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How To Test A Hot Springs IQ 2020 Heater Relay Board in 7 Simple Steps

Blog Featured Images 39-

How To Test Your IQ 2020 Heater Relay Board

In this post, we are going to teach you how to test a Hot Springs IQ 2020 heater relay board (the heater relay board in your Hotspring Spa’s IQ2020 control box). If your spa is not heating, there is a good chance there could be an issue with the IQ 2020 heater relay board. There are just a handful of simple steps needed to figure out the source of the issue. Follow the steps laid out in this post and you will have your answer in no time!

Heater Relay Board Pre-test checklist:

• Determine which heater relay board generation you have (1st, 2nd, 3rd, or 4th Generation) and find the directions that belong to that version.
• The red “Power” light on the control panel must be on solid and NOT blinking. If it is blinking, contact our helpdesk.
• The green “Ready” light on the control panel should be off.
• The temperature on the control panel must be set higher than what the temperature of the spa water is.
• Have your voltage meter (aka Multi Meter)
• Phillips Screwdriver and needle-nose pliers handy (for testing 1st & 2nd Generation).

Testing 3rd and 4th Generation IQ 2020 Heater Relay Board (for 1st and 2nd Generation Keep Scrolling!)

Step 1
Turn the temperature to the highest setting on the control panel. The temperature on the control panel must be higher than the temperature of the spa water. The green ready light on the control panel should be off.

Step 2
Remove the screws from your equipment compartment door and set the door aside. Then, remove the two small Phillips screws that hold on the front cover of the IQ 2020 Control Box and set the cover aside.

IQ2020 Control box

Step 3
Look at the circuit board (motherboard) on the right and make sure that the two LED lights are lit. The green LIM Ok light and the red HTR ON light. It is important that the red HTR ON light is lit before continuing.
If it’s not, then there is a problem with your motherboard and you will need to troubleshoot with one of our technicians. Please contact us via our helpdesk or call us at (805) 541-9000 or text at (833) 607 3428.

LIM OK HTR ON 800-

Step 4
On the heater relay board, look for the two LED lights D9 (Red) and D10 (Green) on the top. They should both be lit. If D9 is flashing, that is an indication that the heater relay board is bad or needs to be reset with a new motherboard.
*The 3rd Generation (Invensys) heater relay board does not have a D9 or D10 light. If you are testing at 3rd Generation board, please skip to the next step.

d9 and d10 lights 1400x1000 1-

Step 5
Using your multimeter, set the voltage meter higher than 300 ACV. Meters vary in design so you will need to be familiar with yours. Make sure there is a fresh battery in the meter.

Voltage Meter-

Step 6
Put one probe from your voltage meter onto the H1 terminal and the other probe onto the H2 terminal. It will not matter which probe goes onto the H1 and H2.

how to test a hot springs iq 2020 heater relay board

Step 7
Check the reading on your meter. In this test, the spa is wired for 115 volt and the reading is good.

77119 heater board test 5 H1 and H2 115 120 volts-

CONCLUSION

If your voltage reading was lower than 100 volts, then the board is damaged and has to be replaced. It is not repairable. Sometimes you can see visible smoke residue between one or more of the black relays (relays are shown above the probes on the Step 6 picture). The 77119 Heater Relay Board is the newest upgraded beefier heater relay board. The original 73355 & 74618 circuit boards were discontinued.

My voltage reading was zero
If you know for sure that you are making a solid connection between the voltage meter probes and the heater board terminals, a voltage reading of zero indicates that the board has failed and needs to be replaced. You can buy a new heater relay board now or Contact us with any questions you may have.

My spa is wired 240 volts and my voltage reading was between 215 volts-250 volts.
Your heater relay board is okay but your heater may not be. Contact us so we can walk you through the next steps.

Testing 1st & 2nd Generation IQ 2020 Heater Relay Board (Invensys)

Step 1
Remove the screws from your equipment compartment door and set the door aside.

Step 2
Remove the two small Phillips screws that hold on the front cover of the IQ 2020 Control Box and set the cover aside.

IQ2020 Control box

Step 3
Look at the circuit board (motherboard) on the right and make sure that the two LED lights are lit. The green LIM Ok light and the red HTR ON light. It is important that the red HTR ON light is lit before continuing. If it’s not then please contact us.

LIM OK HTR ON 800-

Step 4
Now turn off the power to your spa. Either unplug it if it’s 120-volt model or turn off the breakers if it’s wired 240 volts.

