What are the specs for this Control Board?

The correct replacement for Tempstar model T4H418GKA100 — Heat Pump | Ships Today is this exact part. It is the factory-specified replacement with exact OEM specifications. Using a part with different specifications can cause equipment damage or void your warranty. You can verify this by checking the data plate on your Tempstar equipment which lists the model number T4H418GKA100 — Heat Pump | Ships Today.

Is this control board compatible with Bryant or Payne systems too?

Many Tempstar parts are cross-compatible with Bryant and Payne systems since all three brands are manufactured by Carrier Global Corporation. The same physical part is often used across multiple brand labels with different model numbers. To verify cross-compatibility, check your Bryant or Payne equipment service manual for cross-compatible part numbers, or contact info@nationalhvacparts.com with your model number for confirmation.

Tempstar

Tempstar Defrost Control Board for T4H418GKA100 — Heat Pump | Ships Today

Name: Tempstar Defrost Control Board for T4H418GKA100 — Heat Pump | Ships Today
Brand: Tempstar
SKU: 1173636-GEN
Price: 145.00 USD
Availability: InStock

SKU: 1173636-GEN Brand: Tempstar

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Overview

This OEM defrost control board (part 1173636) is the electronic brain that manages the defrost cycle on the Tempstar T4H418GKA100 heat pump. In heating mode, frost accumulates on the outdoor coil; the defrost board monitors time and coil temperature (via the defrost sensor), then periodically reverses the system to melt that frost — energizing the reversing valve, shutting the outdoor fan, and bringing on auxiliary heat to temper the supply air. When this board fails, the heat pump can ice over completely, lose heating capacity, short-cycle, or run constant emergency heat and spike the electric bill. Because it controls the reversing valve and fan relays, a failed board often presents as multiple unrelated-looking symptoms at once.

Specifications

Spec	Value
OEM Part Number	1173636
Type	Defrost Control Board
Brand	Tempstar (ICP / Heil)
Function	Defrost timing, reversing valve & fan control
Application	Heat Pump Outdoor Unit

Compatibility

Built for the Tempstar T4H418GKA100 heat pump and shared ICP/Heil/Comfortmaker platforms using the 1173636 defrost board. Confirm the part number printed on your existing board and match the connector layout before installing.

Installation Guide

Safety First — Disconnect power at the breaker and outdoor disconnect; verify zero voltage with a multimeter.
Access — Remove the control compartment access panel.
Document — Photograph every plug and wire location on the existing board before touching anything.
Remove — Unplug each connector, release the board standoffs or screws, and lift out the failed board.
Install — Mount the new board and transfer each connector to the matching terminal per your photo, including the defrost sensor lead.
Test — Restore power and initiate a forced/test defrost to confirm the valve, fan, and aux-heat outputs sequence correctly.

Signs You Need a Replacement

Outdoor coil ices over and the unit never defrosts
Heat pump stuck running auxiliary/emergency heat
Defrost cycles too often or never initiates
No response from reversing valve or outdoor fan during defrost

Shipping & Returns

Ships same day before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.

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

Tempstar Defrost Control Board f...

$145.00

Frequently Asked Questions

Does this Control Board fit my Tempstar T4H418GKA100 — Heat Pump | Ships Today?

Yes. This is the factory-specified OEM control board for the Tempstar T4H418GKA100 — Heat Pump | Ships Today. 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 control board on my Tempstar T4H418GKA100 — Heat Pump | Ships Today?

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.

Is this control board compatible with Bryant or Payne too?

Many Tempstar 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 Tempstar control board?

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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