The White Rodgers Type-152 is a mechanical line voltage thermostat designed for controlling heating equipment operating on line voltage with heavy electrical loads, such as unit heaters, boilers, furnaces, and electric heaters. It features an internal dial for tamper-proof operation, requiring a special wrench for adjustment, and is suitable for public places to prevent unauthorized changes. The thermostat has a 45°F to 80°F range and a 3°F differential. Below are the key specifications, installation, operation, and troubleshooting instructions.
Assemble tools: flat blade screwdriver, wire cutter/stripper, level, special wrench for tamper-proof case. Shut off electricity at main fuse box until installation complete. Label wires before disconnecting. This thermostat is for line voltage systems (240/277 VAC); not for low voltage. Install in a location with free air circulation, away from outside walls, windows, doors, strong light, or false heat sources like steam lines. For unit heaters, position where return air flows over thermostat or in typical occupied space.
WARNING! These controls must be installed by a qualified installer. 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 Type-152 is a mechanical thermostat specifically designed for controlling heating equipment operating on line voltage with heavy electrical loads. It is suitable for operation of unit heaters, boilers, furnaces, electric heaters, or any similar application requiring a heavy-duty room thermostat. The thermostat features an internal dial for tamper-proof operation, preventing unauthorized temperature adjustments. A special wrench is required to remove the locked case from the mounting plate to change the temperature setting.
Applications: Electric Heating: Unit Heaters, Boilers, Furnaces, Electric Heaters; Voltage: 240/277 VAC; Heavy-Duty Loads; Tamper-Proof for Public Spaces.
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. This control is a precision instrument, and should be handled carefully. Rough handling or distorting components could cause the control to malfunction. This control has been accurately calibrated at the factory. Any attempt to calibrate this control will void the White Rodgers warranty.
WARNING! Do not use on circuits exceeding specified voltages. Higher voltages will damage control and could cause shock or fire hazard. All wiring must conform to local and national electrical codes and ordinances.
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.
To prevent electrical shock and/or equipment damage, disconnect electric power to system at main fuse or circuit breaker box until installation is complete. The mounting plate for this thermostat has two holes 3/16" apart for attaching the control on a standard switch box. For unit heaters, position A (return air flow) or B (typical occupied space) is recommended. Insert all wires into the wall opening, secure the mounting plate to the switch box with two screws, and attach the thermostat case to the mounting plate. Use the special wrench to remove the locked case for temperature adjustment if needed.
Terminal Designations: L1 (Hot), L2 (Line 2), Load to Heater.
240/277 VAC (Double Pole): Connect L1 to power hot, L2 to second hot or neutral, load to heater terminals. The internal dial setting opens contacts to turn off heat.
Schematic: POWER IN -- L1 Thermostat L2 -- HEATER LOAD -- POWER OUT.
CAUTION! All wiring must conform to local and national electrical codes. Do not use on inductive loads.
Restore power. Turn the dial so the fixed indicator points to the temperature at which it is desired to have the contacts open, thus turning off the heat. Confirm the system cycles on/off at the set differential.
Not applicable; heating-only thermostat without fan control.
Not applicable; use main power disconnect for emergency shutdown.
Not applicable; heating-only thermostat.
Non-programmable mechanical thermostat. Set desired temperature via internal dial using special wrench.
No electronic configuration; use temperature limiting pins to restrict dial range if available. Ensure tamper-proof locked case is secured. Adjust internal dial for initial setpoint using special wrench provided.
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| Heater not turning on | Dial set too low, power off, wiring issue. | Adjust dial above room temp using special wrench; check power and wiring. |
| Heater runs continuously | Stuck contacts, faulty bimetal. | Inspect for damage; replace thermostat. |
| Erratic operation | Loose wires, damaged sensing element. | Tighten connections; avoid distorting bimetal. |
| Overheating | Short cycle or load issue. | Check differential (3°F); ensure non-inductive load. |