OEM Carrier Control Transformer 120V–24V 40VA for Model PH3ZNA036000AA

This is the OEM factory-specified control transformer (part number HT01BD242) for the Carrier PH3ZNA036000AA packaged heating unit. The control transformer steps down line voltage (120V primary) to 24V AC for the low-voltage control circuit — powering the thermostat, contactor coil, gas valve, and all safety switches. When the transformer fails, nothing in the control system responds: the thermostat goes dark, the system won't call for heat or cooling, and the contactor won't energize. It is one of the first components to check when a unit goes completely dead despite normal line voltage at the disconnect.

• Specs: 120V primary | 24V secondary | 40VA rated | OEM part number HT01BD242 | Factory-matched for Carrier packaged unit control circuits
• OEM vs Generic: This is the exact OEM unit sourced from Carrier. OEM transformers are wound and insulated to factory specifications, ensuring correct VA output and long-term thermal stability under continuous cycling — generic units often run underrated VA, causing premature thermal cutout trips.
• Install difficulty: 2/5 — Turn off all power at the disconnect and breaker before starting. Tools needed: flathead and Phillips screwdrivers, multimeter (verify 24V output after install), wire nuts or push-in connectors. Label or photograph all low-voltage wiring before disconnecting the old transformer.
• Warranty: 1-year OEM factory warranty against defects. In-stock units ship same business day from our warehouse when ordered before 3PM local time.

Compatibility: Engineered as a direct OEM replacement for the Carrier PH3ZNA036000AA 3-ton packaged heating unit. Always verify your unit's data plate confirms 120V/24V transformer specifications before ordering. Not sure if this is the right part? Our HVAC parts specialists verify fitment at no charge — reach out before you order.