What are the specs for this Transformer?

The correct replacement for Carrier model C4850C50AY04151 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 C4850C50AY04151.

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 Transformer 120V-24V for C4850C50AY04151

Name: OEM Carrier 40VA Transformer 120V-24V for C4850C50AY04151
Brand: Carrier
SKU: CARRIE-C4850C50AY04151-TRANSFORMER-HT01BD236
Price: 47.25 USD
Availability: InStock

SKU: CARRIE-C4850C50AY04151-TRANSFORMER-HT01BD236 Brand: Carrier

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OEM Carrier 40VA Control Transformer for Model C4850C50AY04151

This OEM control transformer (part# HT01BD236) is the factory-specified replacement for the Carrier C4850C50AY04151 packaged unit. The transformer steps down 120V primary voltage to 24V to power the low-voltage control circuit — including the thermostat, contactor coil, and all control board logic. When the transformer fails, the entire control circuit goes dead: the thermostat displays nothing, relays won't pull in, and the system will not respond to any call for heating or cooling. A blown secondary fuse or burnt winding smell are the most common failure indicators.

Specs: 40VA rated | 120V primary / 24V secondary | OEM part number HT01BD236 | Factory-matched winding tolerance for stable control voltage
OEM vs Generic: OEM transformers like this HT01BD236 are wound to exact VA and voltage specifications for the Carrier C4850C50AY04151 control circuit. Generic units often run undersized VA ratings, causing voltage sag under load that leads to erratic relay behavior and premature board failure.
Install difficulty: 2/5 — Disconnect power at the disconnect box and confirm zero voltage with a multimeter before handling. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Note wire color and terminal labeling before disconnecting the old unit.
Warranty: 1-year OEM factory warranty. In stock and ships same business day from our NationalHVACParts.com warehouse.

Compatibility: Designed specifically for the Carrier C4850C50AY04151 packaged unit. Always verify primary voltage (120V) and VA rating on your unit's data plate before ordering. If your 24V fuse keeps blowing after transformer replacement, check for shorted control wiring downstream before installing the new part. Our fitment team is available to confirm compatibility before you order — 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 $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 Transformer 120...

$47.25

Frequently Asked Questions

Does this Transformer fit my Carrier C4850C50AY04151?

Yes. This is the factory-specified OEM transformer for the Carrier C4850C50AY04151. 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 C4850C50AY04151?

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 Transformer 120V-24V for C4850C50AY04151

OEM Carrier 40VA Control Transformer for Model C4850C50AY04151

Shipping Information

Return Policy

Frequently Asked Questions