Resideo L4006A1678 Aquastat Controller R-22 Field technicians should note that

Field technicians should note that the MK-4611 is functionally identical to the MK-4611-0-0-2

the HSI (Hot Surface Ignitor) may be cracked or failing

normally open switch is engineered to detect specific vacuum thresholds

Maximized Performance: Prevents nuisance tripping while providing a robust defense against electrical surges and thermal overloads

This occurs when the control board fails to receive a microamp signal from the flame rod

Resideo L4006A1678 Aquastat Controller R-22 Field technicians should note thatThe Resideo L4006A1678 Aquastat Controller is a professional grade immersion sensing device engineered for high limit or low limit temperature control in hydronic heating systems. This immersion controller features SPST contacts designed to break on temperature rise, making it a critical component for regulating boiler water temperatures or protecting storage tanks from overheating. Equipped with a 3 8" x 2 7 8" copper bulb and a 3 inch capillary, the