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No Heat? How to Troubleshoot a Heater Relay Board in a Hot Spring and Tiger River Spa

No heat troubleshoot

Welcome to Backyardplus! In this post, we show you how to troubleshoot a heater relay board in a Hot Spring and Tiger River spa. Before we get started, let’s go over the tools and parts you will need.

Tools you will need:

  • Multimeter

Parts you will need:

  • 77119 Heater Relay Board 2001-2009.5
  • 77118 Heater Relay Board 2009.5 – 2012.5
  • 76858 Heater Relay Board 2012.5 – current

ATTENTION: If the red power light or green ready light is flashing on your control panel or the logo lights are flashing on your spa, it means you have a different issue going on. Please see our other videos and blog posts or call our tech support @ 805-541-9000.

Step 1. Remove the equipment door and the IQ2020 control box lid.

Step 1. Remove equipment door-
Step 1.1 Remove the IQ2020 lid-

Step 2. 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. Turn up the temp-

Step 3. Look at the diagnostic LED lights on the motherboard. The HTR ON light should be solid red and the LIM OK light should be solid green. If not, it means you have either a bad temp sensor, a bad control head or a bad control box. Please call our tech support for assistance @ 805-541-9000.

Step 3. LED lights-
Step 3.1 HTR ON and LIM OK-

Step 4. 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.

Step 4. Set multimeter-

Step 5. Check the incoming voltage to the heater on the terminal block. In 2001-2009.5 spas, if your spa is wired for 230 volts, you should have 230 volts between terminals 1 and 3. In spas wired for 115 volts, you should have 115 volts between terminals 2 and 4. In 2009.5 – current spas, if your spa is wired for 230 volts, you should have 230 volts between terminals 2 and 4. In spas wired for 115 volts, you should have 115 volts between terminals 5 and 7.

Step 5. check incoming power-

Step 6. Once you have established good voltage on your heater circuit, place one lead from your voltage meter onto the H1 terminal and the other lead onto the H2 terminal. It doesn’t matter which lead goes onto H1 and H2.

Step 6. Check power and H1 and H2-
Step 6.1 H1 and H2-

Step 7. If the HTR ON light is solid red, and you have good voltage coming into the terminal block, you should have 230 volts or 115 volts between H1 and H2 depending on how your spa is wired. If you have no voltage between H1 and H2, it means you have a bad heater relay board. If you have good voltage between H1 and H2, and your spa is not heating, it means you have a bad heater.

Step 7. Very good job-

Watch the video here! “No Heat? How to Troubleshoot a Heater Relay Board in a Hot Spring and Tiger River Spa”



Questions about your spa? Contact us! We are the top Hotspring spa parts retailer on the web.

Call us at (805)541-9000

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In addition to “No Heat? How to Troubleshoot a Heater Relay Board in a Hot Spring and Tiger River Spa” we offer:

  • Our Parts Finder which allows you to find exact-match replacements for your hot tub
  • Free technical support that will allow you to maintain and repair your own spa accordingly
  • Information regarding your products and their usage through our blog posts.
  • Tutorials and assistance through our videos
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Our goal here at Backyard Plus is to help save you money by avoiding costly service calls for repairs that you can easily do yourself!

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