I inherited a HydroSpa that had been prefessionally installed 3 years ago. It has been empty and unused for the past 2 years. I filled the tub and flipped the switch. Everything works, pump - lights and blower but I get error codes of the 3 flashing lights under the temp reading in all phases of pump on or off. There is no heat either. I replaced the filters. I turned the screw on the pressure switch 3 or 4 times in both directions, no result. I do have a light on in the center of the circuit board which I think indicates my Hi Limit sensor may be bad. I have not checked continuity in the heater element but I think with the codes and light - it isn't the heater element.

Any suggestions? My pack is a Hydro-Quip model Z4H KXDL-34004EN. I already repaired an exploded water manifold - my local spa guy wanted to charge $900.00. I did it for $59.00 and about 2 hours. I would like to try and fix this myself.

Thanks in advance.