What are the specs for this Transformer?

The correct replacement for Carrier model C4850C48AY05051 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 C4850C48AY05051.

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 Transformer 40VA 120V-24V for C4850C48AY05051

Name: OEM Carrier Transformer 40VA 120V-24V for C4850C48AY05051
Brand: Carrier
SKU: CARRIE-C4850C48AY05051-TRANSFORMER-HT01BD236
Price: 47.25 USD
Availability: InStock

SKU: CARRIE-C4850C48AY05051-TRANSFORMER-HT01BD236 Brand: Carrier

✓ Guaranteed to fit C4850C48AY05051 — or your money back. Terms

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OEM Carrier Control Transformer 40VA for Model C4850C48AY05051

This OEM replacement transformer (part# HT01BD236) is the factory-specified step-down transformer for the Carrier C4850C48AY05051 packaged unit. The transformer converts 120V line voltage to the 24V AC signal that powers your thermostat, control board, contactor coil, and all low-voltage control circuits. When it fails, the entire control circuit goes dark — the thermostat goes blank, the system stops responding to calls for heating or cooling, and in some cases a blown fuse or tripped breaker on the secondary side is the first clue. Replacing this OEM unit restores full low-voltage function quickly and reliably.

Specs: 40VA rated | Primary: 120V AC | Secondary: 24V AC | Factory-matched impedance and thermal protection for Carrier C4850C48AY05051 packaged units
OEM vs Generic: OEM transformers (HT01BD236) feature factory-calibrated VA ratings and built-in thermal cutoffs that match Carrier's control board draw exactly. Generic transformers often run undersized, causing overheating and premature failure under full low-voltage load.
Install difficulty: 2/5 — Disconnect all power before servicing. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Confirm 24V output on secondary terminals before reconnecting control wiring. Always discharge and verify zero voltage before handling.
Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed specifically for the Carrier C4850C48AY05051 packaged unit. Verify primary voltage (120V) and VA rating on your unit's data plate before ordering. OEM part number HT01BD236 cross-references directly to this model. Our fitment team is available to confirm compatibility before you order — don't let a failed transformer take your system offline any longer than necessary.

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 Transformer 40VA 120...

$47.25

Frequently Asked Questions

Does this Transformer fit my Carrier C4850C48AY05051?

Yes. This is the factory-specified OEM transformer for the Carrier C4850C48AY05051. 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 C4850C48AY05051?

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 Transformer 40VA 120V-24V for C4850C48AY05051

OEM Carrier Control Transformer 40VA for Model C4850C48AY05051

Shipping Information

Return Policy

Frequently Asked Questions