OEM Carrier Control Transformer 40VA 208/240V to 24V for Model PY3GNAA42090NA

This OEM control transformer (part #HT01BD209) is the factory-specified replacement for the Carrier PY3GNAA42090NA packaged gas/electric unit. The transformer steps down 208/240V line voltage to the 24V signal used by your thermostat, control board, gas valve, and every other low-voltage component in the system. When it fails, the entire control circuit goes dead — the thermostat goes blank, the system will not respond to any call for heat or cooling, and you may measure zero voltage on the 24V secondary terminals.

• Specs: 40VA rated | 208/240V primary input | 24V secondary output | 50/60 Hz | Replaces HT01BD207, HT01CN232, and 9076-00
• OEM vs Generic: This is a genuine Carrier OEM transformer wound to exact VA and voltage tolerances. Undersized or off-spec generic transformers can overheat, trip their internal breaker repeatedly, or damage downstream control boards — making OEM the only safe choice here.
• Install difficulty: 2/5 — Shut off power at the disconnect and breaker before starting. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or terminal connectors. Always verify 0V at the primary leads before touching any wiring. Label wires before removal.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Direct OEM replacement for Carrier model PY3GNAA42090NA packaged units. Cross-references HT01BD207, HT01CN232, and 9076-00. Always verify primary voltage on your unit's data plate before ordering — 460V primary units require a different part number. Questions? Our HVAC parts specialists verify fitment before you order — no guesswork.