Step 5
Find where the black and white wire from the heater’s power cord connects onto the front of the heater relay board. The black wire should be connected to the P3 terminal and the white wire onto the P2 terminal.

locating heaters power leads 300-

Step 6
With the power OFF to the spa, gently remove the black wire from the P3 terminal and the white wire from the P2 terminal. If the power is still on to the spa, the board will short out when you remove these wires.

disconnecting heater from board 300-

Step 7
Turn the power back on to the spa.

Step 8
Set the voltage meter higher than 300 ACV . Meters vary in design so you’ll need to be familiar with yours. Make sure there is a fresh battery in the meter.

setting voltage meter for 230volt spa 300-

Step 9
Put one probe from your voltage meter onto the P2 terminal and the other probe onto the P3. It won’t matter which probe goes onto the P2 & P3.

voltage meter probes on P2 and P3 flag terminals 300-

CONCLUSION

If your voltage reading was lower than 100 volts, then the board is damaged and has to be replaced. It is not repairable. Sometimes you can see visible smoke residual between one or more of the black relays (relays are shown above the probes on the Step 9 picture). The 77119 Heater Relay Board is the newest upgraded beefier heater relay board. The original 73355 & 74618 circuit boards were discontinued.

My voltage reading was zero
If you know for sure that you are making a solid connection between the voltage meter probes and the heater board terminals, a voltage reading of zero indicates that the board has failed and needs to be replaced. You can buy a new heater relay board now or Contact us with any questions you may have.

My spa plugs into a 120-volt outlet and the voltage reading was between 110 volts-130 volts.
Your heater relay board is okay but your heater may not be. Contact us so we can walk you through the next steps.

My spa is wired 240 volts and my voltage reading was between 215 volts-250 volts.
Your heater relay board is okay but your heater may not be. Contact us so we can walk you through the next steps.



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32 thoughts on “How To Test A Hot Springs IQ 2020 Heater Relay Board in 7 Simple Steps

  1. Hi there, Bruce-
    I sent your message to my technician Paul and here is his reply:

    Are either of your logo lights flashing? If your blue logo light is flashing it means you probably have an airlock. Just, remove the gray standpipe and filter, place the garden hose down inside the standpipe fitting and run it full blast with a rag around the hose to force all air out the circ pump and heater lines. The logo light flashing can mean a number of things, but I’m thinking since you recently refilled your tub, it could be an airlock.

    Do you have any lights on the motherboard? If you have no lights on the motherboard and no display on the topside control but you have good power coming in, you probably have a fried control box and topside. Your blue logo light will be flashing. You will have to replace both of them. Sometimes a power surge can cause the components to go out. Feel free to give us a call 805-541-9000.

    Thanks,
    Rebekah

  2. I am in Oregon. I purchased a Hot Springs Aria HT new in 2015. I recently did a drain and refill – power off at the circuit breakers (with a 20 and a 30 amp breaker), fully drained the tub, refilled the tub, turned the circuit breakers back on. Prior to that the hot tub was working normally. After I did my most recent drain and fill (June 2023) nothing worked – no disply, no heater, no jets…. I had an electrician check the power at the unit and it has power. What did I blow up? Do I have to replace the entire controller system?

  3. Hi Dennis, The clicking sound is probably the heater relays. The red D9 light is the diagnostic light for the heater relay board. When it is solid red it means the board is working and supplying voltage to the heater, but when the red D9 light starts flashing it means the heater board is bad. There will not be any voltage between H1 and H2. You will have to get a new heater board. There is currently no fix for this issue. If your board failed within 12 months of purchase, it qualifies for factory warranty. I would reach out to the dealer that sold it to you and have them process a warranty for the board.

  4. I have a 2004 Hot Springs prodigy serial number H2F1644. This is the third relay I have installed. first one last about 12 years or so the original the second one maybe lasted a year or two the third one I don’t think he even lasted that long. I noticed on D9 the red flashing LED and I noticed in both newer fourth generation relays. I heard a clicking sound quite often I can only assume that it may have worn out the relay. I hope this can be fixed if your technicians can figure this out and get back with me, I would appreciate it. Thank you.

  5. Hi there, Travis
    I have opened a help ticket for you and one of my technicians will get back to you. I’m thinking that based on your serial number, you may have the Cedric (White Label: Invensys) or Eagle (Blue sticker: Made in China) IQ2020 control box. One of my techs will help you figure out what you need.

