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OEM Carrier Transformer 40VA 120V to 24V for C48A405064 | National HVAC Parts
Carrier

OEM Carrier Transformer 40VA 120V to 24V for C48A405064 | National HVAC Parts

SKU: CARRIE-C48A405064-TRANSFORMER-HT01BD702 Brand: Carrier

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Texas CMBL #19328542014
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OEM Carrier Control Transformer 40VA 120V/24V for Model C48A405064 (HT01BD702)

This OEM replacement control transformer (part number HT01BD702) is the factory-specified unit for the Carrier C48A405064 packaged system. The transformer steps down line voltage from 120V to 24V to power the low-voltage control circuit — including the thermostat, contactor coil, and control board. When the transformer fails, the entire control circuit goes dark: the thermostat goes blank, the system will not respond to any calls for heating or cooling, and no safety safeties or relays can actuate. A failed transformer is one of the most common causes of a completely unresponsive HVAC system.

  • Specs: 40VA rating | Primary: 120V | Secondary: 24V | OEM part number HT01BD702 | Direct factory replacement with matched VA rating and terminal configuration
  • OEM vs Generic: This factory OEM transformer is wound to exact VA and impedance specs for the C48A405064 control circuit. Undersized or off-spec generic transformers can overheat, trip their internal breaker repeatedly, or damage the control board — OEM is the safe choice.
  • Install difficulty: 2/5 — Disconnect all power before servicing. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (verify 24V output after install). Always label low-voltage wiring before removal.
  • Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier C48A405064 packaged unit. Verify your existing transformer's VA rating and primary/secondary voltage on the data plate or wiring diagram before ordering. If your system has been upgraded or modified, confirm the OEM part number HT01BD702 against your unit's wiring schematic. Our fitment team is available to confirm compatibility before you order — same-day shipping on all stocked 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 $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 C48A405064 | National HVAC Parts?
Yes. This is the factory-specified OEM transformer for the Carrier C48A405064 | 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 C48A405064 | 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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