3 is wired in series with the
common wire of relays 1 and 2, so when Relay 3 breaks at
55° F (13° C), power to the fan is interrupted.
Programming Example
Optional: In Setup, label sensors A and B as desired.
Relay 1: Control to the fan low speed based on the sump
temperature.
Program for:
— Setpoint = 65° F (18° C)
— Differential =5° F (12° C)
—Cool
— Sensor A
Wiring
All output relays should have a common power wiring source,
which may or may not be the same as the T775 power wiring.
See Fig. 6.
SENSO R B - OUTSI DE AIR T EMPER ATURE
SENSO R A - SUMP T EMPER ATURE
T
T
T
T775B2040
T
2
120
COM
240
NO
NC
1
120 VAC
COM
FAN
NO
COM
C
+
RELAY
4
NC
NO
C
NO
NC
RELAY
1
RELAY
3
NC
C
NO
C
NO
C
NC
RELAY
2
Relay 2: Control to the fan high speed based on the sump
temperature
Program for:
— Setpoint = 70° F (21° C)
— Differential = 5° F (12° C)
—Cool
— Sensor A
Relay 3: Control to the fan cutoff based on the outside air
temperature
Program for:
— Setpoint = 55° F (13° C)
— Differential = 1° F (12° C)
—Cool
— Sensor B
IMPORTANT
After the desired value is selected, be sure to press
the or or HOME button in order to save that
value in the controller’s memory.
IMPORTANT
By programming the Relay 3 setpoint at 55° F (13°
C), the T775 is wired to cutoff power to the cooling
fan. Once the outside air temperature rises above
55° F (13° C), relays 1 and 2 control the fan speed
based on their setpoints for Sensor A Sump.
MOTOR COMMON
LOW SPEED WINDING
HIGH SPEED WINDING
1
POWER WITH 24 VAC OR 120/240 VAC AT THE APPROPRIATE
TERMINAL BLOCK.
2
24 VAC POWER TERMINAL BLOCK.
M25513
Fig. 6. T775B2040 wiring for cooling tower control.
Device Checkout
The T775B performance can be checked out to determine if
proper operation exists.
For example, when the outside air temperature is at 55° F
(13° C) or less, the fan should be off. Use the alternate Home
screens to verify that the fan is on or off, based on the outside
air temperature (Sensor B).
NOTE: The alternate Home screens do not show live
updates of the sensor temperature. They show the
temperature only at the moment the button is
pressed.
1. From the Home screen, use the button to verify
the setpoint temperature for Relay 3.
2. Then, press the HOME button to view the actual
outside air temperature (Sensor B).
11 63-7147—05
T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
Time-based Control of Fan, Pump,
etc.
— T775 (all models)
Application Description
In this example, the T775B is able to energize a fan, pump,
lights, economizer, or other device based on a daily time
schedule rather than based on temperature.
Operation
In this example, one relay will energize at 6:00 a.m. and deenergize at 6:00 p.m. daily to operate a fan, pump, or anything
at all.
Configuration Example
Place a 1,000 Ohm resistor at Sensor B (to simulate a
constant 32° F (0° C) temperature reading).
Wire the device to the normally open contacts on a relay.
Relay 1 is used in this example. See Fig. 7
Programming Example
Program in Setup for:
— Outputs
Options
Use Scheduler = YES
NOTE: Keep in mind that if the scheduler is energized, all
relays will follow the time schedule. If you do not
want some outputs to go into a setback mode,
choose Scheduler = NO for those outputs, or
program the setpoint and setback to the same
temperature.
IMPORTANT
After the desired value is selected, be sure to press
the or or HOME button in order to save that
value in the controller’s memory.
Wiring
All output relays should have a common power wiring source,
which may or may not be the same as the T775 power wiring.
1
T
T775B
T
T
SENSOR B
T
Program in Schedule for:
— Options
Set Date = current date
1
Set Time = current time
Set Daylight = YES or NO
— Mon-Fri
E1 Setpoint = Setpoint
E1 Time = 06:00 AM
E2 Setpoint = Setback
E2 Time = 6:00 PM
Relay 1: Control the device (fan, pump, etc.)
Program for:
— Setpoint = 0° F (-17° C)
— Differential = 1° F (-17° C)
— Sensor = Sensor B
— Setback =100° F (38° C)
— Action = Cool
Now the relay will close at 6:00 a.m. and open at 6:00 p.m.,
daily.
1
The date must be set before the time is set.
2
COM
3
120 VAC
240
L2
L1
(HOT)
C
+
RELAY
4
NC
C
FAN,
PUMP,
LIGHTS,
ECONOMIZER,
OR
OTHER DEVICE
INSERT 1000 OHM RESISTOR.
