Refer to the System 450 Series Modular Control Systems with Standard Control Modules Technical Bulletin (LIT-12011459), the System 450 Series Modular Controls Product Bulletin (LIT-12011458), and the installation instructions for product specifications, detailed installation procedures, and important product safety information.
In this solar heating example, a solar panel circulating pump is controlled by differential temperature (diFT). When the temperature of the solar panel is 10F° above the temperature of the water in the storage tank, the solar panel circulating pump begins to run.
When the differential temperature (dON1) is met, the normally open contacts of relay output 1 close, energizing C2 and starting the circulating pump. The pump cycles off when the differential temperature (dOFF1) falls to 5F°. The room temperature circulating pump is controlled by the room temperature sensor (Sn-3) and the storage tank sensor (Sn-2).
When heating is required, the normally open contact on RelayOutput 2 (OUTR2) closes, energizing C1 and starting the room temperature circulating pump. Relay Output 3 (OUTR3) locks out the room temperature circulating pump if the water in the tank drops below 70°F, allowing the pump to restart when the water temperature rises to 75°F or higher.