OEM Carrier 24V Control Transformer 40VA for Model PH3PNA024000AA

This OEM control transformer (part #HT01BD242) is the factory-specified replacement for the Carrier PH3PNA024000AA system. The transformer steps down line voltage (120V) to the 24V AC signal that powers your thermostat, control board, and all low-voltage safety and switching circuits. When this part fails, the entire control circuit goes dark — the thermostat becomes unresponsive, the system won't call for heating or cooling, and nothing works despite power being present at the unit.

• Specs: Primary voltage: 120V AC | Secondary voltage: 24V AC | VA rating: 40VA | Factory OEM part number: HT01BD242 | Direct plug-and-play fit for Carrier PH3PNA024000AA
• OEM vs Generic: This is a genuine OEM Carrier transformer wound to exact factory VA and voltage tolerances. Generic transformers often fall short of rated VA output under load, causing nuisance tripping of downstream controls and shortened component life.
• Install difficulty: 2/5 — Shut off all power to the unit at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdriver, multimeter (to confirm 24V output after install), wire nuts or spade terminals. Always photograph the original wiring connections before removal.
• Warranty: 1-year OEM factory warranty against defects. Orders placed by 3PM local time ship same business day from our stocked warehouse.

Compatibility: Designed and factory-matched for Carrier model PH3PNA024000AA. Confirm your unit's control circuit voltage and VA rating on the system data plate before ordering. Not sure it fits? Our HVAC parts specialists verify fitment at no charge — contact us before you buy.