Honeywell T775 Series 2000, Application Manual

T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS

3

63-7147—05

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 sen-

sor 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.

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 termi-

nal 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

2

 power (i.e. 4, 9, 16, etc.).

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).

COMPATIBLE COMPONENTS

Temperature Sensors

1

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.

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

2

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