Heating element fault
So i'm troubleshooting this washing machine. the problem is that it has started to burn the fuse (10 A automatic fuse is installation).
It runs fine at first during the prewash, but when it goes to the main wash the fuse goes instantly. So my thought was the heating element has burned out. i tried running at washing program cold, that way the heating element is not active, and the machine finished the program without problem.
Then i opened the machine up to measure the resistance thought the heating element. i disconnected to two wires from the terminals and measured 27,6 ohm. i thought the web for a reference and found a video that clams the heating element usually should measure between 20 and 50 ohm.
the heating element is rated to 1900W at 230 V AC, so i calulated the required resistance with ohm's law R=U^2/P. the result is 27.8 ohm, exactly what my measurement was.
I tried to run the program (60 degres celsius) with the heating element disconnected, but with the wires connected to my multimeter. nothing measured during prewash, but is measured 230 V during main wash and the fuse was okay. So the wiring is okay
So my question is: Is it the heating element that is the reason to my fuse blowing, or is it something else?
The washing machine is the only thing connected to the set of fuses that blows
I took out the heating element and it is covered in i took out the heating element and it is covered in calcium, picture attached
Solution Summary
AI-generated from this discussion
This thread was marked as solved. Here's a summary of the problem and the fix, generated from the discussion below.
Washing machine tripped the supply during heated wash due to faulty heater
- The problem
- The washing machine completed prewash and cold programmes, but the 10A installation fuse tripped instantly when the main wash began and the heater should have been energised. Resistance across the removed heater terminals measured 27.6 ohms, which appeared normal for a 1900W, 230V element. The removed heater was heavily coated in limescale.
- Likely cause
- A heating element leaking to earth under load was the strongly supported diagnosis. The forum advice noted that a normal resistance reading on a multimeter does not rule this out, and that an insulation test meter is normally needed to confirm leakage to earth.
- What fixed it
- The recommended action was to replace the heating element. The original poster later confirmed that after fitting a new heating element the machine worked properly again.
- Checks to try
- Cold wash completed without fault
- Fuse tripped instantly on main wash/heating stage
- Heater resistance measured 27.6 ohms with wires disconnected
- 230V was measured to the heater circuit during main wash with the element disconnected
- Heating element was removed and found heavily covered in limescale
- Parts or tools mentioned
- Replacement heating element
- Multimeter
Safety: Further diagnosis should be carried out by a suitably qualified appliance engineer.
10 Answers
Hello Nicky. I hope you don't mind, I tidied up your post a little to make it easier to read. I found it awkward to read easily all in italics. I've also embedded the photo for you. Yes I think you are probably right. If it only trips the electrics when you use a wash cycle that has the heating element running then it is very likely indeed to be faulty heating element. You wouldn't normally be able to see anything wrong with such an element unless by any chance it was extremely badly corroded and had come apart.
The fault can only be detected normally by an insulation test meter which puts 500 V DC through the element and traces any leakage to earth. Your picture shows a lot of limescale etc. which is actually quite common after some years unless the washing machine has been used with the correct amount of detergent to protect it. This is rarely the case as most people seem to skimp very much on washing detergent (Limescale in washing machines and how to prevent it)
So regarding the blowing the fuse you can't normally detect that with a multimeter. You need a proper insulation tester as described in my article on the subject which you should find interesting to read Washing Machine Tripping or Fusing Electrics
Need Professional Help or Spare Parts?
Thank you Andy, i'm grateful. I will swap out the heating element with a new one.
Good day to you.
Thanks Nicki. Let us know how you get on. As I said before, the only way to be hundred percent sure they element is causing the fusing is with a meter that you don't have. However, the symptoms very strongly implicate the heating element.
Need Professional Help or Spare Parts?
I finally got the heating element replace and the machine is now working fine.
Nice one. Thanks for the update.
Need Professional Help or Spare Parts?
Hi - new to forums! I have a Bosch washer dryer but the dryer is not working. I have put a multi meter on the element tags and there is no continuity. Similar test on sensors show continuity. However voltage to the heating element is showing as circa 68v whereas to the sensors it is 180v. Is it normal for the element to be provided with a lower voltage? Any advice gratefully received.
If the dryer isn’t heating and the element is open circuit you’d normally expect a replacement element to fix the fault. I never check voltage, only components.
Need Professional Help or Spare Parts?
Thank you Andy - I am going to get a new element and fingers crossed it will fix the problem. I decided to check voltage in case there was another fault and then found the low voltage which seemed odd.
Hello there. In all of my 30 odd years as an engineer I never checked the voltage anywhere. We were always taught to diagnose faults by checking that voltage was present, but never the level of voltage as such. All are testing was done with the washing machine unplugged using a continuity test meter is to test that power was running through to specific parts and then what the resistance was through those parts.
Need Professional Help or Spare Parts?
That’s interesting. Those that don’t know (!) have all suggested that I check voltage as well. I have a new element on order and when it’s fitted I will post if it all works alright.
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