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OEM Carrier Transformer 40VA 120V to 24V for C48A305064 | HT01BD702 | National HVAC Parts
Carrier

OEM Carrier Transformer 40VA 120V to 24V for C48A305064 | HT01BD702 | National HVAC Parts

SKU: CARRIE-C48A305064-TRANSFORMER-HT01BD702 Brand: Carrier

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Texas CMBL #19328542014
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Govt POs Accepted

OEM Carrier Control Transformer 40VA 120V/24V for Model C48A305064 — Part HT01BD702

This is the OEM factory-replacement control transformer (part number HT01BD702) for the Carrier C48A305064 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 system controls. When this transformer fails, the entire control circuit goes dead — your thermostat will be unresponsive, the system won't heat or cool, and no error codes will display because the board itself has no power. It is one of the first components to check when a unit is completely unresponsive.

  • Specs: Primary voltage: 120VAC | Secondary voltage: 24VAC | VA rating: 40VA | OEM part number: HT01BD702 | Factory-matched for Carrier C48A305064
  • OEM vs Generic: This OEM transformer is wound to exact factory VA and voltage specifications. Generic transformers with undersized VA ratings can overheat under normal HVAC control loads, leading to premature failure and nuisance tripping of the secondary fuse.
  • Install difficulty: 2/5 — Disconnect power at the disconnect box and verify zero voltage with a multimeter before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade terminals. Label all wires before disconnecting. Secondary fuse should also be inspected and replaced if blown.
  • Warranty: 1-year OEM factory warranty against defects. In stock and ships same business day from our HVAC parts warehouse.

Compatibility: Designed as a direct OEM replacement for the Carrier C48A305064 packaged unit. Always verify your existing transformer's primary/secondary voltage and VA rating against your unit's data plate before ordering. Our parts specialists are available to confirm fitment — order with confidence and get back up and running today.

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 C48A305064 | HT01BD702 | National HVAC Parts?
Yes. This is the factory-specified OEM transformer for the Carrier C48A305064 | HT01BD702 | 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 C48A305064 | HT01BD702 | 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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