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Universal Heat Pump Defrost Control Board — Timer/Demand Replacement
National HVAC Parts

Universal Heat Pump Defrost Control Board — Timer/Demand Replacement

SKU: NHVAC-DEF-BOARD Brand: National HVAC Parts
$89.95
Market price $105.82
SAVE $15.87 (15%) vs market
Genuine National HVAC Parts OEM part · Guaranteed to fit your unit

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Texas CMBL #19328542014
SAM.gov Registered
Govt POs Accepted

Universal defrost control board for heat pump systems. Controls the defrost cycle that melts ice buildup on the outdoor coil during cold weather. Compatible with time-initiated/temperature-terminated and demand defrost systems.

Symptoms: Ice building up on outdoor unit, heat pump not heating efficiently in winter, outdoor fan not stopping during defrost, no reversing valve activation.

  • Type: Time/temperature defrost control
  • Voltage: 24V control, 240V switching
  • Timing: Adjustable 30/60/90 min intervals
  • Compatibility: Most residential heat pumps

Install difficulty: 3/5 — Power off. Photo existing wiring. Disconnect wires from old board. Mount new board, reconnect wires. 30 min.

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 $99
  • 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 Defrost Control fit my National HVAC Parts Universal Heat Pump Defrost Control Board — Timer/Demand Replacement?
Yes. This is the factory-specified OEM defrost control for the National HVAC Parts Universal Heat Pump Defrost Control Board — Timer/Demand Replacement. 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 defrost control on my National HVAC Parts Universal Heat Pump Defrost Control Board — Timer/Demand Replacement?
Difficulty: Advanced (1–2 hrs)
Step 1: Turn off breaker. Step 2: PHOTOGRAPH all wire connections before touching anything. Step 3: Label each wire with tape. Step 4: Disconnect all wires, remove old board. Step 5: Mount new board, reconnect all wires matching your photo exactly. Step 6: Restore power and test all modes. Exact part number match is critical.
My HVAC system is completely dead. What could be wrong?
Completely dead HVAC (no LED on board) = failed control board or blown fuse. Check board fuse first (3A or 5A, costs $1–$5). If fuse is good and board has power but no LED, board is dead. Always photograph wiring before replacing.
Will this defrost control fit brands other than National HVAC Parts? +
Cross-brand compatibility varies by part. The safest method is matching the exact OEM part number stamped on your old part. If you are unsure, email info@nationalhvacparts.com with your equipment model number and we will verify the correct replacement before you order.
Should I use OEM or aftermarket for my National HVAC Parts defrost control?
OEM essential. Control boards are model-specific with precise firmware and connector layouts. Aftermarket boards rarely match all functions and can cause intermittent failures or safety issues. Always match the exact OEM part number.
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