Resideo TH140-28-01-B Programmable Thermostat 320788-704 the Aprilaire 5531 Valve may

the Aprilaire 5531 Valve may be obstructed by scale or sediment

Industrial-Grade Reliability: Built with high-quality relay contacts to handle the inductive loads of unit heater fan motors in demanding environments

maintaining safety and performance standards essential for professional contractors

the internal safety interlock switch is paramount

you know that keeping a system clean and dry is the baseline for preventing mid-summer callbacks

Resideo TH140-28-01-B Programmable Thermostat 320788-704 the Aprilaire 5531 Valve mayThe Resideo TH140 28 01 B Programmable Thermostat is a versatile 7 day programmable digital thermostat designed for high precision control in hydronic, line voltage, and low voltage heating environments. Engineered to handle everything from millivolt systems to 240 Vac heating applications, this unit is a staple for technicians installing electric baseboard heaters, as well as gas or oil fired boilers. With a single pole double throw (SPDT) switching