Facts: Late 2003 Hot Springs Prodigy, 115 volt dedicated circuit, No-Fault PDR Titanium Heater (no reset button), IQ 2020 control, worked flawlessly for almost 6 years. Very careful with chemistry and filters.

Over a period of a few days it seemed to be getting hotter and hotter yet temp setting said 101 can't remember if ready light was on or off. Then it stopped heating, heat light on, ready light off and cooled over many days to ambient temp. Did a lot of reading here. Looked at heater board and it was indeed burnt up black from middle relay.

Purchased new Watkins/Invensys heater board. New style with new connectors. Excellent instructions, very clear on re-hooking wires, jumpers etc. Installed. Plugged back in, a few relay clicks, There are two tiny lights on the main board that are on, a green light (Lim OK) and below it a red light (Heater On).

No heat. Tested voltage between the two heater leads H1 and H2. When main pump is not running.....112 volts. When jets button pushed and pump running voltage drops to 0. My understanding is that this is how the 115 system works...heater or pump but not both at same time.

What is next? Thermistors at heater? One says limit and the other says control. How do I test these? I have a good multimeter.

Thanks

No, if there is voltage at the heater terminals, then the thermistors are satisfied. Are you sure it isn't heating? You're only going to get about 1 degree/hour at 115volts and the heater won't feel hot to the touch.

To make sure the heater is good, you can test continuity between the blk and white heater leads. Should get 9.8 ohms or so.

Thanks

I will test the resistance. Indeed, I was not patient. I simply started it back up, felt the heater pipes and said !%$#!

I'll test and give it over night to heat.

Patience is a virtue.......all is well...heating properly...thanks for the help.