(1) Heater Inspection

ⓐ The heater consist of heater terminals (-A1) and (-A2). They
  comprise one heater while heater terminals (-B1) and (-B2)
  also comprise a heater. Use the tester to inspect for possible
  broken wires or any short-circuits.
ⓑ The heater's measured resistance value is between 3Ω~15Ω
  depending on volume, and the short circuit measure between
  the case and heater terminal must be greater than 1MΩ.
ⓒ Sensor tube (-C) is the over-heating control sensor.

(2) Heater Replacement

ⓐ Turn off the power and discharge until the steam pressure
  reaches zero.
ⓑ Completely discharge all water inside the steam generation
  tank.
ⓒ Disassemble the wires connected to the heater terminal after
  marking them.
ⓓ Unscrew all the bolts (-D) on the heater plate.
ⓔ Remove the shorted or problematic heater.
ⓕ If there is damage to the heater plate packing (-F), remove
  and replace with a new one. <The packing should be done
  with 3mm thick, high temperature-grade red spider.>
ⓖ Scrape off any scale build-up inside, and remove any scale
  on the surface of the heater.
ⓗ Re-fasten the heater plate, reconnect all wires, and turn the
  heater on.