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OEM Carrier Transformer 40VA 120V to 24V for C4850C50AW03651 | National HVAC Parts
Carrier

OEM Carrier Transformer 40VA 120V to 24V for C4850C50AW03651 | National HVAC Parts

SKU: CARRIE-C4850C50AW03651-TRANSFORMER-HT01BD236 Brand: Carrier

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Texas CMBL #19328542014
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Govt POs Accepted

OEM Carrier Transformer 40VA 120V/24V for Model C4850C50AW03651

This OEM replacement transformer (part number HT01BD236) is the factory-specified control circuit transformer for the Carrier C4850C50AW03651 packaged unit. Its job is to step down line voltage (120V) to the 24V AC signal that powers your thermostat, control board, contactor coil, and all low-voltage control functions. When this transformer fails, the entire control circuit goes dead — your thermostat will appear unresponsive, the system will not call for heating or cooling, and in many cases the unit will simply do nothing at all. Replacing a failed transformer is one of the fastest ways to restore full system operation without replacing more expensive downstream components.

  • Specs: Input 120V AC | Output 24V AC | 40VA rating | OEM part number HT01BD236 | Factory-matched to Carrier C4850C50AW03651 control circuit specifications
  • OEM vs Generic: This is a genuine OEM Carrier transformer wound to exact factory VA and voltage tolerances. Generic transformers may be under-rated in VA, causing them to overheat under normal HVAC control loads and fail prematurely — or damage connected control boards.
  • Install difficulty: 2/5 — Shut off all power to the unit at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter, wire nuts or spade connectors. Photograph existing wiring connections before removing the old transformer. Verify 0V at terminals before touching any wires.
  • Warranty: 1-year OEM factory warranty against defects. In-stock and ships same business day from our NationalHVACParts.com warehouse.

Compatibility: Designed and factory-matched for the Carrier C4850C50AW03651 packaged unit. Verify your existing transformer's input/output voltage and VA rating on the unit data plate or old transformer label before ordering. If you're unsure of fitment, our HVAC parts specialists are available to confirm compatibility before you buy — just reach out with your model and serial number. Order today and most in-stock parts ship the same business day.

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 C4850C50AW03651 | National HVAC Parts?
Yes. This is the factory-specified OEM transformer for the Carrier C4850C50AW03651 | 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 C4850C50AW03651 | 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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