I am a spa repair guy just starting out ( 200 in Chicago area called allsparepair.com
I have a helper who goes out, sometimes 50 miles to check the tubs for me. Occasionally, I have a problem that seems electronic, so I have him remove the spa guts and bring them to me so I can check the relays etc. My problem is that the sensors need to be hooked up in order for me to check the heat circuit and the various pumps and blower.
Are there one or two standard voltages, or resistances that make the temperature probe communicate with the motherboard and keypad. Here is an example:
I have an Elite Platinum, customer purchased at Costco with an intermittant heat problem. She says the heat works once in a while, but for the past few months the water has been cold most of the time.
I had my guy check the pressure switch and replace it in the field, but the results were inconclusive, so I had him remove the keypad and control box ( with heater) and bring it to me. I printed out the manual and checked the troubleshooting guide. I then hooked up the board on the bench and applied power. The keypad goes instantly to read " 32 degrees". This is because I do not have a temperature sensor hooked up. Can I install a resistor, or something into the temp probe socket temporarily to get it working so that I can test all the relays. My specific question today is how many ohms resistor do I need to get this board to think the water is around 90 degrees?

I have a similar problem with a Jacuzzi spa, but sent the board and keypad in to Horizon Spa parts for service. It will be 3 weeks before they can even look at it. With the right information and a few tips from more experienced tech's I may have been able to diagnose it on my bench myself and had it fixed already. So you see, my general idea is to set up a little testing station with 110/22o volts and various cords and things to be able to check these things out. Any advice from those that have already been down this road would be appreciated.