Weil McLain 633-900-130 Residential Thermostat

When you're servicing or installing Weil-McLain Plus or Gold Plus series indirect-fired water heaters, maintaining thermal accuracy is non-negotiable for system longevity and prevents short-cycling. The Weil-McLain 633-900-130 Residential Thermostat kit is an essential OEM replacement part designed for a precise operating range of 90°F to 160°F. This aquastat control integrates directly with factory-configured drywells, ensuring the sensor bulb makes full contact for reliable domestic hot water regulation. As a technician, you know that using anything other than an HVAC part with the correct temperature differential can lead to stacking or nuisance calls; this kit includes the dial knob, mounting screws, and instructions needed for a clean swap on 30-80 gallon tanks.

• Application Specific: Engineered specifically for compatibility with Weil-McLain Plus (30-60) and Gold Plus (30-80) models.
• Reliable Temperature Control: Wide 90°F to 160°F range allows for high-efficiency settings while meeting safety requirements for Legionella prevention.
• Complete Replacement Kit: Includes the thermostat unit, calibrated adjustment knob, and necessary hardware to minimize time on the job site.
• OEM Standards: Restores factory-spec performance and cycling behavior to the indirect water heater.

• Does this kit require draining the tank for installation? No. The sensing bulb inserts into a drywell; you only need to ensure the bulb is fully seated to avoid delayed heat calls.
• Will this work on the 100-120 gallon Gold Plus tanks? This specific part (633-900-130) is calibrated for the 30-80 gallon series; larger tanks usually require a different part number (635-100-010).
• What if the burner doesn't cut out at the setpoint? Verify that the control knob is properly seated on the thermostat shaft and that there are no obstructions in the drywell preventing accurate sensing.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.