PRO1 IAQ T855SH Universal Programmable Thermostat – 2H/3C Conv, 5H/3C Heat Pump

Description

Overview

The PRO1 IAQ T855SH Universal Programmable Thermostat is a powerful, flexible comfort control solution engineered for both residential and light commercial HVAC applications. Supporting up to 2 stages of heat and 3 stages of cool on conventional systems — or up to 5 stages of heat and 3 stages of cool on heat pump systems — the T855SH is built to handle virtually any installation a contractor will encounter. Choose between 7-day, 5-1-1, or non-programmable scheduling, and power the unit via hardwire (18–30 VAC, NEC Class II) or 2 AA alkaline batteries for maximum installation flexibility.

Indoor Air Quality & Comfort Control

Built for serious IAQ performance, the T855SH features integrated humidity and dehumidity control, ventilation control, IAQ fan settings, and Advanced Pre-Occupancy Purge to keep indoor air fresh and healthy before occupied periods. Auto changeover, customizable staging logic, and adjustable heat and cool swing (0.2°F to 2.0°F) deliver precise, efficient comfort in any environment. Selectable two or four occupancy/unoccupancy time periods make it equally effective in offices, retail spaces, and single-family homes.

Sensor & Dual-Fuel Compatibility

Pair the T855SH with the optional R250S outdoor sensor to enable dual-fuel balance points and outdoor temperature display. For multi-zone averaging, connect up to 16 R251S indoor remote sensors to deliver consistent comfort across large or complex spaces.

Display & User Interface

A large 8 sq. in. display with blue backlight and glow-in-the-dark light button ensures easy operation in any lighting condition. Partial and full keypad lockout, adjustable setpoint limits, and Summer Away mode protect settings in rental properties and commercial installations.

Features

• Universal application: up to 2H/3C conventional or up to 5H/3C heat pump
• Flexible programmability: 7-day, 5-1-1, or non-programmable operation
• Dual power options: hardwire (18–30 VAC, NEC Class II, 50/60 Hz) or 2 AA alkaline batteries
• Humidity and dehumidity control with ventilation control and IAQ fan settings
• Advanced Pre-Occupancy Purge to freshen indoor air before occupied periods
• Dual-fuel capable with R250S outdoor sensor for balance point control
• Supports up to 16 R251S indoor remote sensors for temperature averaging
• Auto changeover — automatic heating/cooling switching (not available in PTAC mode)
• Customizable staging logic for optimal comfort and efficiency
• Large 8 sq. in. display with blue backlight and glow-in-the-dark light button
• Selectable two or four occupancy/unoccupancy time periods
• Adjustable heat and cool swing: 0.2°F to 2.0°F for precise comfort tuning
• Adjustable setpoint limits — ideal for rentals, offices, and commercial spaces
• Summer Away mode for energy savings during extended absences
• Partial or full keypad lockout to prevent unauthorized changes
• Easy-access battery compartment for quick, tool-free battery replacement

Specifications

• Display range: 41°F to 95°F (5°C to 35°C)
• Control range: 44°F to 90°F (7°C to 32°C)
• Display accuracy: +/- 1°F
• Terminals: Rc, Rh, G, Y, Y2, S1, S2, C, O, B, W/E, W2
• Load rating: 1 amp per terminal, 1.5 amp maximum combined
• Operating ambient: 32°F to 105°F (0°C to 41°C)
• Operating humidity: 90% non-condensing maximum
• Mounting: wall or junction box
• Dimensions: 4.7″W x 4.4″H x 1.1″D (119mm W x 112mm H x 28mm D)
• Warranty: 5-year limited warranty

Applications

Single-family homes, multi-family housing, light commercial buildings, offices, retail spaces, churches, and any application requiring multi-stage HVAC control, IAQ management, or remote sensor averaging.