Weil-McLain®, 633-500-020, Thermostat Repair Kit

Weil-McLain 633-500-020 Thermostat Repair Kit for AquaPLUS Indirect Water Heaters

The Weil-McLain 633-500-020 Thermostat Repair Kit is a manufacturer-approved replacement component designed for use with Weil-McLain AquaPLUS indirect-fired water heater models 35, 45, 55, and 85. This kit restores temperature control functionality in systems where the original thermostat has failed or degraded.

As an OEM part, it is built to meet original equipment specifications for reliable operation and compatibility. The kit includes a direct replacement thermostat and installation documentation for proper service integration.

Compatible Models

• AquaPLUS 35
• AquaPLUS 45
• AquaPLUS 55
• AquaPLUS 85

Product Details

• OEM Part Number: 633-500-020
• Component: Replacement thermostat
• Use Case: Service and repair of temperature regulation function
• Construction: Durable materials rated for domestic hot water systems

Installation Requirements

This replacement kit is intended for field installation by qualified personnel. While the procedure is relatively straightforward for those experienced with indirect water heaters, care must be taken to ensure proper sensor placement and electrical connections. Follow all manufacturer service procedures and observe applicable local plumbing and electrical codes.

Contractor Notes

This kit provides a direct-fit solution for common thermostat failure in AquaPLUS models. It is useful for both scheduled service work and field replacements during diagnostics. Always verify compatibility by model number before installation.

Included in the Kit

• Replacement thermostat unit
• Installation instructions