The White Rodgers M100 is a mechanical thermostat designed for single-stage heat/cool systems, heat-only, cool-only, and millivolt applications. It features adjustable heat anticipator, level mounting for accuracy, and compatibility with Class II circuits. Below are the key specifications, installation, operation, configuration, and troubleshooting instructions.
Assemble tools: hand or power drill with 3/16 inch drill bit (if needed), flat blade screwdriver, wire cutter/stripper, spirit level or plumb bob and line. Shut off electricity at main fuse box until installation complete. Label wires before disconnecting. This thermostat is for low voltage systems; not for line voltage. Install away from drafts, direct sunlight, or heat sources for accurate sensing. Thermostat must be level to work properly.
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.
The M100 is a mechanical thermostat for single-stage systems, controlling heating and cooling based on temperature setting. Features adjustable heat anticipator for precise control matching primary heating control current. Mechanical dial or lever for setpoint adjustment.
Applications:
| System Type | Supported |
|---|---|
| Standard Heat/Cool (4/5 Wires) | Yes |
| Heat-Only Systems | Yes |
| Millivolt Heat-Only | Yes |
| Central Air Conditioning | Yes |
| Gas/Oil/Electric Furnaces | Yes |
| Hydronic Zone Heat (2/3 Wires) | Yes |
CAUTION! To prevent electrical shock/equipment damage, disconnect power at main fuse/circuit breaker until installation complete. Label wires prior to disconnection. If in doubt about wiring, consult qualified heating/air conditioning contractor. Installation and components must conform to Class II circuits per NEC code.
WARNING! Do not use on circuits exceeding ratings; higher voltage damages control/causes shock/fire. Do not short terminals to test. All wiring must conform to local/national codes.
A standard heat/cool thermostat consists of three basic parts: Cover (snap-on/hinge), Base (captive screws), Switching Subbase (mounting screws). Label each wire with terminal designation before disconnecting. Disconnect wires one at a time; do not let fall into wall. Note heat anticipator setting (.2, .4, .8, etc.) for reference.
Remove old thermostat. Loosen three screws to separate base from subbase. Mount subbase to wall/adaptor plate with mounting screws. Connect wires to corresponding terminals. Reattach base to subbase and install cover. Ensure level using spirit level or plumb bob/line. Keep area clear of wires.
Terminal Designations: R (hot), C (common), G (fan), Y (compressor), W (heat).
Standard Heat/Cool (4/5 Wires): R to hot, W to heat, Y to cool, G to fan, C common.
Heat-Only: R to hot, W to heat.
Millivolt: W to gas valve.
Hydronic System: W to zone valve, R to transformer via valve.
CAUTION! Match old thermostat configuration. Refer to equipment manuals for specifics.
Restore power. Set to HEAT/COOL, adjust setpoint to test.
CAUTION! Do not operate below 50°F.
Non-programmable mechanical thermostat. Set desired temperature via lever or dial.
Set heat anticipator to match old thermostat or primary control current (0.15-1.2A). Rotate contact arm to setting (.2, .4, .8, etc.). Ensure level installation.
| Anticipator Setting | Current Rating |
|---|---|
| .2 | 0.15-0.3A |
| .4 | 0.3-0.6A |
| .8 | 0.6-1.2A |
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| No Heat/No Cool/No Fan | Wiring, power, settings. | Check connections, power, settings. |
| Intermittent Heat | Anticipator mismatch. | Adjust anticipator. |
| Constant Run | Stuck relay, wiring. | Inspect wiring, relays. |
| Cycles Too Fast/Slow | Anticipator, load. | Adjust anticipator; check system. |
| Temp Swing Narrow/Wide | Not level, anticipator. | Level thermostat; adjust. |
| Setting/Thermometer Disagree | Calibration issue. | Recalibrate or replace. |