Nordic ATWC Series, Installation And Service Manual, Page: 70 / 106

PRELIMINARY: 24-Sep-2021 Page 70 002536MAN-00
Control Board Replacement Procedure
1. Turn the power off to the unit.
2. Take a picture of the control board and connectors for reference. The picture in
Appendix A may also be helpful.
3. Carefully remove all green terminal strips on the left side, the right side and the bottom of the control board. They
pull straight off the board, with no need to disconnect wires from their screw terminals. You may need to wiggle
them from both ends for the 8 pin ones.
4. Remove the red six pin display board connector from the left side of the control board (marked DISPLAY on the
board).
5. Remove all connectors from the top of the control board. Each connector (or wire) should be marked already from
the factory, e.g. HPS1, LP1, TS1, etc.. This matches the marking on the control board.
6. The control board is held in place at its four corners. Squeeze each standoff by hand or with needle nose pliers if
necessary and carefully pull the corner of the board off of the standoff.
7. Once the control board has been removed, if there are any other standoffs left (they have the bottom snap cut off)
remove them as well.
8. Carefully remove the new control board from the static bag it was shipped in. Place any cut off standoffs from the
old board into the same locations on the new board.
9. Align the control board with the four corner standoffs in the electrical box then push on each corner until they snap in
place.
10. Connect the top connectors to the control board. Refer to the Step 2 picture if necessary for proper locations.
Note that the connector with the resistor (no cable) goes on CTS .
Note that the connector to the left of CTS is marked HTS on older boards, and ODTS on newer boards.
11. Check each of the connectors from Step 10 to ensure they are properly aligned and that no pins are showing.
12. Connect the green terminal strips to the left side, right side and bottom of the control board. Refer to the
Step 2 pic-
ture if necessary for locations.
13. Turn the power on to the heat pump. Ensure the LCD display comes on. Note the firmware version. After EEV ze-
roing and Random Start countdown the display should begin alternating data.
14. If the replacement control board was pre-configured for this unit at the factory then the system is ready for operation.
If it was not then use the PC App corresponding to the unit’s firmware version to configure the unit. Refer to the
Tools -> Configuration menu in the PC APP section.