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OEM Carrier Transformer 40VA 120V/24V for C48A503561
Carrier

OEM Carrier Transformer 40VA 120V/24V for C48A503561

SKU: CARRIE-C48A503561-TRANSFORMER-HT01BD236 Brand: Carrier

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Texas CMBL #19328542014
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OEM Carrier Control Transformer 40VA for Model C48A503561

This OEM Carrier control transformer (part# HT01BD236) is the factory-specified replacement for the Carrier C48A503561 packaged unit. The transformer steps down 120V line voltage to 24V AC to power the low-voltage control circuit — including the thermostat, contactor coil, and control board. When the transformer fails, the entire control circuit goes dark: the thermostat becomes unresponsive, the system won't call for heating or cooling, and no error codes will display because the board itself has lost power.

  • Specs: 40VA rated | 120V primary / 24V secondary | OEM part number HT01BD236 | Factory-matched impedance and thermal protection for safe, reliable operation
  • OEM vs Generic: OEM transformers feature factory-calibrated VA ratings and built-in thermal cutoffs that match the original design specifications. Generic units often lack proper thermal protection, risking repeated failures or downstream board damage.
  • Install difficulty: 2/5 — Disconnect power at the breaker before beginning work. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Label or photograph all wire connections before removing the old unit. Confirm 24V output with a multimeter after installation before restoring full power.
  • Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier C48A503561 packaged unit. Always verify primary voltage (120V), secondary voltage (24V), and VA rating on your unit's data plate or wiring diagram before ordering. Our fitment team is available to confirm compatibility before you purchase — just reach out before placing your order.

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 C48A503561?
Yes. This is the factory-specified OEM transformer for the Carrier C48A503561. 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 C48A503561?
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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