Trane BRD04878 Dual Relay Output Board
The Trane BRD04878 is a dual relay output board fitted inside the control panels of Trane chillers. It takes low-voltage command signals from the chiller controller and converts them into relay switching actions that drive connected loads fans, contactors, auxiliary devices and sequencing outputs. When it fails, the controller is issuing commands that never reach the equipment: the logic is fine, the machine simply doesn’t respond.
Two clarifications before you order. This is the output board, not the input board. If your fault is a signal the controller can’t read rather than a load it can’t drive, you need the dual binary input board instead. And Trane specifies that this board requires programming, it is not a drop-in.
Cool.sa supplies BRD04878 as a genuine Trane OEM part, held in stock inside Saudi Arabia alongside our full range of chiller spare parts, with a VAT invoice and delivery to project sites across the Kingdom.
Key Features
- Dual relay output: two independently switched output channels driven by controller commands
- Pluggable connectors: field wiring transfers without cutting or re-terminating
- Converts low-voltage control signals into high-current switching for connected loads
- Genuine Trane OEM, original specification and part marking
- Covers Trane scroll, centrifugal and screw chiller platforms
- Compact and light, so urgent air freight costs almost nothing
Benefits of Using This Product
A failed relay output board produces a fault that reads as a mechanical problem when it isn’t one. The controller commands a fan or a contactor, the command is logged, and nothing happens at the equipment. Teams check the load, the wiring, the contactor coil, the supply, and the actual break is a relay on a board that never closed.
Replacing the board restores the command path at its source. Using the genuine OEM component also means the relay ratings and switching behaviour match what the controller and the connected loads were designed around — no marginal contact rating, no intermittent chatter that surfaces weeks later under full load.
Technical Specifications
| Specification | Value |
| Trane part number | BRD04878 |
| Catalogue description | BOARD; DUAL RELAY OUTPUT, WITH PLUGGABLE CONNECTORS, PROGRAMMING REQUIRED |
| Board type | Dual relay output |
| Output channels | 2 |
| Connectors | Pluggable |
| Programming | Required – configured to the unit |
| Universality | Unit-specific, not universal |
| Approx. weight | 0.4 kg |
| Alternate reference | BRD-4878 |
| Condition | New, genuine Trane OEM |
| Manufacturer | Trane / Trane Technologies (Service First) |
BRD04878 vs BRD04873 — Which One Do You Need?
These two boards sit on opposite ends of the same control chain, and ordering the wrong one is the most common mistake on this part.
| Comparison | BRD04878 | BRD04873 |
| Function | Dual relay output | Dual binary input |
| Direction | Controller → equipment | Equipment → controller |
| What it does | Switches relays to drive loads | Reads two digital input signals |
| Typical symptom | Controller commands a device, nothing happens | Controller can’t see a switch, permissive or interlock |
| Programming | Required | Required |
If the controller isn’t seeing something, you need the input board. If the controller isn’t driving something, this is your part. Browse both under chiller control boards.
Why Buy Your Trane BRD04878 From Cool.sa
- Genuine Trane OEM only: no aftermarket copies of control boards. Original packaging and marking, source documentation on request.
- Stock inside Saudi Arabia: while overseas distributors quote factory-order lead times plus international freight and customs.
- Cross-reference and function confirmation before you order: send a photo and we’ll confirm you need the output board rather than the input board.
- Programming and commissioning support: so the board goes in and works on the same visit.
- VAT invoicing: for corporate, government and private-sector procurement.
- Delivery to project sites: Riyadh, Jeddah, Dammam, Khobar, Jubail, Yanbu, Ras Al Khair.
- Published returns policy on electronic components: no surprises at dispute.
- GCC export quoting: for the UAE, Qatar, Kuwait, Bahrain and Oman.
Frequently Asked Questions
Q1. Is this a genuine Trane part?
Yes. Genuine Trane OEM in original packaging with original part marking. We don’t sell aftermarket copies of this board. Source documentation available on request.
Q2. Does the BRD04878 need programming after installation?
Yes. Trane’s specification states programming is required. The board must be configured to your unit with the service tool before the chiller operates correctly. A board that seems unresponsive after fitting is usually unconfigured, not faulty.
Q3. What’s the difference between BRD04878 and BRD04873?
BRD04878 is a dual relay output board that drives connected loads. BRD04873 is a dual binary input board that reads two digital signals into the controller. They serve opposite ends of the same control chain and are not interchangeable.
Q4. Is this the main chiller control board?
No. It’s an output board. The main control module is a separate component with a different part number.
Q5. Which Trane chillers use it?
CGAM and CXAM scroll chillers, CVGF and CVHG centrifugals, and RTWD screw chillers. Unit specific, so confirm against model and serial.
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