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OEM Carrier Transformer 40VA 120V to 24V for C48A402551 | National HVAC Parts
Carrier

OEM Carrier Transformer 40VA 120V to 24V for C48A402551 | National HVAC Parts

SKU: CARRIE-C48A402551-TRANSFORMER-HT01BD236 Brand: Carrier

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Texas CMBL #19328542014
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Govt POs Accepted

OEM Carrier 40VA Control Transformer HT01BD236 for Model C48A402551

This OEM control transformer (part number HT01BD236) is the factory-specified replacement for the Carrier C48A402551 packaged unit. The transformer steps down line voltage (120V) to the 24V signal needed to power the control board, thermostat circuit, and all low-voltage components. When this part fails, the entire control circuit goes dead — the thermostat shows no response, the system won't call for heating or cooling, and no error codes are displayed because the board itself has no power.

  • Specs: 40VA rated | 120V primary / 24V secondary | Factory-matched OEM replacement | Designed for Carrier C48A402551 packaged unit control circuit
  • OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances required by the Carrier factory control board. Undersized or off-spec generic units can overheat, blow fuses repeatedly, or cause erratic low-voltage behavior that mimics other faults.
  • Install difficulty: 2/5 — Shut off all power before servicing. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Photograph all wiring connections before removal. Verify 24V output with a multimeter after installation before restoring power to the full system.
  • Warranty: 1-year OEM factory warranty against defects. In stock and ships same business day from our warehouse.

Compatibility: Fits Carrier model C48A402551 packaged unit. Always verify your unit's control circuit voltage requirements against your data plate before ordering. If you're unsure of fitment, our HVAC parts specialists are available to confirm compatibility before you buy — no guesswork required.

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 C48A402551 | National HVAC Parts?
Yes. This is the factory-specified OEM transformer for the Carrier C48A402551 | 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 C48A402551 | 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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