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OEM Carrier Control Transformer 40VA 208/240V-24V — PY4GNAA24040AA
Carrier

OEM Carrier Control Transformer 40VA 208/240V-24V — PY4GNAA24040AA

SKU: CARRIE-PY4GNAA24040AA-TRANSFORMER-HT01BD209 Brand: Carrier
✓ Guaranteed to fit PY4GNAA24040AA — or your money back. Terms

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Texas CMBL #19328542014
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OEM Carrier Control Transformer 40VA 208/240V to 24V for Model PY4GNAA24040AA

This is the genuine OEM Carrier control transformer (part #HT01BD209) factory-specified for the Carrier PY4GNAA24040AA packaged unit. The transformer steps down 208/240V line voltage to the 24V control circuit voltage that powers your thermostat, contactor coil, and every low-voltage component in the system. When this part fails, the result is total loss of control — the thermostat goes dark, the system won't respond to any call for heating or cooling, and the unit sits completely dead despite having full line voltage present. A failed transformer is one of the first things an experienced tech checks in a no-response scenario.

  • Specs: 208/240V Primary | 24V Secondary | 40VA Rating | 50/60 Hz | OEM Part # HT01BD209 | Replaces HT01BD207, HT01CN232, 9076-00
  • OEM vs Generic: This factory OEM unit is wound to exact Carrier tolerances, ensuring the full 40VA capacity needed to reliably pull in contactors and hold the control circuit stable under load. Generic transformers often run under-rated VA, causing nuisance tripping and premature burnout.
  • Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Label all low-voltage wires (R, C, G, Y, W) before disconnecting. Verify 24V output on secondary terminals with a multimeter before closing the unit up.
  • Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Direct OEM replacement for Carrier model PY4GNAA24040AA packaged units. Also compatible with Bryant and Payne units sharing the HT01BD209 / HT01BD207 / HT01CN232 transformer specification. Always confirm your unit's control voltage requirement (24V) and VA demand against this transformer's 40VA rating before ordering. Questions about fitment? Our HVAC parts specialists verify compatibility before you order — contact us today and get your system back online fast.

Shipping Information

  • Orders placed before 3PM CST ship same business day
  • Standard delivery: 2-5 business days
  • Express shipping available at checkout
  • Free shipping on orders over $99
  • Tracking number emailed upon shipment

Return Policy

  • 30-day returns on unused parts in original packaging
  • Electrical parts (capacitors, contactors, control boards) are final sale once installed
  • Email info@nationalhvacparts.com to initiate a return
  • Refunds processed within 5-7 business days

Frequently Asked Questions

Does this Transformer fit my Carrier OEM Carrier Control Transformer 40VA 208/240V-24V — PY4GNAA24040AA?
Yes. This is the factory-specified OEM transformer for the Carrier OEM Carrier Control Transformer 40VA 208/240V-24V — PY4GNAA24040AA. It is a direct drop-in replacement that fits without modification. Always verify the model number on your equipment nameplate before ordering.
How do I replace the transformer on my Carrier OEM Carrier Control Transformer 40VA 208/240V-24V — PY4GNAA24040AA?
Difficulty: Medium (30–45 min)
Step 1: Turn off breaker. Step 2: Photo wiring connections. Step 3: Disconnect wires from old transformer. Step 4: Remove mounting hardware. Step 5: Install new transformer, reconnect wires matching voltage ratings. Step 6: Verify 24V output with multimeter.
My thermostat has no power. What failed?
Thermostat with no display = failed 24V transformer (or blown control board fuse). Check the 3A/5A fuse on the control board first ($1–$5 fix). If fuse is good but no 24V output from transformer, replace transformer.
Is this transformer compatible with Bryant or Payne too?
Many Carrier parts are cross-compatible with Bryant and Payne since all three brands are manufactured by Carrier Global Corporation. The same physical part is often used across brand labels with different model numbers. To verify: check your Bryant or Payne equipment service manual for cross-compatible part numbers, or email info@nationalhvacparts.com with your model number.
Should I use OEM or aftermarket for my Carrier transformer?
OEM recommended for reliability and warranty compatibility. OEM parts match exact factory specifications for proper fit, performance, and safety. While aftermarket alternatives cost less upfront, the risk of improper fit and reduced lifespan usually makes OEM the better value long-term.
How fast does National HVAC Parts ship?
Orders placed before 3:00 PM CST ship the same business day. Standard delivery is 2–5 business days anywhere in the continental United States. Express shipping available at checkout. We ship from Houston, TX to all 50 states. 30-day return policy on all parts.
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Mike Rivera
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