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OEM Carrier Transformer 40VA 120V to 24V for C4850C50AY03551 — Ships Today
Carrier

OEM Carrier Transformer 40VA 120V to 24V for C4850C50AY03551 — Ships Today

SKU: CARRIE-C4850C50AY03551-TRANSFORMER-HT01BD236 Brand: Carrier
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Texas CMBL #19328542014
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OEM Carrier Control Transformer 40VA 120V/24V for Model C4850C50AY03551

This is the factory OEM replacement transformer (part number HT01BD236) for the Carrier C4850C50AY03551 packaged unit. The transformer steps down line voltage from 120V to 24V AC to power the low-voltage control circuit — including the thermostat, contactor coil, gas valve, and control board. When it fails, the entire control circuit goes dead: the thermostat goes blank, the system won't respond to any call for heating or cooling, and there are no error codes because the board itself has no power.

  • Specs: 40VA rating | 120V primary / 24V secondary | OEM part number HT01BD236 | Factory-matched output voltage and VA capacity for reliable control circuit operation
  • OEM vs Generic: OEM transformers are wound to exact factory VA tolerances, preventing overload tripping and premature failure caused by undersized aftermarket windings common in generic alternatives.
  • Install difficulty: 2/5 — Disconnect all power before servicing. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Verify 24V output with a meter before reassembling the unit. Always label wires before disconnecting the old transformer.
  • Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: This transformer is the specified OEM replacement for the Carrier C4850C50AY03551 packaged unit. If you are unsure whether this part fits your specific unit configuration, verify the part number on your existing transformer's label or contact our fitment team before ordering. Orders placed before 3PM EST ship same 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 $99
  • 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 C4850C50AY03551 — Ships Today?
Yes. This is the factory-specified OEM transformer for the Carrier C4850C50AY03551 — Ships Today. 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 C4850C50AY03551 — Ships Today?
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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