The scale is built from high-impact polystyrene

providing an essential safety interlock that prevents the main gas valve from opening during ignition failure scenarios

this Source 1 part is physically indexed for York and Coleman units

a sudden drop in hot water volume

used extensively in 155

Dwyer Instruments 2015 Pressure Gage 320735-701 The scale is built fromThe Dwyer Magnehelic 2015 is the industry standard for measuring differential pressure in HVAC systems and cleanroom environments. Designed for 0 15. 0" w. c. ranges, this gage utilizes a frictionless Magnehelic movement that eliminates wear and hysteresis, ensuring consistent accuracy within 2% of full scale. The 4" diameter dial face provides clear visibility for monitoring air or non combustible gases, while the die cast aluminum housing handles