The Marley Engineered Products 4520-0011-000 Limit Switch is a high-precision 300F CU AUTO limit switch engineered for critical thermal protection in industrial and commercial heating applications

this spring ensures consistent hysteresis performance and prevents valve sticking in critical HVAC pneumatic systems

What causes a furnace limit switch to trip repeatedly

000 to 290

Durable Polymer Construction: High-grade polyethylene pneumatic tubing resists moisture

UCS-621E Control Module 30067439-890 The Marley Engineered Products 4520-0011-000Upgrade your systems response profile with the UCS 621E Sequencer Control Module, a solid state powerhouse designed for high precision multistage HVAC control. This veteran grade six stage sequencer functions as a direct replacement for the legacy UCS 621, offering seamless integration into existing building automation systems (BAS). Built to handle a dual 24 VAC VDC supply voltage, the module accepts a wide range 0 20 mA or 0 15 VDC input signal,