If a furnace or air handler fails to initiate the startup sequence even with the thermostat calling for heat

ensuring long-term reliability in commercial and industrial heating applications

Whether troubleshooting a boiler that won't fire due to an open safety circuit or performing a scheduled draft test

and NSF P1 certified

Robertshaw 620-406 Transformer If a furnace or airThe Robertshaw 620 406 is a heavy duty 208 240V to 24V HVAC transformer engineered for reliable step down power in demanding light commercial and residential control circuits. Rated at 40VA, this open frame transformer provides the stable secondary voltage output required to drive contactors, relays, and circuit boards without voltage sag. The foot mount design ensures a secure installation within furnace cabinets or air handler control boxes, making