Differential Thermostat KIT

A differential thermostat  is actually the same thing as a differential controller if it's used to control something like a pump or a fan. This differential thermostat is normally used to regulate a pump and maximize the heat harvest from a solar collector. Soooooo what makes the Differential Controller Kit so special besides, low cost, durability, versatility and ease of construction. Although small this differential thermostat has a relay designed to regulate AC or DC pumps, but there are two other feature that makes this thermostat special... SAFETY & STABILITY.  

SAFETY...The 5 Volt regulator, built into the circuit supplies power to the probes. If the probe wires are ever shorted out the current supplied by the voltage regulator is limited, so you will never have to worry about a melt down because of an accidental short.

STABILITY.. The 5 Volt regulator supplies the temperature sensors with a stable voltage reference. If  12 Volt PV power supply is used to power a DC pump the feedback voltage to the controller drops as the sunlight intensity drops. This feature allows the relay to turn off sooner than normal and increase the life expectancy of a back up battery in a PV system by preventing an unnecessary power drain leading to a dead battery.
A 9 Volt DC wall transformer is is used to supply power to the controller when the controller is used to regulate a AC pump. If for some reason the wall transformer is damaged so that the DC supply voltage drops the pump will shut down sooner than normal. This is both a SAFETY & STABILITY feature of this basic differential thermostat.

To power an AC pump you will need a 9VDC Wall transformer (actual voltage 12Volts to 14Volts) Features of the basic Differential Thermostat