Welcome to Backyardplus! No lights on motherboard and topside control panel? In this post, we show you how to test the heater relay board in a Hot Spring Spa when this happens. Before we get started, let’s go over the tools you will need.
Tools you will need:
- Phillips head screwdriver
- Needle nose pliers
Step 1. Remove the equipment door and IQ 2020 control box lid.
Step 2. Make sure the GFI breaker is turned on.
Step 3. Set your multimeter to 200 volts A/C for 120 volts spas.
Step 4. On the terminal block, place one lead just above where the black wire goes in and the other lead just above where the white wire goes in. You should get a reading of 115-120 volts. If you have no reading, make sure you have a fresh battery in your multimeter and make sure the main circuit breaker is on.
We have good voltage!
Step 5. Once you have a good voltage reading, disconnect power from the spa.
Step 6. Disconnect the black (P4 or J5), and white (P7 or J4) jumper wires from the heater relay board. The jumper wires supply voltage to the motherboard.
Step 7. Reconnect power to the spa.
Step 8. Place the two leads on the black and white jumper terminals. You should get a reading of 115-120 volts. If you have no voltage reading, it means you have a bad heater relay board. In this case, we have no voltage going to the motherboard which means the heater relay board must be replaced.
(NOTE): If you have a good voltage reading between the black and white jumpers, it means you have a good heater relay board. It also means you have a bad jumper wire or a bad motherboard and topside control panel. To diagnose a bad motherboard and control panel, read part 2 of this blog series entitled, “How to Troubleshoot a Dead Motherboard and Control Panel.”
Watch the video here! No Lights on Motherboard and Topside Control Panel? How to Test the Heater Relay Board in a Hot Spring Spa
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