Cleveland Controls DDP 106 380 Sensing Switch 320734 701 HVAC technicians should prioritize this HVAC technicians should prioritize this factory authorized part to ensure the internal diaphragm and electrical contacts meet the rigorous demands of residential furnace diagnostic circuits and safety protocols the system gauge scales can be adjusted if the safety relief valve is matched to the specific requirements of the downstream pneumatic equipment Robust Construction: Engineered to withstand harsh environments with a wide operating temperature range of 40°F to 176°F connect the sample line to the "L" (low) inlet while leaving the "H" (high) inlet open to the atmosphere