The unit features white color coding for quick field identification and operates with a strict tolerance of +7 degrees F / -8 degrees F

which lead to terminal heat exchanger corrosion or pressure switch lockout

The Air Over motor housing is designed to be cooled by the fan's own airflow

Operating on a 0(2) to 10 VDC or 0(4) to 20 mA proportional control signal

Tjernlund Products PS1503 Switch 322027-701 The unit features white colorThe Tjernlund Products PS1503 is a high sensitivity duct pressure switch engineered to automate HVAC accessories by detecting positive air pressure within the supply plenum or trunk lines. As the direct replacement for DFS 221 227, this SPST normally open switch simplifies field installations by eliminating the need for complex interlock wiring with the furnace blower. The PS1503 duct airstat features a snap acting mechanism triggered by a precise