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Upgrading to The IQ 2020 Control Box Step-by-Step

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In this post, we are going to give you a detailed tutorial on how to upgrade your spa from the IQ 2000 to the IQ 2020. Switching over to a completely new control system can seem daunting, but have no fear! We will be your tour guide on this hot tub upgrade adventure.

IQ 2020 Control Box Upgrade Overview

If you are the proud owner of a HotSpring Spa built between 1997 and 2000, there’s a good chance you have the (now obsolete) IQ 2000. Some parts are still available for this system, but some key parts are not. If one of those unavailable parts goes bad, you will have no choice but to upgrade to the newer IQ 2020 Control Box.

What You’ll Need to Install the IQ 2020 Control Box


Always use caution when working on electricity. If you feel uncomfortable following these steps at any point, please call a professional.

Step 1: Accessing the Control Box

The first thing you will need to do is turn off the power to your spa. If your spa is wired for 120V, simply unplug the spa from its main power source. If your spa is wired for 240V, you will need to turn your breakers in the spa’s subpanel to the off position.

After this, you will need to use a Phillips screwdriver to remove the four screws for your spa door panel and then remove the door.

After the door panel is removed, locate the control box. Use a Phillips screwdriver to remove the two control box lid screws and remove the box lid.

Step 2: Disconnect Spa Components

After you have access to the circuit boards of the control box, you can now remove the various components plugged into the control box. Make sure you unplug any wire that is coming from the outside and plugging into the circuit boards. (EG: Circ Pump, Jet Pump(s), Heater, Control Panel(s), Spa Light, Thermistors, Switches, Ozonator, Main Power Wires, etc…). You can leave the internally connected wires attached.

Next, use a pair of pliers to squeeze the strain reliefs and pull each cable out of the control box.

Step 3: Remove the Old Control Box

Now that the components are removed from the control box you are free to remove it. Unscrew the two mounting screws and slide the control box to the right to drop it down. Once the box is free, remove any grounding wires that may be connected to the bonding terminal on the side of the control box.

Step 4: Remove the Old Control Head

The next step in the process is to remove the control panel.

NOTE: It is always important to remember that old control panels are not compatible with new control boxes. which is why you must also update your control panel when you update your control box to a newer version.

To remove the control panel, start by removing the clear light cover at the top of your control panel. Remove the two screws found behind that light cover and then lift and pull to release the control panel from the fitting.

Once the control panel is removed, you will have to separate the control panel bezel from the control head. To do this, remove the backplate of the control head. Disconnect all of the wires plugged into the control head circuit board (except for the ribbon cable) and unscrew the 4 mounting screws that connect the control head to the bezel. They should now be free to separate.

Step 5: Install the New Control Head

To install the new control head, you simply reverse Step 4. You will basically put it together the same way you took it apart.

Note: If you have an Auxilary Control Panel, It will not attach to the control head. You will plug it directly into the new IQ 2020 control box.

Step 6: Install the New Spa Light

The old IQ 2000 spa light is not compatible with the IQ 2020 so you will need to upgrade your light. First, let’s remove the old light.

To remove the old light, simply pull the old light bulb out of the metal heat shield, and then unscrew the 3 screws holding the heat shield in place and remove it.

installing your new light can vary depending on when your spa was made. If your spa was made after the year 2000, you can put some silicone around the edge of the light lens and push the light into place. If you have a spa from before the year 2000, you will have to zip tie it to the metal heat shield and then screw the heat shield back into place.

Step 7: Install New Sensors

Your IQ 2020 Control Box (77271) comes with two new sensors (39205 &39204). You need to install these new sensors because the old sensor plugs are not compatible with the new motherboards.

NOTE: Before changing the sensors, either drain the spa or clamp off the hoses to the heater using hose clamp plyers.

To change the sensors, use a pair of plyers to unscrew the old sensors from the heater. Place new o-rings on the new sensors and hand tighten them. After they are tightened by hand, use the pair of plyers to tighten them a little bit further. Be careful not to over tighten them.

Step 8: Install the New IQ 2020 Control Box

It’s finally time to install the new control box! Be sure to reference the instructions that come with your new control box to ensure you are plugging things into the proper places.

Here are the steps to installing the new control box:

  • Push the control box against the metal mounting bracket and slide it to the left.
  • Remove the two screws to the lid of the control box and remove the lid.
  • Use the two stainless steel bracket screws to secure the new control box to the bracket.
  • Connect the control head
  • Connect the Auxilary panel (if you have one)
  • Connect the spa light (both connections)
  • Connect the high-limit and control sensors
  • Use wire cutters to cut the connectors off of the black and white wires of the heater. Then strip away about 3/4 inch of insulation from the wires so that they can be properly installed in the new heater relay board.
  • Install the black wire of the heater into H1 and the white wire into H2 and the ground to the grounding terminal on the heater board.
  • NOTE: To connect wires into the terminal blocks on the heater relay board, insert a small flathead screwdriver into the square opening above the wire and pry up. This should open the “trap door” so you can insert the wire.
  • Tug on the H1 and H2 wire connections to make sure they are secure.
  • Connect the power wires from your subpanel or power cord to the proper terminals on the heater relay board. (See the instructions included with your control box)
  • Install the metal power jumpers (as needed. Again, see your instructions).
  • Configure the Program Jumpers on the motherboard located just below where the “Pressure Switch” plugs in. (See instructions)
  • Reconnect the Jet pump(s), Ozonator, and Circulation Pump in their proper terminals located at the bottom of the motherboard.
  • Place the strain relief clamps back in place for each component that has one.
  • Reinstall the control box lid and secure it down with the two screws.

Step 9: Finishing Up

Double-check that all of your components are back in place and have wires going into the control. If everything looks good, go ahead and power on the spa.

If everything is operating accordingly, you may now reinstall the door panel and start enjoying your new spa!

Backyard Plus is Here to Help You Be the Hero.

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