Lennox 10Y66 Transformer The Johnson Controls T-4000-2138 is

The Johnson Controls T-4000-2138 is a professional-grade beige plastic thermostat cover designed specifically for T-4000 series pneumatic room thermostats

Standard T-4002-124 mounting brackets are typically already in place on the wall

or develops a leak

providing a consistent arc for reliable gas ignition in various cabinet configurations

Technicians can rely on this ICP furnace safety switch for a secure fit in 80% and 90% AFUE gas furnaces where temperature regulation is critical

Lennox 10Y66 Transformer The Johnson Controls T-4000-2138 isThe Lennox 10Y66 Transformer Power Choke is a critical OEM HVAC replacement part engineered for high performance voltage stabilization and EMI suppression. As a veteran technician knows, managing electrical noise from compressor and fan motors is essential to protecting the integrated furnace control board. This power choke transformer acts as a passive filter, eliminating high frequency interference and mitigating voltage spikes that can trace back