    Thanks,
    Rebekah

  6. Hi have been reading your trouble shooting methods and its seems pretty easy to check how to test the heater relay board. My only concern is all the boards you have suggested on here are similar to what I have but are not the exact board. How do I know if I’m testing the proper connection to determine if my board is faulty?
    Hot Springs Vista SS SS3P2107
    IQ2020
    3 relays
    240 hook up
    The contact connector is what’s different from most of the boards I have looked up.
    H1 1 2 H2 3 4 5 6 7
    No LED lights on the relay board at all.

    can you try and steer me in the right direction Please.

    Thanks
    Travis

  7. Hi there, Timmithy-
    We’ll need to get your spa serial and more description on which lights are blinking (lights from the mother board?, heater relay board? etc). I’m going to open a ticket for you and have one of my technicians contact you.
    Thanks,
    Rebekah

  8. I have a jet setter tub with the 3rd gen board I replaced the heater which wasn’t working but both the red and green lights were lit. After installing the new heater and all 3 sensors I still have the same issue. Tub is wired 220 and everything works but the heater?

  9. Hi there, Deivid,
    I will open up a help ticket for you and have one of my technicians reach out to assist.
    Thanks,
    Rebekah

  10. Hello good, I checked the relay board in the spa by disconnecting the heater power (P2 and P3) my reading gives me 120 volts but when I start the jacuzzi the voltage goes to zero. also the red HTR light goes off.

  11. Hi Bryan-
    I’m going to open up a help ticket for you and have one of my technicians get in touch regarding the issues you’re having.
    Thanks,
    Rebekah

  12. I had an issue where spa kept tripping breaker and burnt out gfci cord. I replaced cord, and drained and filled spa and everything worked fine except it wouldn’t heat. I used your method and checked the heater relay board and I’m getting no power at the heater terminals. So, like you said I replaced relay board. Problem not fixed. Still getting no power to heater terminals. I replaced with same exact p/n board and new one the “d10” light doesn’t come on and no power at terminals. I put the “old one” back in and have D9 and D10 lights but no power to the heater. I’m lost… haha mind you, the “old” relay board looks brand new and no burnt spots. Could I have gotten a bad board or could there be another issue I’m missing? Also, with “new” board no jets work or anything but everything works (besides the heater) with the “old” board.

  13. Hi there Paul-
    I’ve opened up a help ticket for you and one of my technicians will be contacting you shortly. His suggestion based on your comment is: If your jet pumps are both unplugged from the motherboard and the breaker is still tripping, you probably have a bad circulation pump, ozone or maybe even a bad breaker. Try unplugging one component at a time to see which component is causing the breaker to trip.
    You can reach our technical support depart via phone 805-541-9000, email: wizard@backyardplus.com or by text 833-607-3428 to continue troubleshooting.

    Thanks,
    Rebekah

  14. Hi Rebekah,

    I have a 2008 Vista Hotsprings that I recently drained and refilled. I was able to utilize the tub the next day and the jets gurgled for about 30 seconds then resumed normally. Two days later, I attempted to turn the jet pumps on and the GFCI breaker tripped immediately. I’ve isolated both jet pumps (removed wire terminals) from the control board and attempted to energize the jet function but it still trips the breaker. I’m assuming this may be a bad motor start relay. D17 blinks red just before the breaker trips. Any suggestions?

  15. Hi there, Bill-
    There are many reasons that a heater relay board can fail. I will open a help ticket for you and one of our technicians will help troubleshoot your issue.
    Thanks for reaching out.
    -Rebekah

  16. Thanks for the info. Very informative.

    I have a gen 1/2 relay board with a blown k2. Is there something to be looked into before replacing the board? That is, I would hate to order a new board, go through the replacement, and have the new board go the way of the old one without at least trying to find a root problem (if there is/are {a} common one{s}).

    I had the heater assembly and circulation pump replaced 6 years ago but it did not require board replacement. This was the initial fill of the season and I smelled smoke when I plugged in my 120 volts.

    Thx for any help you can provide/

  17. Hi there Brett-
    The testing instructions are located about halfway down on this blog. Look for the heading that reads: Testing 1st & 2nd Generation IQ 2020 Heater Relay Board (Invensys). Please let us know if you have any questions. Thanks!

  18. I think mine is a 1st or 2nd generation (no H1 or H2 terminsls) but I can’t find testing instructions for mine

  19. Hi there, Doug-
    If both the Green “D10” and Red “D9” LED’s are flashing, either the Wiring is incorrect, or you have a bad Relay Board. The “Green” “D10” LED should be either ON, or OFF. There is not a scenario for that LED to Flash. Verify you have the correct wires from the breaker to Terminals TB1 & TB3 on the spa. If “D10” LED still flashing, replace the board again.

