ML-45 Universal Defrost Thermostat For Sale

The Supco ML45 Defrost Thermostat is a bimetal disc temperature control designed for defrost cycles in refrigeration equipment (freezers, refrigerators, commercial coolers). Its primary role is to sense coil temperature during the defrost cycle and open the circuit once a set temperature is reached, protecting the defrost heater and system from overheating. ([link removed by ])

🔧 Construction & Design

• Thermostat Type: Single-pole single-throw (SPST) snap-action temperature switch — closes on cooling and opens on warming. ([link removed by ])

• Sensing Element: Bimetal disc — two metals laminated together that bend with temperature change to actuate the switch, offering durability and reliable repeatability in cycling. ([link removed by ])

• Body & Sealing: Moisture-resistant sealed metal case (with epoxy potting in some versions) to withstand damp and frost-prone environments inside evaporator compartments. ([link removed by ])

• Leads: Insulated lead wires for connection into defrost heater circuits (length varies by supplier).

🌡️ Temperature Performance

• Close Temperature (Cooling Side): ~ 25 °F (≈1.7 °C) — thermostat contacts close as temperature falls. ([link removed by ])

• Open Temperature (Defrost Side): ~ 45 °F (≈12.8 °C) — contacts open when temperature rises during defrost, stopping defrost heater power. ([link removed by ])

• Differential: ≈ 20 °F between open and close points, which provides a buffer to avoid rapid cycling around a single temperature point. ([link removed by ])

These set points are engineered so the thermostat only interrupts power once the evaporator is warmed adequately in defrost but doesn’t react to minor fluctuations during normal cooling operation.

⚡ Electrical Ratings

• Voltage: Designed primarily for 120 VAC / 240 VAC systems, making it compatible with both residential and light commercial applications (depending on specific wiring and equipment). ([link removed by ])

• Current Capacity:

  • Up to 10 A at 120 VAC

  • Up to 5 A at 240 VAC
    These ratings support typical defrost heaters and related loads in many refrigeration units. ([link removed by ])

• Due to the sealed construction and rapid contact separation, the switch handles resistive loads up to about 1200 W.

⚙️ Function in Refrigeration

In refrigeration systems, defrost thermostats like the ML45 are integrated in series with the defrost heater and defrost control circuit:

1. During a defrost cycle, the heater warms the frozen evaporator coil.

2. As temperature rises, the ML45’s bimetal element reacts and eventually reaches its open temperature (~45 °F).

3. At that point, the thermostat interrupts the heater circuit, preventing overheating once defrost is complete.

4. On cooling back down after the heater is off, the thermostat resets (closes) near its close temperature and is ready for the next cycle. ([link removed by ])

This cycle protects components and contributes to efficient frost control and energy use.

🧰 Typical Applications

• Household refrigerators and freezers

• Commercial coolers and ice machines

• Evaporator defrost circuits

• Compatible as an OEM or aftermarket replacement for various part numbers used by major appliance brands.

🛠️ Key Features SummaryFeatureDescriptionThermostat TypeSPST temperature switchTemperature RangeCloses ~25 °F, opens ~45 °FDifferential~20 °FVoltage Rating120 VAC / 240 VACCurrent Capacity10 A @120V, 5 A @240VSealingMoisture resistant sealed metal caseLead WiresInsulated leads for easy connection📌 Notes & Considerations

• Always verify the exact temperature specifications when replacing an existing thermostat, as similar models in the ML series may have slightly different set points.

• Ratings assume a resistive load; inductive loads (motors, etc.) may need precautions or a different part.

• Observe safety standards and disconnect power before Disclaimer

  For proper installation and safe operation of this product, appropriate thermostat mounting clips are required but may not be included. The buyer should have compatible clips available prior to installation. Recommended clips include Supco part numbers SL243, SL245, or SL249 (or equivalent). Failure to use proper mounting hardware may result in improper performance or damage.