1
24 VAC POWER TERMINAL BLOCK.
2
POWER WITH 24 VAC OR 120/240 VAC AT THE APPROPRIATE
3
TERMINAL BLOCK.
NO
RELAY
NO
C
NC
1
RELAY
3
NC
C
NO
RELAY
NO
NC
120
C
2
Fig. 7. T775B wiring for time-based fan, pump or other
device.
M28021
63-7147—05 12
T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
Damper or Valve Modulation – T775M
or T775R
Application Description
In this example, a T775M is controlling an actuator, based on
temperature input, to modulate a damper or valve.
Sensor Designation
This device application requires one sensor.
• Sensor A is sensing outside temperature
NOTE: Sensor A or Sensor B can be used in this
application.
Programming Example
Program in Setup for:
— Modulating Output (MOD) 1:
Type = 2-10V (or whatever output signal is preferred)
Minimum Output % = 0% (range is 0-100%)
Modulating Output 1:Enable actuator circuit
Program for:
— Setpoint = 120° F (49° C)
— Throttling Range = 10° F (-12° C)
— Sensor = Sensor A
— Heat or Cool
IMPORTANT
After the desired value is selected, be sure to press
the or or HOME button in order to save that
value in the controller’s memory.
MS75xx
SPRING RETURN
DIRECT COUPLED ACTUATOR (DCA)
WIRING
STRIP
1
2
3
4
5
MOD 1
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
B
R
W
L1
(HOT)
1
L2
C
–
+
S
V
T
T
Fig. 8. T775M wiring — damper modulation
(2-10 Vdc shown).
SENSOR A
T775M
M24881A
Wiring
See Fig. 8 and 9 for wiring connections for the T775M with
examples of an MS75xx actuator and an ML7425 valve
actuator.
ML7425
SPRING RETURN
ACTUATOR
VALV E
WIRING
STRIP
F
+
–
T2
L1
(HOT)
L2
1
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
T1
O1
O2
TS
MOD 1
B
–
R
+
W
Fig. 9. T775M wiring — valve modulation (2-10 Vdc
shown).
C
S
V
T
T
SENSOR A
T775M
M28042
13 63-7147—05
T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
M24871
SENSOR B
SP MAX A1
(BOILER MAX)
SP MIN A2
(BOILER MIN)
200
140
10
RELAY 2
SETPOINT
OFFSET -10°F
190
20
30 40 50 60
70
°F80
150
160
170
210
220
180
°F
RESET B1
(OUTSD MIN)
RESET B2
(OUTSD MAX)
S
E
N
S
O
R
A
RELAY 1
SETPOINT
Hot Water Reset – T775R
Application Description
The T775R is controlling the boiler water temperature with two
stages (relays), based on outside temperature using a reset
curve and an offset for Relay 2.
Sensor Designation
This device application requires two sensors.
• Sensor A is sensing hot water discharge temperature of
the boiler.
• Sensor B is sensing outside air temperature
Operation
In this example, when the outside temperature reaches
70° F (21° C), the desired water temperature of the boiler is
160° F (71° C). Likewise, when the outside temperature drops
to 20° F (-7° C), the hot water temperature needs to be
210° F (99° C). See Fig. 10.
Fig. 10. Hot water reset curve.
Programming Example
Program in Setup:
Press and hold the MENU button for 5 seconds to enter
Setup mode. Select the Outputs menu, and then select:
—MOD 1
— # Relays = 2
— Relay 1 → Reset = YES-BOILER
— Relay 2
Relay 1: Control to the discharge water temperature
Program for: (Refer to the reset curve in Fig. 10.)
— Boiler Max = 210° F (99° C)
— Outside Min = 20° F (-7° C)
— Boiler Min = 160° F (71° C)
— Outside Max = 70° F (21° C)
— Differential = 20° F (-7° C)
— Sensor A
—Heat
Relay 2: Control to the discharge water temperature
Program for:
— Setpoint Offset = -10° F (-12° C) (See Fig. 11)
— Sensor A
—Heat
63-7147—05 14
→ Reset = YES-BOILER
→ Reset = YES-BOILER
MENU
PROGRAM
RELAY 2
OFFSET
-10
ENTER
SETPOINT
OFFSET
FOR
RELAY 2
o
F
M24321
PROGRAM
RELAY 2
MENU
PROGRAM
RELAY 2
OFFSET
DIFFRNTL
HEAT/COOL
SETBACK
EXIT
Fig. 11. Program mode — Relay 2 offset.
