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OEM Carrier 40VA 120V to 24V Control Transformer for C48A203564 | National HVAC Parts
Carrier

OEM Carrier 40VA 120V to 24V Control Transformer for C48A203564 | National HVAC Parts

SKU: CARRIE-C48A203564-TRANSFORMER-HT01BD702 Brand: Carrier

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Texas CMBL #19328542014
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OEM Carrier Control Transformer 40VA for Model C48A203564

This OEM replacement transformer (part number HT01BD702) is the factory-specified control circuit transformer for the Carrier C48A203564 packaged unit. The transformer steps down 120V line voltage to the 24V signal voltage required to power the thermostat, control board, contactor coil, and all low-voltage control components. When this transformer fails, the entire control circuit goes dead — the thermostat goes blank, the system won't respond to any calls for heating or cooling, and no contactors or relays will energize. It is often the first component to check when a unit appears completely unresponsive despite confirmed line voltage at the unit.

  • Specs: 40VA rating | Primary: 120V | Secondary: 24V | OEM part number HT01BD702 | Factory-matched for Carrier C48A203564 packaged systems
  • OEM vs Generic: OEM transformers are wound and rated to exact factory VA specifications. Undersized or off-tolerance generic units can overheat, trip thermal protection, or fail prematurely under full control-circuit load — especially in multi-stage or heat pump applications.
  • Install difficulty: 2/5 — Disconnect all power before servicing. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Confirm 24V output on secondary before reassembling control panel. Always verify wiring diagram on unit door.
  • Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier C48A203564 packaged unit. Verify primary voltage (120V) and VA rating on your unit's data plate or wiring diagram before ordering. If you're unsure of fitment, our HVAC parts specialists can confirm compatibility before you purchase. Order today for same-day shipping.

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 $75
  • 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 C48A203564 | National HVAC Parts?
Yes. This is the factory-specified OEM transformer for the Carrier C48A203564 | National HVAC Parts. 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 C48A203564 | National HVAC Parts?
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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