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OEM Carrier Transformer 40VA 120V-24V for FX4DNF019005AAAA
Carrier

OEM Carrier Transformer 40VA 120V-24V for FX4DNF019005AAAA

SKU: CARRIE-FX4DNF019005AAAA-TRANSFORMER-HT01CN241 Brand: Carrier

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Texas CMBL #19328542014
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OEM Carrier 40VA Control Transformer HT01CN241 for Model FX4DNF019005AAAA

This is the OEM factory-specified control transformer (part number HT01CN241) for the Carrier FX4DNF019005AAAA fan coil air handler. The transformer steps down line voltage from 120V to 24V to power the low-voltage control circuit — including the thermostat, contactor coil, and any zone controls. When this transformer fails, the entire control system goes dark: your thermostat goes blank, the system makes no response to a call for cooling or heating, and a voltage check at the secondary terminals will read zero. It is one of the first components to test when diagnosing a completely unresponsive system.

  • Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | Factory OEM part number HT01CN241 | Compact chassis-mount design for air handler installation
  • OEM vs Generic: This OEM transformer is wound and tested to Carrier's exact VA and voltage specifications. Generic transformers frequently underperform at rated VA, causing nuisance tripping of the secondary fuse and premature control board failures under normal load.
  • Install Difficulty: 2/5 — Shut off power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Label all 24V low-voltage wires before disconnecting. Confirm 0V at primary terminals before handling. A straightforward swap for any experienced DIYer or HVAC technician.
  • Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed as the direct OEM replacement for the Carrier FX4DNF019005AAAA fan coil air handler. Always verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate before ordering to confirm fitment. Have a question about compatibility? Our HVAC parts specialists verify fitment before you buy — 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 FX4DNF019005AAAA?
Yes. This is the factory-specified OEM transformer for the Carrier FX4DNF019005AAAA. 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 FX4DNF019005AAAA?
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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