What are the specs for this Transformer?

The correct replacement for Carrier model C48A203551 — Ships Today is this exact part. It is the factory-specified replacement with exact OEM specifications. Using a part with different specifications can cause equipment damage or void your warranty. You can verify this by checking the data plate on your Carrier equipment which lists the model number C48A203551 — Ships Today.

Is this transformer compatible with Bryant or Payne systems too?

Many Carrier parts are cross-compatible with Bryant and Payne systems since all three brands are manufactured by Carrier Global Corporation. The same physical part is often used across multiple brand labels with different model numbers. To verify cross-compatibility, check your Bryant or Payne equipment service manual for cross-compatible part numbers, or contact info@nationalhvacparts.com with your model number for confirmation.

Carrier

OEM Carrier 40VA 120V to 24V Control Transformer for C48A203551 — Ships Today

Name: OEM Carrier 40VA 120V to 24V Control Transformer for C48A203551 — Ships Today
Brand: Carrier
SKU: CARRIE-C48A203551-TRANSFORMER-HT01BD236
Price: 47.25 USD
Availability: InStock

SKU: CARRIE-C48A203551-TRANSFORMER-HT01BD236 Brand: Carrier

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OEM Carrier 40VA Control Transformer HT01BD236 for Model C48A203551

This OEM replacement transformer (part number HT01BD236) is the factory-specified control circuit transformer for the Carrier C48A203551 packaged unit. The transformer steps down line voltage (120V) to the 24V low-voltage signal used by your thermostat, contactor coil, and control board. When it fails, the entire control circuit goes dead — the thermostat goes blank, the system refuses to respond to any call for heating or cooling, and no components energize. A failed transformer is often the first suspect when nothing works at all.

Specs: 40VA rated | Primary: 120V | Secondary: 24V | Industry-standard footprint | OEM part number HT01BD236
OEM vs Generic: This factory OEM transformer is wound to exact VA and voltage tolerances required by the C48A203551 control circuit. Generic transformers with undersized VA ratings can overheat under full control-circuit load, leading to repeated failures and potential board damage.
Install Difficulty: 2/5 — Disconnect power at the breaker and verify with a multimeter before touching any wiring. Tools needed: flathead and Phillips screwdrivers, wire nuts or quick-connect terminals, multimeter. Label all wires before disconnecting. Output should read 24–28V AC when energized.
Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier C48A203551 packaged unit. Verify primary voltage (120V) and VA rating on your existing transformer's label before ordering. If your unit runs a 208/240V primary, do not use this part — contact our team to confirm fitment. Our HVAC parts specialists are available to verify compatibility before you order — get the right part the first time and have your system back up 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 $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

OEM Carrier 40VA 120V to 24V Con...

$47.25

Frequently Asked Questions

Does this Transformer fit my Carrier C48A203551 — Ships Today?

Yes. This is the factory-specified OEM transformer for the Carrier C48A203551 — 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 C48A203551 — 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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OEM Carrier 40VA 120V to 24V Control Transformer for C48A203551 — Ships Today

OEM Carrier 40VA Control Transformer HT01BD236 for Model C48A203551

Shipping Information

Return Policy

Frequently Asked Questions