York S1-THEH21NS Thermostat 321894-706 Safety Interlock: Crucial for preventing

Safety Interlock: Crucial for preventing ignition if the vent pipe or heat exchanger is obstructed

Using it in a Natural Gas system will cause improper combustion due to the different pressure and flow requirements of liquid propane

Durable Construction: Features a NEMA 1 protection rating and an appliance cable for secure electrical termination

maintaining strict compliance in residential and commercial furnaces

York S1-THEH21NS Thermostat 321894-706 Safety Interlock: Crucial for preventingUpgrading or replacing a residential control interface requires a reliable, no nonsense solution like the York S1 THEH21NS Thermostat. This Source 1 OEM thermostat is a non programmable heat pump thermostat engineered for single stage cooling and two stage heating (2H 1C thermostat) applications. Designed to meet strict original equipment specifications, it ensures precise temperature regulation without the complexity of modern scheduling interfaces,