White Rodgers 1F90-371 User Manual

The White Rodgers 1F90-371 is a programmable electronic digital thermostat from the Comfort-Set III series for single-stage heating/cooling systems, including gas, oil, electric, hot water/steam, millivolt, and single-stage heat pump. It features 5+2 or 5+1+1 day programming, microcomputer technology for precise control, automatic changeover, and energy-saving features like Energy Management Recovery (EMR). Powered by 24 VAC system; compatible with systems up to 1.5A total load. Below are the key specifications, installation, operation, programming, and troubleshooting instructions.

Preparations

Assemble tools: hand or power drill with 3/16 inch drill bit (if needed), flat blade screwdriver, wire cutter/stripper, level. Shut off electricity at main fuse box until installation complete. Label wires before disconnecting. This thermostat is for 24V systems only; not for line voltage. Install away from drafts, direct sunlight, or heat sources for accurate sensing.

WARNING! Failure to read and follow all instructions carefully before installing or operating this control could cause personal injury and/or property damage. Save these instructions.

Description

The thermostat uses solid-state microcomputer technology to provide precise time/temperature control. It offers flexibility to design heating and cooling programs that fit personal needs. Adaptable to most 24 Volt residential forced air, hydronic (hot water or steam), millivolt, electric heat, zone and single-stage heat pump systems. Features large lighted LCD display alternating between room temperature and time, up/down arrows for adjustment, SYSTEM switch (HEAT/OFF/COOL/AUTO), FAN switch (ON/AUTO), O/B for heat pumps.

Applications: Gas/Oil/Electric Heat: Yes; Heat Pump Single Stage: Yes; Heat Only: Yes; Cool Only: Yes; Millivolt: Yes; Hydronic: Yes.

Precautions

CAUTION! To prevent electrical shock/equipment damage, disconnect power at main fuse/circuit breaker until installation complete. Label wires prior to disconnection.

WARNING! Do not use on circuits exceeding 30 VAC 50/60 Hz (1.5A max total); higher voltage damages control/causes shock/fire. Do not short terminals to test; incorrect wiring causes injury/property damage. Conform to NEC Class II circuits. Do not operate cooling below 50°F (compressor damage).

ATTENTION! This product does not contain mercury but may replace one that does. Dispose properly; refer to recycling resources.

Specifications

• Electrical: 17-30 VAC 50/60 Hz, NEC Class II; Terminal Load 1.5A max total (all terminals).
• Setpoint Range: 45°F to 99°F (7°C to 37°C).
• Operating Ambient: 32°F to 110°F (0°C to 43°C).
• Humidity: 90% non-condensing max.
• Shipping: -4°F to 131°F (-20°C to 55°C).
• Dimensions: Not specified; standard wall-mount.
• Programming: 5+2 or 5+1+1 day (1F90-371).
• Other: Compressor lockout 5 min; Filter timer 0-1950 hrs; Supports up to 3 indoor/1 outdoor remote sensors.

Removing Old Thermostat

A standard heat/cool thermostat consists of three basic parts: 1) Cover; 2) Base; 3) Subbase. Label each wire with terminal designation before disconnecting. Disconnect wires one at a time; do not let fall into wall.

Installation

Remove old thermostat. Mount new base level on wall, connect wires to terminals. For single transformer systems, install red jumper between RH and RC. Push excess wire into wall, secure base, attach thermostat body. Power up and configure.

Wiring Diagrams

Terminal Designations: RH/RC (power), W (heat), Y (cool/compressor), G (fan), O/B (changeover for heat pump).

Single Stage Heat/Cool: RH to hot, RC to hot (jumper RH-RC), W to heat relay, Y to compressor, G to fan.

Heat Only: Omit Y.

Cool Only: Omit W.

Heat Pump Single Stage: Y to compressor, O/B to changeover, W to aux heat if needed.

CAUTION! RED jumper wire must be connected between RH and RC for single transformer systems.

Check Operation

Restore power. Set SYSTEM to HEAT/COOL, FAN to ON/AUTO, adjust setpoint to test.

Fan Operation

1. FAN ON: Blower runs continuously.
2. FAN AUTO: Blower runs on call for heat/cool.

Heating System

1. SYSTEM HEAT.
2. Setpoint above room temp: Heat activates.
3. Setpoint below: Heat stops.

Emergency System

Not applicable for single-stage non-heat pump; for heat pump, use aux heat.

Cooling System

CAUTION! Do not operate below 50°F.

1. SYSTEM COOL.
2. Setpoint below room temp: Cool activates (5-min delay first time).
3. Setpoint above: Cool stops.

Operating Features

• Home Screen: LCD shows time/temp, alternates; icons for system on, hold, filter, etc.
• Key Features: Automatic changeover, preprogrammed schedules, short-cycle protection, programmable fan, filter indicator, temporary override, vacation hold, remote sensing, daylight savings, power loss recovery.
• Compressor Protection: 5-min lockout.
• Remote Sensors: Up to 3 indoor, 1 outdoor; averages or selects.
• Range Limits: Heat/Cool 45-99°F.

Programming

5+2 or 5+1+1 day; 4 periods (MOR/DAY/EVE/NHT). Factory preprogrammed; press PROGRAM + RUN to start.

1. Set Time/Day: Press PROGRAM, TIME ± for hour/min, DAY for day.
2. Program: Select HEAT/COOL, press PROGRAM for period, TIME/TEMP ± to set.
3. Copy: Hold COPY to duplicate day/period.
4. Review: Press PROGRAM to cycle through.
5. Run: Press RUN.
6. Hold: Press HOLD for permanent; VACATION for timed hold.

Factory Heat: 6AM 70°F, 8AM 62°F, 5PM 70°F, 10PM 62°F. Cool: 6AM 78°F, 8AM 85°F, 5PM 78°F, 10PM 82°F.

Installer Configuration

Press PROGRAM + DOWN arrow for 5 seconds to enter menu. Use UP/DOWN to adjust, PROGRAM to advance.

Troubleshooting