Overheating is caused by the delta being changed too high in the PID programming or PID sensors in the boiler being fouled up with limescale from hard water or oxidation from purified in as little as two weeks.
When a PID sensor fails from wire twisting, or electrical surge, or is not connected, the machine will not heat at all.
PID Reset (Mara PID PL62T)
With power OFF, you depress and hold the right button on the PID display, power on, and wait for the PrS to show on the screen, wait 10 secs, release, and then power off. Test the machine. If this works, this means someone went into programming and changed the delta settings in the PID menu.
Foul Sensor (Mara PID PL62T, Mara X)
If a foul sensor, usually if there is a coating of limescale or thin-film from oxidation (not always seen by the naked eye), it can not read the temperature properly, and the boiler overheats. The sensor would need to be removed and cleaned. When this sensor fails or is faulty, the machine does not heat at all.
Although there is NO PID display screen, there are 2 PID sensors. One is in the thermosyphon loop or the bottom of the heat exchanger and the other is on top of the boiler.
To clean the PID in the heat exchanger pipe, please remove the water softener and water from the reservoir, attach the hose properly to the internal base, and fill with a descaling solution, such as citric acid, white vinegar, or a light descaling solution. Run out 2-4 cups, turn off the machine, and let rest for 2 hours. Repeat once. Then rinse the water reservoir with water and repeat twice with water in the reservoir.
To clean the PID on the top of the boiler, cool down the machine, remove all steam by opening the steam wand valve, remove the reservoir, and then remove the screws on the top cover. Once the cover is removed, please look for the double red wire sensor. Disconnect the 2 pins black connector. Remove the larger nut with a crescent wrench.
MAKE SURE THE 2 RED WIRES NEVER TWIST OR GET PULLED OUT OF THE NUT AS THIS WILL DAMAGE THE SENSOR AND THE MACHINE WILL NOT HEAT AT ALL.
Wire brush the metal inside. There can be a film invisible to the naked eye. Once the film and/or discoloration is removed, please use 1-2 wraps of plumber’s tape on the threading and reinsert the PID sensor by hand. Use enough force but do not over-tighten. Connect the 2 pin connector. Re-insert the water reservoir filled with water. Test the machine.
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