Same-day shipping before 3PM CST · 35,000+ OEM Parts · Texas CMBL & SAM.gov Registered · Government POs Accepted

Menu

Home Shop All Account Cart
OEM Carrier Transformer 40VA 120V/24V for C4850C50AJ02561
Carrier

OEM Carrier Transformer 40VA 120V/24V for C4850C50AJ02561

SKU: CARRIE-C4850C50AJ02561-TRANSFORMER-HT01BD236 Brand: Carrier

OEM Guaranteed

Same-Day Ship

30-Day Returns

Secure Checkout

Texas CMBL #19328542014
SAM.gov Registered
Govt POs Accepted

OEM Carrier Control Transformer 40VA 120V/24V for Model C4850C50AJ02561

This OEM control transformer (Part# HT01BD236) is the factory-specified replacement for the Carrier C4850C50AJ02561 packaged unit. The transformer steps down line voltage from 120V to 24V to power the low-voltage control circuit — including the thermostat, contactor coil, gas valve, and control board. When the transformer fails, the entire control circuit goes dark: the thermostat goes blank, the system will not respond to any call for heating or cooling, and nothing turns on. It is one of the first components to check when a unit shows zero response.

  • Specs: 40VA rating | Primary: 120V | Secondary: 24V | OEM Part# HT01BD236 | Factory-matched for Carrier C4850C50AJ02561 packaged systems
  • OEM vs Generic: This OEM transformer is wound to exact Carrier factory specifications, ensuring precise voltage output and VA capacity. Generic transformers may underperform under full control circuit load, causing nuisance lockouts or premature failure of downstream components like the contactor coil or gas valve.
  • Install difficulty: 2/5 — Disconnect all power to the unit before servicing. Tools needed: flathead and Phillips screwdrivers, multimeter (to verify 24V output after install), wire nuts or quick-connects. Always label or photograph existing wiring before disconnecting. Confirm blown fuse or tripped secondary fuse before condemning the transformer.
  • Warranty: 1-year OEM factory warranty against defects in materials and workmanship. In-stock and ships same business day from our warehouse.

Compatibility: Designed specifically for the Carrier C4850C50AJ02561 packaged unit. Verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate or wiring diagram before ordering. If your secondary fuse repeatedly blows after replacement, inspect downstream components for shorts before reinstalling. Our HVAC parts specialists are available to confirm fitment — order with confidence and get your system back online 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 C4850C50AJ02561?
Yes. This is the factory-specified OEM transformer for the Carrier C4850C50AJ02561. 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 C4850C50AJ02561?
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.
Home Shop Search Account Cart
Fitment Guaranteed
MR
Mike Rivera
HVAC Parts Specialist — Online