IMPORTANT
After the desired value is selected, be sure to press
the or or HOME button in order to save that
value in the controller’s memory.
IMPORTANT
By programming the boiler setpoint at 210° F (99° C)
the T775 has established 210° F (99° C) as the
highest operating point that will be allowed when the
outside temperature falls below 20° F (-7° C). As the
outside temperature increases above 20° F (-7° C),
the boiler will be reset downward per the reset ratio
until it reaches the minimum setpoint, 160° F.
Assuming an outside temperature of 20° F (-7° C), Fig. 12
describes the actions of relays 1 and 2 to control the boiler
temperature. As the boiler temperature falls below 210° F
(99° C), Relay 1 activates (Relay 1 Differential is 20° F (-7° C),
so relay closes at 190° F (88° C). If Relay 1 cannot raise the
boiler temperature and the boiler temperature continues to fall
to 180° F °, Relay 2 activates (Relay 2 differential is 20° F
(-7° C) 180° to 200° F (82° to 93° C). When the boiler is able
to reach 200° F (93° C), then Relay 2 deactivates and Relay 1
remains active until the temperature reaches 210° F (99° C).
.
BOILER DISCHARGE
TEMPERATURE
RELAY 1 OFF
RELAY 2 OFF
RELAY 1 ON
RELAY 2 ON
M24877
RELAY 1
DIFFERENTIAL
RANGE
DIFFERENTIAL
RELAY 2
RANGE
210°
200°
190°
180°
Fig. 12. Relay actions.
NOTE: The hot water reset application continues on the next
page.
T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
Hot Water Reset (continued)
Wiring
All output relays should have a common power wiring source,
which may or may not be the same as the T775 power wiring.
See Fig. 13.
(HOT WATER DISC HARG E)
L1
(HOT)
L2
SENSOR A
SENSOR B
(OUTSIDE AIR)
HOT
WATER
BOILER #1
HOT
WATER
BOILER #2
2
C
+
RELAY
4
NC
NO
C
NO
NC
RELAY
1
T
T
T
T775R
T
1
120
COM
120 VAC
240
RELAY
3
NC
C
NO
C
NO
C
NC
RELAY
2
Device Checkout
The T775 performance can be checked out to determine if
proper operation exists.
For example, when the outside air temperature is at 50° F
(10° C), the boiler setpoint temperature should be 180° F
(82° C). See Fig. 14. Use the alternate Home screens to
check that the effective setpoint is adjusting correctly based
on the outside air temperature (Sensor B).
NOTE: The alternate Home screens do not show live
Fig. 14. Boiler discharge temperature setpoint vs. outside
updates of the sensor temperature. They show the
temperature only at the moment the button is
pressed.
1. From the Home screen, use the button to verify
the setpoint temperature for each output.
2. Then, press the HOME button to view the actual
outside air temperature (Sensor B).
BOILER SETPOINT
TEMPERATURE
210°
190°
180°
170°
160
OUTSIDE AIR
TEMPERATURE
20°
30°200°
40°
50°
60°
70°
M24873
temperature.
POWER WITH 24 VAC OR 120/240 VAC AT THE APPROPRIATE
1
TERMINAL BLOCK.
2
24 VAC POWER TERMINAL BLOCK.
Fig. 13. T775R wiring — hot water reset.
M24872
15 63-7147—05
T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
Chilled Water Reset – T775R
Application Description
The T775R is controlling the chiller water temperature, based
on outside temperature using a reset curve.
Multiple stages can also be controlled by using an offset from
the main setpoint for the subsequent relay outputs. When
enabling multiple stages for reset, each stage can have its
own programmable offset from Relay 1 (stage 1).
Sensor Designation
This device application requires two sensors.
• Sensor A is sensing the water temperature of the chiller.
• Sensor B is sensing outside air temperature.
Operation
In this example, when the outside temperature reaches 90° F
(32° C), the desired water temperature of the chiller is
45° F (7° C). Likewise, when the outside temperature drops to
70° F (21° C), the chilled water temperature needs to be 60° F
(16° C).
.
SP MAX A1
SENSOR A
(CHILLER)
°F
65
60
55
50
Relay 1: Control to the chilled water temperature
Program for: (Refer to the reset curve in Fig. 15.)
— Setpoint Max A1 (Chiller) = 60° F (16° C)
— Reset B1 (Outside Min) = 70° F (21° C)
— Setpoint Min A2 (Chiller) = 45° F (7° C)
— Reset B2 (Outside Max) = 90° F (32° C)
— Differential = 10° F (-12° C)
—Cool
IMPORTANT
After the desired value is selected, be sure to press
the or or HOME button in order to save that
value in the controller’s memory.
