Dimension 1 @Home Sojourn HP, 2003. Installed 2/2003. Initially they had to replace the dual-speed pump twice, but since then, no issues at all.

Symptom: 3 LED dots flashing. Temp. set point at 102, display shows 95, actual water temperature with thermometer = 98.

Water level fine. Both pumps circulate, pump 1 works on both speeds. Both pumps seem to flow very well, as they always have. No detectable low flow coming from jets.

Cleaned main filter, it was sort of gross with moldy slimy stuff on it. (Should clean more often...)
Removed filter, plunged the filter cavity with bathroom plunger, nothing came out of the waterlines.

Reset breaker, LEDs still flashing, same situation with the temperature set points and readings.

'Tested' the pressure switch, Len Gordon model (either 800125-3 or 800120-3 as far as I can tell) according to 'spababes.com' guidance: Power off, removed leads to the switch, power on, low pump on, ohm checked the switch leads and result was 0 ohms.

Model # on the control panel:

SC-MP-P122-P212-O1-CP1-NE-LS-H4.0-JJM-D13 10681-01A

When I opened the control panel cover, notable black dust on the center lower portion of the panel, like under or left of the pressure switch area. Please see attached picture.

Control panel is 'Gecko', 9911-500121 Rev C. The outer plastic casing has a hole in it, over the Pump1 button. Doesn't look like a seal integrity problem, but looks like a water or airbubble inside on top of the PCB. No visible corrosion, no visible rust.

Hopefully I provided all specs, and symptoms.

Any ideas, assistance, please let me know.
Thank you.

Dan.

System is 240 V.
I installed new pressure switch, same symptoms.

I checked ohms across the heating element, while detached from the PCB: 0 ohms.

Checked 3x fuses, all good.

Realized lots of black 'electrical soot' on the bottom of the blue plastic PCB controller pack. Also, the Zettler component just to the left of the pressure switch area is very blackened, lots of black crud on the circuit board under the Zettler component. Reference picture attached from 1st post. This main PCB is Gecko, 991-500117, Rev F. The Zettler component says A22150-1A-24DEF, 30A.

Any help from the experts out there?

Thanks again.

Dan.

Update from 10/21:
With the heat light indicator on, temperature set point higher than temperature reading on upper control panel, and pump 1 running at low speed, I checked if voltage was being applied to the heater terminals. Zero voltage was seen on the voltmeter. Also checked the new pressure switch installed, with heat light indicator on, pump 1 running at low speed, and no voltage reading at the pressure switch terminals.