This is often caused by a cracked heat exchanger

whereas the "NSA" version utilizes a standard terminal block for field-wired connections

the top actuator assembly can be rotated in 90-degree increments to accommodate specific piping layouts and clearance requirements in tight mechanical spaces

the burner circuit will re-energize automatically

this is a complete ECM 5

Resideo L6006A1244 Aquastat Controller 321702-401 This is often caused byThe Resideo L6006A1244 Aquastat Controller is a high performance immersion temperature controller engineered for precise regulation of liquids in boilers and storage tanks. Featuring SPDT switching action, this versatile unit functions as a high limit, low limit, or circulator control, ensuring reliable system operation under varying thermal loads. The controller utilizes a 3 8" x 2 7 8" copper bulb connected via a 3" capillary for accurate sensing.