How do I replace the Relay Board in my Machine?

How to Replace the Relay Board in a Modular Harvest Right Freeze Dryer

Video walkthrough: Watch here

What You’ll Need

  • 1/8 inch Allen wrench or drill
  • Phillips screwdriver
  • Needle nose pliers or small adjustable wrench

Step-by-Step Instructions

1. Remove the Module from Your Freeze Dryer

  • Make sure all panels are removed. (If you need help, see Harvest Right’s panel removal videos.)
  • Disconnect all quick disconnects attached to the module.
  • Remove the grounding wire from the freeze dryer end using a 1/8 inch Allen wrench, leaving it attached to the module.
  • Use a Phillips screwdriver to remove the screws holding the serial connector in place.
  • Carefully pull the module out so you can work on it on a table.

2. Remove the Capacitor (If Present)

  • If your module has a capacitor, use needle nose pliers or an adjustable wrench to loosen and remove the bolt holding it in place.
  • Set the capacitor aside. (If your module does not have a capacitor, skip this step.)

3. Remove the Protective Casing (If Present)

  • If your module has a white protective case, remove the screws holding it in place.
  • Pull back the tab and lift up from the front to remove the casing.
  • If your module does not have this case, skip this step.

4. Transfer Wires from the Old Relay Board to the New Relay Board

  • Remove the gray ribbon cable by gently wiggling it side to side until it pops out.
  • Disconnect the capacitor wires from the spare relay (if present) and set them aside.
  • Move each wire one at a time from the old relay board to the new relay board:
    • Ground wire: Remove and attach to the new board.
    • Power wires: White wire goes on the right, black wire on the left.
    • Condenser relay wires: Move to the same location on the new board.
    • Vacuum relay wires: Move to the same location on the new board.
    • Heat relay wires: Move to the heater prongs on the new board.
    • Cable connector: Move to the same spot on the new board.
    • Tray temperature sensor (J17): Move to J17 on the new board.
    • Room temperature sensor (J18, if present): Move to J18 on the new board.
  • Make sure all wires are fully seated and connected.

5. Remove the Old Relay Board from the Bracket

  • Remove the grounding screw and brass bolt (bottom right corner) and set aside.
  • Pinch and release the three white plastic clips in the other corners to free the board.
  • Remove any small plastic spacers and set them aside for reuse.

6. Install the New Relay Board onto the Bracket

  • Position the new relay board on the bracket.
  • Insert the plastic spacers between the board and the bracket as needed.
  • Secure the board with the grounding screw and brass bolt in the bottom right corner.
  • Press the board down onto the three white plastic fasteners in the other corners until it clicks into place.
  • Double-check that the board is secure and not touching the bracket directly (to prevent electrical arcing).

7. Connect the Solid State Relay (If Applicable)

  • Make sure the wiring connection at J5 is connected to your solid state relay port.
  • If needed, remove the two Phillips screws from your solid state relay board to disconnect old wiring and connect new wiring.

8. Reconnect the Gray Ribbon Cable

  • Plug the gray ribbon cable into the new relay board, making sure the pink line is on top (when viewing the board correctly).

9. Reattach the Protective Casing (If Present)

  • Carefully put the white casing back on, making sure not to pinch any wires.
  • Align the casing with the holes and secure it with screws.

10. Reinstall the Capacitor (If Present)

  • Attach the capacitor back onto the bracket and tighten it securely.

11. Reinstall the Module

  • Insert the modular electronics back into your freeze dryer.
  • Reconnect all quick disconnects and the grounding wire.
  • Reattach the serial connector and any panels you removed.

You’re done! Your relay board is now replaced and your modular electronics are ready to use. If you have any questions or run into issues, contact Harvest Right Customer Support for assistance.

How to Replace the Relay Board in a Gen 3 Harvest Right Freeze Dryer

Video walkthrough: Watch here

What You’ll Need

  • Phillips screwdriver (or Phillips bit for a drill)

Step-by-Step Instructions

1. Unplug and Power Off

  • Make sure your freeze dryer is powered off and unplugged from the wall before starting.

2. Remove the Top Panel

  • Remove the top panel to access the relay board. (If you need help, refer to the Harvest Right video on panel removal.)

3. Locate the Relay Board

  • Find the large green relay board in the top left or right corner of your freeze dryer (location depends on your model).
  • This guide is for models without slide-out modular electronics.

4. Prepare the New Relay Board

  • If your new relay board comes attached to a silver bracket, remove it from the bracket.
  • You will install the new board onto the existing bracket inside your freeze dryer.

5. Move Wires One at a Time

  • Move each wire from the old board to the new board one at a time to avoid confusion.
    • Tip: Take a photo of the wiring before you start for reference.
    • Power wires: White wire goes on the right, black wire on the left.
    • Condenser relay wires: Move to the same spot on the new board.
    • Vacuum relay wires: Move these over one at a time.
    • Heater relay wires: Move these next (this relay often fails, which is why you may be replacing the board).
    • Vacuum sensor cable: Move this to the new board.
    • Tray temperature sensor: Move from J17 on the old board to J17 on the new board.
    • Room temperature (ambient) sensor (if present): If you have a wire in J18, move it to J18 on the new board. If not, skip this step.
    • Grounding wire: Leave the grounding wire attached to the metal bracket; you do not need to move it.

6. Remove the Gray Ribbon Cable

  • Carefully unplug the gray ribbon cable from the old board.
  • Make sure the notch/key on the cable lines up correctly when plugging into the new board.Incorrect insertion can damage your electronics.

7. Remove the Old Relay Board

  • Use a Phillips screwdriver to remove the single screw holding the relay board to the bracket (bottom right corner when viewed from the back).
  • The other three corners are held by white clips—gently pull the board off these clips.
  • Hold onto the small spacer and gold piece under the board so they don’t fall and get lost.

8. Install the New Relay Board

  • Line up the new relay board with the three white clips and press it into place.
  • Insert the spacer and gold piece under the board.
  • Secure the board with the screw in the bottom right corner.

9. Reconnect the Gray Ribbon Cable

  • Plug the gray ribbon cable into the new board, making sure the notch/key is aligned correctly.

10. Final Checks

  • Double-check that all wires are securely connected and in the correct locations.

11. Reset the Shelving Unit (if needed)

  • If you replaced the relay board due to a heating issue, press the reset button (thermal overload switch) on the back of your shelving unit. If this button is tripped, your shelves will not heat even with a new relay board.

You’re Done!

  • Your Relay Board is now replaced. Plug in and power on your freeze dryer to resume normal operation.

Tip: If you have any trouble or questions, contact Harvest Right Customer Support for assistance.

 

Find Harvest Right in stores