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OEM Carrier Control Transformer 40VA 208/240V–24V for PY3PNA042090AA
Carrier

OEM Carrier Control Transformer 40VA 208/240V–24V for PY3PNA042090AA

SKU: CARRIE-PY3PNA042090AA-TRANSFORMER-HT01BD209 Brand: Carrier
✓ Guaranteed to fit PY3PNA042090AA — 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 PY3PNA042090AA

This is the genuine OEM control transformer (part number HT01BD209) factory-specified for the Carrier PY3PNA042090AA. The transformer steps down 208/240V line voltage to a stable 24V signal that powers your thermostat, control board, gas valve, and all low-voltage safety circuits. When this transformer fails, the entire control circuit goes dark — the thermostat becomes unresponsive, the system won't call for heating or cooling, and no safety safeties can operate. A failed transformer is one of the most common reasons a system appears completely dead despite having power at the disconnect.

  • Specs: 208/240V Primary | 24V Secondary | 40VA rated | 50/60Hz | Class 2 control transformer | Direct OEM replacement for HT01BD207, HT01CN232, and 9076-00
  • OEM vs Generic: This OEM unit is wound to exact Carrier factory tolerances, ensuring steady 24V output under full VA load. Generic transformers can sag under load, causing nuisance lockouts, erratic thermostat behavior, or premature control board failure.
  • Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, wire strippers, multimeter. Label all low-voltage wiring before disconnecting. Confirm 24V output with a multimeter after installation before restoring system operation.
  • Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Engineered as the factory-matched replacement for Carrier model PY3PNA042090AA. Also replaces obsolete Carrier part numbers HT01BD207, HT01CN232, and 9076-00. Verify your unit's model and serial number before ordering, or contact our team for fitment confirmation before you buy.

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 PY3PNA042090AA?
Yes. This is the factory-specified OEM transformer for the Carrier PY3PNA042090AA. 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 PY3PNA042090AA?
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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