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OEM Carrier Transformer 40VA 120V/24V for C48A903064 — HT01BD702
Carrier

OEM Carrier Transformer 40VA 120V/24V for C48A903064 — HT01BD702

SKU: CARRIE-C48A903064-TRANSFORMER-HT01BD702 Brand: Carrier

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Texas CMBL #19328542014
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Govt POs Accepted

OEM Carrier Control Transformer 40VA for Model C48A903064 — Part HT01BD702

This is the factory OEM replacement control transformer (part# HT01BD702) for the Carrier C48A903064 packaged unit. The transformer steps down 120V line voltage to the 24V signal voltage required by your thermostat, control board, contactor coil, and all low-voltage accessories. When this transformer fails, the entire control circuit goes dark — your thermostat will appear dead, the system won't respond to any calls for heating or cooling, and no safety or diagnostic functions will operate.

  • Specs: 40VA rating | 120V primary / 24V secondary | Class 2 control transformer | Factory-matched to Carrier C48A903064 wiring harness and board interface
  • OEM vs Generic: OEM transformers from Carrier are wound to exact VA and voltage tolerance specifications. Undersized or off-tolerance generic transformers can overheat, trip internal breakers, or cause erratic low-voltage behavior that's difficult to diagnose and can damage downstream components.
  • Install difficulty: 2/5 — Always disconnect power at the disconnect box and breaker before beginning work. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Label all low-voltage wires before removal. Verify 24V output with a multimeter after installation before restoring full power.
  • Warranty: 1-year OEM factory warranty against defects. Ships same business day from our climate-controlled warehouse.

Compatibility: Designed and factory-specified for the Carrier C48A903064 packaged unit. Cross-reference OEM part number HT01BD702 against your unit's data plate and wiring diagram before ordering. Not sure it fits? Our HVAC parts specialists verify fitment before every order — reach out and we'll confirm. In stock and ships 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 $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 C48A903064 — HT01BD702?
Yes. This is the factory-specified OEM transformer for the Carrier C48A903064 — HT01BD702. 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 C48A903064 — HT01BD702?
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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