Checking 3 Resistances Shorted to Ground, Fagor 1H-125 Oven

ID: 172148

Description:

Steps:

  1. Fagor 1H-125 oven with quite a few years of use; before it was thrown away due to multiple failures, it served me for creating this illustrative document.
  2. As we will see, the oven has 3 out of 4 resistances failed, a quite strange breakdown. Unless the thermostat is also broken, failing to cut off at the set temperature, and the resistances have failed due to excessive overheating.
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  3. Component identification:
  4. Yellow arrows: Top double resistance.
  5. Green arrows: Top turbine.
  6. Red arrow: Central turbine, "Turbo function".
  7. Blue arrow: Rear central resistance, for Turbo function.
  8. Orange arrows: Bottom resistance.
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  9. Checking the ohmic value of the dual resistance. What do we verify with this test? That the resistance heats up and is not open. Disconnect the Faston terminals so that the measurements are not skewed. The terminal on the left side with the blue wire is COMMON to both resistances.
  10. Inner or central resistance of the two: 37.9 ohms for an oven operating at 220 V European voltage.
  11. Outer resistance: 74.8 ohms for an oven operating at 220 V European voltage.
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  12. CHECK FOR GROUND FAULT between each pole of the resistance and the metal housing; this measurement SHOULD NOT GIVE US ANY VALUE; instead, we have a value in Kilo-ohms, so both resistances are grounded and DAMAGED.
  13. Photo 2, outer resistance grounded at 142.1 KOhms = 142,100 ohms; when if it were ok it would measure nothing.
  14. Photo 3, inner resistance grounded at 158.3 KOhms = 158,300 ohms; when if it were ok it would measure nothing.
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  15. Measuring between the common terminal of the 2 resistances and the metal casing, logically it also shows us an electrical leakage measurement value, CONFIRMED, DAMAGED.
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  16. Checking the bottom resistance, it also shows a reading of a ground fault and is also BROKEN; according to our measurements, it shows 3 different values due to the dirt that might be on the terminals. It SHOULD NOT SHOW A READING if it were OK.
  17. Why are there 3 grounded resistances in the same oven? It is an oven that was going to be thrown away, so I only dedicated myself to measuring the resistances for this document, but very possibly, apart from the 3 broken resistances, the oven may have a broken thermostat, as it does not cut off when it reaches a certain temperature.
  18. It continued to heat up, causing the resistances to fail due to overheating, otherwise, it is very rare to find 3 broken resistances in the same oven.
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  19. Illustrative photos; in this oven, the resistances are very simple to disassemble, coming out from the inside of the oven. They are only held by 2 screws each. NOTE: the upper resistance is attached to the thermostat bulb.
  20. Photo 1 upper gap.
  21. Photo 2 lower gap.
  22. In another document to be produced soon, I will show the resistances out of the oven and repeat the checks; for an initial check, it is not necessary to take them out of the oven, as you have seen.
  23. Supplementary video to the explanations and photos in this document:
  24. END of the Guide.
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