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Lennox

OEM Lennox Transformer 24V — 19W88

SKU: LNX-19W88 Brand: Lennox
$29.95 $39.95

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Texas CMBL #19328542014
SAM.gov Registered
Govt POs Accepted

The genuine OEM Lennox 19W88 transformer steps down incoming line voltage to the 24V control voltage that powers your thermostat, control board, gas valve, contactor, and relays. Without a working transformer, none of the low-voltage circuits in your Lennox furnace or air handler can operate — making this a small but mission-critical component.

Common failure symptoms include:

  • Blank or unresponsive thermostat
  • System completely dead with no response to a call for heat or cool
  • Blown control-circuit fuse on the board
  • Buzzing, humming, or a burnt smell from the transformer
  • Intermittent operation as the transformer breaks down under load

Why OEM matters: The 19W88 is rated to the exact VA capacity and voltage taps required by your Lennox equipment. An undersized or mismatched aftermarket transformer can overheat, trip fuses, or fail to supply enough current to hold in the gas valve and relays. Choosing the authentic Lennox part ensures proper mounting, correct wiring connections, and dependable long-term performance. Verify the part number and voltage rating against your original before installing.

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 Lennox OEM Lennox Transformer 24V — 19W88?
Yes. This is the factory-specified OEM transformer for the Lennox OEM Lennox Transformer 24V — 19W88. 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 Lennox OEM Lennox Transformer 24V — 19W88?
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 Lennox 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 Lennox 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
HVAC Parts Specialist — Online