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OEM Carrier Transformer 40VA 120V/24V for PY3PNA042090NB
Carrier

OEM Carrier Transformer 40VA 120V/24V for PY3PNA042090NB

SKU: CARRIE-PY3PNA042090NB-TRANSFORMER-HT01BD209 Brand: Carrier
✓ Guaranteed to fit PY3PNA042090NB — or your money back. Terms

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Texas CMBL #19328542014
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OEM Carrier Control Transformer 40VA 120V/24V for Model PY3PNA042090NB

This is the genuine OEM replacement transformer for the Carrier PY3PNA042090NB packaged unit. The transformer is the heartbeat of your system's low-voltage control circuit — it steps down 120V line voltage to the 24V signal voltage required by your thermostat, contactor coil, gas valve, and control board. When it fails, nothing works: no call for heat or cool reaches any component, and the system goes completely unresponsive. A blown fuse on the secondary winding or a shorted coil are the most common failure modes.

  • Specs: 40VA rated | Primary: 120V AC | Secondary: 24V AC | OEM Part Number: HT01BD209 | Factory-matched for Carrier PY3PNA042090NB packaged units
  • OEM vs Generic: OEM transformers are wound and insulated to Carrier's exact VA and voltage tolerance specs. Undersized or off-tolerance generic units can fail under high-demand conditions, repeatedly blowing the 3A control fuse and masking the root cause of the problem.
  • Install Difficulty: 2/5 — Shut off all power at the disconnect before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Always test secondary voltage output (should read 24–28V AC) after installation before restoring thermostat wiring. Photograph all wiring before disconnecting.
  • Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PY3PNA042090NB packaged unit (4-ton, 90,000 BTU gas/electric combination). Verify your existing transformer's VA rating and primary/secondary voltages on the unit's data plate before ordering. Our technical team is available to confirm fitment — contact us before you order if you have any questions.

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 PY3PNA042090NB?
Yes. This is the factory-specified OEM transformer for the Carrier PY3PNA042090NB. 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 PY3PNA042090NB?
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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