OEM Carrier Control Transformer 40VA for Model C48A503061

This OEM Carrier control transformer (part# HT01BD236) is the factory-specified replacement for the Carrier C48A503061 packaged unit. The transformer steps down 120V line voltage to 24V AC to power the entire control circuit — including the thermostat, contactor coil, gas valve, and control board. When the transformer fails, nothing in the system responds: the thermostat goes blank, the unit won't energize, and there is zero 24V signal at any control terminal. If you've already confirmed your thermostat and fuses are good, a failed transformer is the next most likely culprit.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | Foot-mount bracket | Factory-matched OEM tolerances for stable, consistent 24V output
• OEM vs Generic: OEM transformers from Carrier are wound to exact VA and voltage tolerances, ensuring your control board and gas valve receive clean, stable 24V power. Off-brand transformers can sag under load, causing nuisance lockouts, erratic thermostat behavior, and premature contactor coil failure.
• Install difficulty: 2/5 — Disconnect all power before servicing. Tools needed: flathead and Phillips screwdriver, multimeter (to confirm 0V before touching terminals and 24V output after install), wire nuts or spade connectors. Always label or photograph wiring before disconnecting. Verify fuse or circuit breaker is intact before condemning the transformer.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier C48A503061 packaged unit. Verify your existing transformer's VA rating and primary/secondary voltages on the unit's data plate or wiring diagram before ordering. If you have any questions about fitment, our HVAC parts specialists are available to confirm compatibility before you buy — no guesswork required.