What causes a 2-wire thermopile to fail prematurely

the 6208EMQ is shipped with a light rust-preventative coating

or if the pilot lights but the main burner fails to kick in

Direct Integration: Features standard spade terminals for quick connection to the furnace control board and simplified installation in tight burner compartments

MAMAC Systems HU-225-2-MA Humidity Transducer Els PW 17895 What causes a 2-wire thermopileThe MAMAC Systems HU 225 2 MA is a high performance wall humidity transducer engineered for precise monitoring in demanding HVAC and Building Automation Systems (BAS). Featuring a cross linked bulk polymer capacitive sensing element, this unit delivers a reliable 4 20mA 2 wire output with 2% RH accuracy across the full 0 100% range. Built to withstand challenging environments, the sensing element is shielded by a proprietary hydrophobic ePTFE filter,