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OEM Carrier Transformer 40VA 120V/24V for C48A903564
Carrier

OEM Carrier Transformer 40VA 120V/24V for C48A903564

SKU: CARRIE-C48A903564-TRANSFORMER-HT01BD702 Brand: Carrier

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Texas CMBL #19328542014
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Govt POs Accepted

OEM Carrier Control Circuit Transformer 40VA for Model C48A903564

This OEM replacement transformer (part number HT01BD702) is the factory-specified control circuit transformer for the Carrier C48A903564 packaged unit. The transformer steps down line voltage from 120V to the 24V AC signal required to power the thermostat, control board, and all low-voltage safety circuits. When this component fails, the entire control circuit goes dead — the thermostat display may go blank, the system will not respond to any calls for heating or cooling, and nothing will operate despite power being present at the unit.

  • Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | Factory-matched OEM design | Replaces OEM part number HT01BD702
  • OEM vs Generic: This factory OEM transformer is wound to exact VA and voltage specifications for the C48A903564 control board. Undersized or off-tolerance generic transformers can overload under simultaneous relay demand, causing nuisance tripping or premature control board failure.
  • Install difficulty: 2/5 — Shut off all power to the unit before servicing. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Label all low-voltage wiring before disconnecting. Verify 24V output with a multimeter after installation before restoring full power.
  • Warranty: 1-year OEM factory warranty against defects in materials and workmanship. In-stock and ships same business day from our warehouse.

Compatibility: Designed as a direct OEM replacement for the Carrier C48A903564 packaged unit. Always verify your unit's control circuit voltage and VA requirements against your data plate before ordering. Our parts specialists are available to confirm fitment prior to purchase — order with confidence and get your system back online fast.

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 C48A903564?
Yes. This is the factory-specified OEM transformer for the Carrier C48A903564. 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 C48A903564?
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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