What are the specs for this Control Board?

The correct replacement for Tempstar model T4A418GKD200 — Diagnostic Module | 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 T4A418GKD200 — Diagnostic Module | 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 ComfortAlert Control Board for T4A418GKD200 — Diagnostic Module | Ships Today

Name: Tempstar ComfortAlert Control Board for T4A418GKD200 — Diagnostic Module | Ships Today
Brand: Tempstar
SKU: 1177402-GEN
Price: 189.95 USD
Availability: InStock

SKU: 1177402-GEN Brand: Tempstar

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Overview

This is a genuine OEM ComfortAlert diagnostic control board (OEM part number 1177402) for the Tempstar T4A418GKD200 condensing unit. The ComfortAlert module continuously monitors compressor and system operation — voltage, current, run/lock-out cycles — and reports faults through a flashing LED code, giving technicians fast, accurate diagnostics without back-and-forth troubleshooting. It also provides protective lock-out logic that guards the compressor against conditions like low voltage, locked rotor, open circuit, and short cycling. Common failure symptoms include no LED activity, false or stuck fault codes, a compressor that won't energize, or erratic system lock-outs. Replacing a failed board restores accurate diagnostics and full compressor protection.

Specifications

Spec	Value
OEM Part Number	1177402
Type	ComfortAlert Diagnostic Control Board
Brand	Tempstar
Control Voltage	24 V
Function	Compressor monitoring, fault-code diagnostics, protective lock-out
Fits Model	T4A418GKD200

Compatibility

Engineered as a direct-fit replacement for the Tempstar T4A418GKD200 air conditioner. This OEM ComfortAlert board is also used across many ICP/Heil/Tempstar/Comfortmaker units that call for part 1177402. Confirm your unit specifies the ComfortAlert diagnostic module before installing.

Installation Guide

Safety First — Disconnect power at the outdoor disconnect and the breaker, then verify zero voltage at the board terminals with a multimeter.
Access — Remove the service panel from the condensing unit to expose the control board.
Document — Photograph every low-voltage and sensing lead landed on the board before disconnecting.
Remove — Disconnect the wiring, release the board from its standoffs or mounting screws, and lift it out.
Install — Mount the new ComfortAlert board, reconnect each lead to the matching terminal per your photo, and seat all connectors fully.
Test — Restore power, call for cooling, and confirm the LED shows normal operation with no active fault codes and the compressor energizes correctly.

Signs You Need a Replacement

Diagnostic LED is dark or unresponsive on power-up.
False, stuck, or constantly repeating fault codes.
Compressor will not start or repeatedly locks out without cause.
Erratic short-cycling or loss of compressor protection.

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 ComfortAlert Control Bo...

$189.95

Frequently Asked Questions

Does this Control Board fit my Tempstar T4A418GKD200 — Diagnostic Module | Ships Today?

Yes. This is the factory-specified OEM control board for the Tempstar T4A418GKD200 — Diagnostic Module | 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 T4A418GKD200 — Diagnostic Module | 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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