Resideo AT72D1089 Transformer R-448A if it fails to close

if it fails to close at 1

ensuring a drop-in fit with no cabinet modifications required

intermittent pressure switch trips

Its design incorporates a top-guided stem and a PTFE-faced elastomer soft seat

When swapping out an old L4008E1305 equivalent or servicing a Teledyne Laars unit

Resideo AT72D1089 Transformer R-448A if it fails to closeThe Resideo AT72D1089 Transformer is a professional grade solution for technicians requiring a reliable 120V to 24V step down for HVAC control circuits. Engineered with a 40VA power rating, this unit is built to manage the electrical load of 24VAC thermostats, gas valves, and multi zone relays. The hardware features a 4"x4" plate mount design and a NEMA Type D enclosure, ensuring compliance with NEC Class 2 (not wet) and Class 3 (wet) requirements.