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OEM Carrier Control Transformer 40VA 208/240V-24V — PY4GPAA48090AA
Carrier

OEM Carrier Control Transformer 40VA 208/240V-24V — PY4GPAA48090AA

SKU: CARRIE-PY4GPAA48090AA-TRANSFORMER-HT01BD209 Brand: Carrier
✓ Guaranteed to fit PY4GPAA48090AA — or your money back. Terms

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Texas CMBL #19328542014
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Govt POs Accepted

OEM Carrier Control Transformer 40VA 208/240V to 24V for Model PY4GPAA48090AA

This is the genuine OEM control transformer (part #HT01BD209) factory-specified for the Carrier PY4GPAA48090AA packaged HVAC 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 result is total loss of control circuit power — nothing responds, the thermostat goes blank, and the unit will not start. A failed transformer is often misdiagnosed as a bad board, making correct identification critical before replacing more expensive components.

  • Specs: 40VA capacity | 208/240V primary input | 24V secondary output | 50/60Hz | OEM part number HT01BD209 | Also cross-references HT01BD207, HT01CN232, and 9076-00
  • OEM vs Generic: OEM transformers are wound to exact factory VA tolerances, protecting sensitive control boards from voltage fluctuation. Generic units often run under-spec VA ratings, causing nuisance trips and premature board failure under full system load.
  • Install difficulty: 2/5 — Shut off all power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, wire stripper. Always verify 24V output with a meter before reconnecting controls. Photograph existing wiring before disconnecting.
  • Warranty: 1-year OEM factory warranty against defects. Ships same business day from our warehouse.

Compatibility: Factory-matched for Carrier model PY4GPAA48090AA packaged HVAC unit. Also compatible with select Bryant and Payne models using the same 40VA, 208/240V-to-24V transformer specification — verify your unit's data plate and wiring diagram before ordering. Have questions? Our fitment team confirms compatibility 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 OEM Carrier Control Transformer 40VA 208/240V-24V — PY4GPAA48090AA?
Yes. This is the factory-specified OEM transformer for the Carrier OEM Carrier Control Transformer 40VA 208/240V-24V — PY4GPAA48090AA. 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 — PY4GPAA48090AA?
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
HVAC Parts Specialist — Online