IMPORTANT
By programming the Chiller setpoint at 45° F (7° C)
the T775 has established 45° F (7° C) as the lowest
operating control point that will be allowed during
reset with the above conditions satisfied.
Wiring
All output relays should have a common power wiring source,
which may or may not be the same as the T775 power wiring.
SENSOR B
(OUTSIDE AIR)
SENSO R A (CHILL ED WATER)
T
T
T
T775R
T
SP MIN A2
45
40
65 95
RESET B1
(OUTSD MIN)
70
75 80 85
90
RESET B2
(OUTSD MAX)
SENSOR B (OUTSIDE AIR)
Fig. 15. Chiller reset curve.
Programming Example
Program in Setup:
Press and hold the MENU button for 5 seconds to enter
Setup mode. Select the Outputs menu, and then select:
—MOD 1
— # Relays = 1
— Relay 1 → Reset = YES-OTHER
→ Reset = YES-OTHER
°F
M24874
2
C
+
L2
L1
(HOT)
RELAY
4
NC
C
NO
CHILLER
POWER WITH 24 VAC OR 120/240 VAC AT THE APPROPRIATE
1
TERMINAL BLOCK.
2
24 VAC POWER TERMINAL BLOCK.
NO
NC
RELAY
1
C
RELAY
NC
C
NO
Fig. 16. T775R wiring — chilled water reset.
3
NO
RELAY
1
120 VAC
120
240
COM
C
NC
2
M24875
63-7147—05 16
T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
Chilled Water Reset (continued)
Device Checkout
The T775 performance can be checked out to determine if
proper operation exists.
For example, when the outside air temperature is at 80° F
(27° C), the chiller water temperature should be 52.5° F
(11° C). See Fig. 17. Use the alternate Home screens to
check that the effective setpoint is adjusting correctly based
on the outside air temperature (Sensor B).
NOTE: The alternate Home screens do not show live
updates of the sensor temperature. They show the
temperature only at the moment the button is
pressed.
1. From the Home screen, use the button to verify
the setpoint temperature for each output.
2. Then, press the HOME button to view the actual
outside air temperature (Sensor B).
CHILLED WATER
SETPOINT TEMPERATURE
60°
56.25°
52.5°
48.75°
45°
Fig. 17. Chiller setpoint vs. outside temperature.
OUTSIDE AIR
TEMPERATURE
70°
75°
80°
85°
90°
M24876
Multi-Stage Boiler Control (No Reset)
– T775P
Application Description
The T775P is providing multistage boiler control based on the
boiler's discharge water temperature. The T775P uses the
fourth output relay to energize the primary pump.
Sensor Designation
This device application requires two sensors.
• Sensor A is sensing discharge water and is used to control
3 boiler stages.
• Sensor C is sensing the return water.
NOTE: Control can be to either Sensor A or C.
Operation
In this example, as the heating load increases, additional
stages of heat will cycle ON as the boiler water temperature
decreases. The T775P will stage three boilers to provide
sufficient heating. (See Fig. 18.) The primary circulating pump
energizes whenever any stage is energized.
Programming Example
Program in Setup:
Press and hold the MENU button for 5 seconds to enter
Setup mode. Select the Outputs menu, and then select:
— # Stages = 3 (T775 assigns pump to Relay 4)
— Options
Seconds = 0 to 3,600 (default is 0)
— Options → WWSD = YES or NO
Temperature = 30 to 100° F (-1 to 38° C)
— STG4/Pump: (Relay 4 controls the pump output)
Enable = YES
Exercise = YES or NO
Prepurge = -300 to 300 seconds (default is 0)
Postpurge = 0 to 300 seconds (default is 0)
NOTES:
1. A positive Prepurge time causes the pump to
2. The Postpurge time causes the pump to run for
Return to the Setup menu, and select Alarms:
— High Alarm = YES
— High Limit = 220° F (93° C)
NOTE: This model has Equal Runtime options, which can be
→ On Delay and Off Delay:
energize before the first stage energizes.
A negative time causes the pump to energize
after the first stage energizes.
the set number of seconds after the last stage
de-energizes.
configured with the Lead Lag output option in Setup.
Stages 1-3: Control to the discharge water temperature
Program for:
— Setpoint = 200° F (93° C)
— Throttling Range = 18° F (-8° C)
— Sensor A
—Heat
IMPORTANT
After the desired value is selected, be sure to press
the or or HOME button in order to save that
value in the controller’s memory.
17 63-7147—05
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