Replacement driver for Honeywell CL15AE

A few years back I purchased Honeywell CL15AE evaporative air cooler and it is15L indoor air cooler manufactured by JMATEK (for Honeywell). Sine last week this cooler became dead, and the only thing which I can see live is its red color power indicator.

After disassembling the unit I see that most of the components of the controller PCB are rusted and damaged. As I observed the main reason for corrosion is the absence of protective varnish on the top side of the PCB.

The original control board of CL15AE cooler.

At first, I restore all the damaged parts in the PCB with new parts, which including SS8050, SS8550, transistors and a few of electrolytic capacitors. After replacing those components, the unit starts to beep during power up but failed to power on.

Damaged SS8050 and SS8550 transistors.

After some tests, I figured out the problem is in SONiX SN8P2602 8-bit microcontroller. Due to unavailability of microcontroller and it's firmware I decided to produce a replacement, open-source driver for this cooler with generally available electronic components.

The replacement controller which designed for CL15AE is built around Microchip's PIC16F819 microcontroller. This is a low-cost, 8-bit microcontroller with programmable internal oscillator, 16 GPIO pins, and with 3.5KB flash memory. I build this controller as much as similar to the original board and the only major modification which I did is introduce isolation between the AC mains line and a controller circuit. To introduce this separation I use 12V SMPS as a power source and optoisolators to control the two TRIACs.

PIC16F819 based replacement driver board.

In replacement PCB all the LEDs, buttons and mounting holes, are placed in the same positions as the original PCB. Thanks to the EEPROM of the PIC16F819 MCU this board can memorize all the settings made by the user. Due to lack of EEPROM, this feature is not available with SN8P2602 based original controller board.

Compare with the original board this replacement board does not have an IR sensor to capture remote control signals. I didn't get a chance to implement this feature into this new board due to the damaged remote control. Unlike the main control board, the remote control PCB is damaged beyond repair.

The damaged remote control unit.

I test this replacement board with my Honeywell CL15AE cooler for nearly a week and it performs almost similar as original board. To install this board I didn't do any modifications to the cooler and this board can immediately be fixed into the assembly.

This is an open-source hardware project. All the design files, source codes, and documentation are available at github.com.

This PCB has a direct connection with the AC mains voltage and makes sure to take all necessary precautions while assembling, testing and installing this board. Improper connection or short-circuits would cause lethal shock or fire!

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