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OEM Carrier Control Transformer 40VA 208/240V–24V — PY3GNAA30040NA
Carrier

OEM Carrier Control Transformer 40VA 208/240V–24V — PY3GNAA30040NA

SKU: CARRIE-PY3GNAA30040NA-TRANSFORMER-HT01BD209 Brand: Carrier
✓ Guaranteed to fit PY3GNAA30040NA — 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 PY3GNAA30040NA

This OEM control transformer (part number HT01BD209) is the factory-specified replacement for the Carrier PY3GNAA30040NA system. The transformer steps down line voltage from 208/240V to the 24V signal required by your thermostat, control board, contactor coil, and all low-voltage safety circuits. When this component fails, the entire 24V control circuit goes dark — the thermostat becomes unresponsive, the system will not energize, and no call for heating or cooling is answered. It is one of the first components an experienced technician checks when a unit shows zero response to any thermostat command.

  • Specs: 40VA capacity | 208/240V primary input | 24V secondary output | 50/60 Hz | Class 2 control transformer | Factory-matched Carrier OEM specification
  • OEM vs Generic: This is a genuine Carrier OEM part built to exact factory tolerances. Generic transformers may carry higher VA ripple and looser voltage output tolerances, which can stress sensitive control boards and solid-state components over time. OEM is the only safe choice for critical 24V control circuits.
  • Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before touching any wiring. Tools needed: flat-head and Phillips screwdrivers, wire stripper, multimeter. Label or photograph all low-voltage wiring before disconnecting. Confirm output voltage with a multimeter after installation before restoring full power.
  • Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PY3GNAA30040NA. Also replaces legacy part numbers HT01BD207, HT01CN232, and 9076-00. Always verify your unit's data plate voltage specifications match the 208/240V primary rating before ordering. Our team is available to confirm fitment — just reach out before you buy. Order today and receive same-day shipping on all in-stock parts.

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 — PY3GNAA30040NA?
Yes. This is the factory-specified OEM transformer for the Carrier OEM Carrier Control Transformer 40VA 208/240V–24V — PY3GNAA30040NA. 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 — PY3GNAA30040NA?
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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