Welcome to Backyardplus! In this post, we show you how to troubleshoot the red D9 and green D10 light on the 77119 heater relay board. Before we get started, let’s go over the tools and parts you will need.
Tools you will need:
- Phillips head screwdriver
- Small flathead screwdriver
- Multimeter
Parts you will need:
- 77119 Heater Relay Board
- 77087 Motherboard
- 73225 Control Head
Step 1. Remove the equipment door, and the IQ 2020 control box lid.
Step 2. Turn the temperature up higher than that of the spa water. Make sure the HTR ON light is solid red on the motherboard.
Step 3. The 77119 heater relay board has two diagnostic LED lights up at the top, just to the right of the cylinder shaped aluminum capacitor, D9 and D10. Under normal operation, the D9 light should be solid red, and the d10 should be solid green on the heater relay board.
Step 4. If the red D9 light is flashing, it is an automatic failure of the heater board. The 77119 heater relay board must be replaced.
Step 5. If the red D9 light is flashing on the replacement heater relay board, you must replace the 77119 heater relay board, 77087 motherboard, and 73225 control head at the same time.
Step 6. If the spa is not heating and the green D10 light fails to come on, check the incoming voltage on the heater circuit and the voltage going to the heater at H1 and H2. If you have no voltage going to the heater and no green D10 light, it is an automatic failure of the 73225 control head. The 73225 control head must be replaced.
Watch the video here! “How to Troubleshoot D9 and D10 Lights on the 77119 Heater Relay Board: 01-09 Hot Spring Tiger River”
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