Xylem 343200 Replacement Bellows Assembly Low Water Cutoff

Product Description

The XYLEM 343200 is a replacement bellows assembly designed for use in low water cutoff controls on steam boiler systems. The bellows element responds to pressure changes inside the control body, actuating the electrical switch contacts that monitor and maintain safe boiler water levels. When water drops below the safe threshold, the bellows triggers the cutoff switch, stopping burner operation and preventing dry firing. Licensed HVAC technicians and boiler service professionals install this assembly as a direct replacement when the original bellows shows signs of fatigue, leakage, or failure to actuate reliably. At 1.37 pounds, it is a compact, service-ready component.

This bellows assembly is suited for residential and commercial steam heating systems that use McDonnell Miller low water cutoff controls. It is a factory-specified replacement for the SA63-5 bellows assembly within the control housing. Proper function of this component is critical to boiler safety, as it directly governs the dry-fire protection response. It is intended for service calls and planned maintenance where the control body remains in place and only the internal bellows assembly requires replacement.

Key Features

• Direct replacement for the SA63-5 bellows assembly in McDonnell Miller low water cutoff controls
• Actuates electrical switch contacts in response to pressure changes inside the control
• Prevents dry firing by triggering burner shutoff when water level drops below safe threshold
• Suitable for both residential and commercial steam boiler applications
• Lightweight at 1.37 pounds for straightforward handling during service

Compatibility

Designed as a direct OEM-style replacement for the SA63-5 bellows assembly used in McDonnell Miller low water cutoff controls on steam boiler systems. No additional compatible model numbers were specified in the available product data.

Installation Notes

Installation should be performed by a licensed HVAC technician or qualified boiler service professional. Before servicing the low water cutoff control, shut down the boiler, isolate electrical power to the control circuit, and allow the system to cool and depressurize fully. Follow all applicable local codes and the control manufacturer's service instructions when disassembling the control body and seating the replacement bellows assembly. Do not restore power or refire the boiler until the control has been reassembled, leak-checked, and verified for proper operation.

Technical Specifications

• Weight: 1.37 pounds
• Replaces: SA63-5 Bellows Assembly

Standard Information

• Brand: XYLEM
• Manufacturer Part Number: 343200