30 Gal. Burner for Bock BK-3 Series Water Heaters

Rheem SP310020 Lower Thermostat – OEM Component for Electric Water Heaters

The Rheem SP310020 is an OEM lower thermostat designed for electric residential water heaters utilizing dual heating elements. This snap-in thermostat provides precise temperature regulation for the lower element, supporting efficient hot water recovery and balanced tank performance.

Built to meet Rheem’s exact engineering standards, the SP310020 includes an integral manual reset ECO (Energy Cut-Off) switch and is calibrated for residential service applications. It is compatible with a range of Rheem models and is used as the lower control in systems requiring independent upper and lower thermostat operation.

Component Highlights

• Thermostat Type: Single-pole, single-throw (SPST) with integrated ECO
• Mounting: Snap-in bracket for 1/2” tank well with standard terminal spacing
• Temperature Adjustment Range: 90°F – 150°F
• Manual Reset High Limit: Factory set at 170°F (±5°F)
• Construction: Durable bimetallic sensor design rated for residential demand

Technical Specifications

• Part Number: SP310020
• Voltage Rating: 240V AC nominal
• Amperage: 20A resistive load
• Function: Controls lower element in dual-element electric tank configurations
• Compatibility: Rheem electric water heaters with dual thermostats
• Certifications: UL Listed and CSA Approved

Installation Notes

Replacement requires full power isolation and verification of proper terminal torque. Element continuity, tank grounding, and wire insulation integrity should be checked during service. Use with properly matched heating elements. All field wiring must meet NEC standards and any applicable local code requirements.

This thermostat is not field-adjustable beyond the specified temperature dial and should not be used in non-compatible units or modified configurations. A qualified service technician should perform installation to ensure optimal safety and equipment function.

Field Application & Service Guidance

Contractor Use: Stocked as a standard replacement for lower thermostats in Rheem dual-element electric water heaters. Suited for service calls involving lower tank temperature fluctuations, failed cycling, or ECO trips due to excessive tank temperatures. Built-in ECO provides a safety cutoff in overheat conditions.

Servicing Notes: Always inspect insulation backing and mounting clip before reinstallation. Confirm that thermostat has firm surface contact with tank well and that wiring is free from arcing or corrosion. Reset ECO only after temperature issues are resolved and source conditions corrected.

Performance Summary

• Precision Control: Maintains target water temperature in the lower section of the tank
• Safety Protection: Integrated ECO for thermal overload shutdown
• Rheem OEM: Matches original equipment specifications—no modifications needed
• Service-Friendly: Fast replacement using existing bracket and terminal layout