    I will open up a help ticket for you and have one of our technicians contact you regarding your issue.

  20. I have a replacement 4th gen board (77119) for a 240V spa that has both the green and red LEDs flashing. It has not worked properly since it was replaced. What might cause this to occur? I do not want to replace it and ruin another relay board.

  21. Ready indicator blinking indicates a temperature sensor problem. Disconnect power for at least thirty seconds. If the blinking continues, call for 805-541-9000 service department for more troubleshooting advice.
    You can also test your thermistor by following the below directions:

    Thermistor Test Procedure
    1. Set the meter to 20K on the OHM scale.
    2. Record the temperature of the spa water.
    3. Unplug the thermistor from the control box.
    4. Meter across the two Thermistor leads.
    5. Refer to the Temperature versus Resistance chart below to find the correct resistance value for the temperature measured. If the temperature and resistance does not match that of the chart, this test has failed and the thermistor must be replaced. Remember if the spa has been inactive, the spa water temperature may be different than the water temperature in the heater housing.

    See item 79006 description for more information on the Resistance vs Temperature Graph

  22. I have a hot springs hot tub that has a flashing green light after about 10 seconds after you turn it on.i replaced flow switch and ozoneater put in new filters and refilled tub by center filter and still green light blinking.lots of air bubbles in center of tub…..??

  23. Hi there, Daron-
    I will open up a help ticket for you and have one of my technicians contact your.
    Thanks,
    Rebekah

  24. Hmmm, Ive just began on one I have and I see on here you are explaining things in a not very detailed manner. Basically if it has no voltage on parts usually doesnt mean to just replace the entire board on many items Ive worked on. That is the easy way. Might as well not spend time looking for probs. Right now by quick testing, the 220v line on mine is showing no power so the heater is not starting. Both green and red lights are on. Are you basically saying it is ‘flat out absolutely’ unrepairable or just saying to replace them to make it easier? There are other different questions I need to ask about so if you would like to assist me that would help.

  25. Hi Dean-
    Thanks for reaching out.
    The Heater Relay Board should be replaced. The fact that you have additional indicators, “LIM OK” and “CONTROL UNPLUGGED” both flashing indicate additional concerns with the Motherboard, and possibly the Control Head. I will open up a help ticket for you and have one of our technicians contact you. Please have your spa serial number handy.
    Thanks,
    Rebekah

  26. Hi Rebekah,
    After about 30 seconds after I power up, the red power light starts flashing and the circuit board starts clicking. On the circuit board the “LIM OK” and “Control Unplugged” also flash. The first inch or so of the white wire P2 has turned brown. The soldering on the back of the relay is slightly discolored – not as shinny as the the others, but not as burnt looking as I would have suspected. I’m wondering is this just a bad relay board or a bad heater or something all together different?
    Thanks,
    Dean
    +

  27. Hi, Ricky-
    It sounds like you may be having issues with your wireless control panel (remote). I will open a help ticket for you and have one of my technicians reach out.

  28. Tub will not turn on. Power to gfci verified, power to heater board model verified, power to main control module verified. Has a gen 4 heater module. Appears to be latest control board module. Removed and reinstalled remote battery. Reset breakers with approx. 15 minutes between off and on.

  29. Hi there, Holland-
    If the Green “D10” is not lit, the Heater Relay Board is not detecting the Incoming Voltage between Terminals TB-1 & TB3 on the Terminal Block. Check Voltage between TB1 & TB3, it should be 220V for the 220V spas. If no voltage present, Check the Sub-Panel for a tripped GFCI Breaker. Reset the Breakers. Still no Green “D10”, service required. Please contact our technical department and they can help you troubleshoot further. They can be reached via phone 805-541-9000, text 833-607-3428, or through our helpdesk.
    Thanks!
    Rebekah

  30. So when I checked my board my D10 green light wasn’t on when I got to step 4. Your walkthrough just says it should be on, but nothing about if it is off. Is that an indication the board has failed or something else?

  31. Hi Jason-
    Verify you have 220V between TB1 & TB3 on the Terminal Block. Then measure between the White & Black wires of the Heater Power Cord. If you only have 120V, the Relay Board needs to be replaced. If you have any other questions or want to troubleshoot further, please reach out via phone 805-541-9000, text 818-583-0350 or by help desk and our technicians will be happy to help you.
    Thanks!

  32. Hello. So I have a hot spring vista with 240 volts, and the multimeter is reading 120 volts when I check it across the white and black terminals on the heater board. You don’t have a answer to that scenario do ya? Thanks

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