I just got this hot tub from a friend. It has been sitting for about 2 years with out being used. After replacing many of the tubes, gaskets and couplings I thought I had it ready to go. However, My heater does not come on at all. The LED light on the display does not even come on. I cannot find the hi limit switch that I've read about and I would prefer to try and fix it myself - if possible.
Thank you in advance for any help you may be able to offer.

Relevant info: (I hope)
1. 1996 Marquis Mirage

2. Main Power Input: 220, 230 or 240 volts- not sure which. We got the "higher powered" hook up. As you probably can guess, I don't know much about electrical work. A pro did the electrical installation for me.

3. Type and/or Brand & Model of Control:
Unknown, it's a silver box

4. Electronic topside control

5. Pump Configuration (Examples):
1 Main pump 230V, 1 Waterway Circulation Pump


6. Thermostat: No idea where it is

7. Heater Type:
Electric 2 1/2" Stainless Flow Thru, 15"(or so) long

I believe you have a digital display? If not, this might not be your answer. If so, the heat and over limit are controled by the circuit board. Check to see if the pressure switch is functioning. It will be attached to the flow-through heater tube. You can rule this out by taking the two wires off it and shorting them together. If you have heat, you found the problem. Either the circulation pump is not operating, or not enough.... or your switch is defective. If you still don't have heat after shorting out the switch wires, then make sure all the electrical plugs in the silver box are on their respective places and tight. If that is all good, you may have a bad temp sensor, but I would really start to suspect the control board itself.