T775 APPLICATION TIPS
Q Does the T775 save programmed values if the power is
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
constant 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
installation 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
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
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
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 63-1318-01).
power (i.e. 4, 9, 16, etc.).
T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
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
• 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
H7625, H7635, and H7655 models (available in 2, 3, and 5%
RH accuracy) can be used.
Low Differential Pressure Sensors (T775U
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 29 and the T775U
installation Instructions, form 62-0255-01.)
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,
• Non-spring return models: ML4161, ML6174, ML7161,
ML7164, MN1010, MN6105, MN7505, MN8810