Pro1 T855 Thermostat




✔   Universal
   3 Heat 2 Cool
   Battery or Hardwired
   7 Day 5/1/1 or NP 
   Set dual-fuel balance point with outdoor temperature sensor (R250S)
   Remote sensor compatable (R251S) for moving sensing location or temperature averaging 




  • 7 Day or 5/1/1 progammable

  • Auto Changeover

  • Easy menu driven programming

  • Intuitive wake, leave, return, sleep programming icons

  • 8 sq. inch display 

  • Blue backlight

  • Glow in the dark light button

  • Programmable fan

  • Electric or Gas configurable

  • Room temperature calibration adjustment

  • Separate heating and cooling swing (cycle rate) adjustments

  • Two and four occupancy/unoccupancy time periods available

  • Keypad lockout

  • Adjustable heating and cooling setpoint limits

  • 5 minute compressor delay protection (selectable on or off)

  • Filter change indicator(selectable on or off)

  • Simple private label badge system

  • Easy wire color coded terminal blocks

  • Universal sub-base

  • Mounts on wall or junction box

  • Advanced pre-occupancy purge and IAQ fan control

  • Set dual-fuel balance point with outdoor temperature sensor (R250S)

  • Remote sensor compatable (R251S) for moving sensing location or temperature averaging

  • Partial and full keypad lockout



800 Family Brochure Pro1 Linecard


T855S Thermostat
The display range of temperature 41°F to 95°F (5°C to 35°C)
The control range of temperature 44°F to 90°F (7°C to 32°C)

Load rating

1 amp per terminal, 1.5 amp maximum all terminals combined
Display accuracy ± 1 °F 
Swing (cycle rate or differential) Heating is adjustable from 0.2°F to 2.0°F 
Cooling is adjustable from 0.2
°F to 2.0°F 
Power source 18 to 30 VAC, NEC Class II, 50/60 Hz for hardwire (common wire) 
Battery power from 2 AA Alkaline Energizer batteries 
Operating ambient

32° to +105° (O° to + 41°C) 

Operating humidity

90% non-condensing maximum

Dimensions of thermostat

4.7"W x 4.4"H x 1.1"D