Dishwasher Mains Capacitor......... *BANG*

[Steve Walker]

Greetings -

Recently given a nearly-new Whirlpool dishwasher, surplus from a company's relocation. Installed it today, cleaned it out and ran it a few times to flush the pipes. Announced to adoring spouse that it's ready to use, and start putting my tools away. Moments later, there's a gunshot *bang* accompanied by familiar smell of "buggered electrics". Obviously someone up there has a sense of humour.....

Anyhow, tipped it over and immediately found the problem was a little grey device filtering the incoming mains, the casing had been blown open releasing a bit of black, oily muck. Photo at

device looks pretty similar to the replacement four-teminal capacitors pictured on , and I'm assuming that's what it is. However, it's mounted on a steel backplate with an earth connection into the capacitor.

Two questions for the experts please :

- Does this failure signify another fault somewhere in the dishwasher's circuits? I don't think it's meant to act as a safety cut-out, and I'm assuming it just chose to fail because of Sod's Law, but please correct me if I'm wrong.

- How do I spec an equivalent unit? Is it important to be very close to the original, or will any similar appliance capacitor serve the same purpose (suppresion of RFI / EMI?). The case is marked with following :

D.E.M F3CF75005L 0.15uF (X1) + 1M? +2x0.027uF (Y2)

250V 50/60Hz _ 16A/40?C

- Where would be the best place to obtain a replacement, preferably placing a web order today?

Thanks in advance! Steve

[Steve Walker]

Third line was typed with an Ohm symbol (horseshoe thing) at the end - not question mark. Ditto last line should be 40 deg C. Evidently the Windows character map doesn't get on too well with usenet.... :o)

[Andrew Gabriel]

Same has happened to me. I didn't know about it until I opened the dishwasher casing for another reason, and found the burned out remains of the thing. In my case, it was before the mains switch, powered all the time, and possibly did it when I was not in.

I wouldn't bother, unless you find the dishwasher interfering with the radio. Obviously, you must leave the connections to it safe.

[Roger R]

As you say it is a mains filter unit. These type of filter capacitors are called X and Y class or type. The X is between the line and neutral, and the Y's are one from each line to earth.

Your device spec above gives: X capacitor is of value 0.15 uF Y capcitors are 0.027 uF each.

In your example the capacitors are all in one unit, but they could be separate. For safety and ease of replacement its probably best to get a manufacturers spare from your local washing machine repair place.

Loads of info sites by entering 'Y class capicitors' in Google.

Roger R

[Steve Walker]

Thanks Roger -

The lowest-rated capacitor at the spares site (tinyurl in earlier post) are

4uF units, presumably a lot more 'suppresive' than the 0.20uF total rating of the failed unit. They're evidently 'heavy=-duty' enough to handle the current demand for a washing machine, so I'm guessing safety is covered.

Do you happen to know what might be the consequences of using such a replacement? I'm guessing that it would be either an increased or reduced effectiveness in suppressing RFI/EMI?

Or, for a bonus point..... Do you know anyone who sells single Y Class

0.20uF caps.... ?

[Frank Erskine]

A suppressor doesn't actually carry the washing machine's current - all it's doing is absorbing any RF produced by the machine. The actual value is chosen by the manufacturer to give the best effect.

Try to get somewhere near the original value and you won't go far wrong, but make sure that they're rated for at least 250V AC !

You'll likely get something suitable from a white goods repair emporium The machine will likely work without a suppressor, but don't leave it too long, because the suppressor also reduces sparking at the motor brushes and other switching contacts.

[Andrew Gabriel]

No, they are not suppressor capacitors, they are motor start/run capacitors, which isn't what you want.

Nearest I can quickly find is:

values of the capacitors aren't very critical. Voltage and current rating being sufficient is more important.

[Bob Eager]

I was about to suggest exactly this!

[Steve Walker]

Thanks both, very much appreciated (and thanks to Roger as well)

[Roger R]

As other posters have said, these are not the right thing at all, and quite unsuitable.

The Easy Fix shop doesn't appear to have a direct replacement item, though they do have some others under 'Washing Machine Mains Filter' these are probably going to be too awkward to fit.

could try looking for your part here: exact Whirlpool model to take this further, as you can't look up by part description.

As others have mentioned, the electronic component suppliers will have suitable individual X and Y capacitors, though probably not made up into an easily fitted 'plug in' replacement unit, and I would avoid fitting individual wire ended components in a washing machine where there is likely to be vibration and water about.

Roger R

[Andrew Gabriel]

CPC can also get you any Whirlpool spare part. You have to phone them though, as most of their white goods spares are not in their catalogue or on their website.

[Clive Mitchell]

In message , Steve Walker writes

R S Components, Maplin shitty-tronics (if they have anything in stock), Rapid Electronics, Farnell or indeed any good electronics supplier. You won't find 0.20uF caps, but you will find 220nF caps (0.22uF) They will have an AC voltage rating of either 250 or 275 volts.

There's a big difference between class X2 and class Y capacitors. X2 are for between live and neutral. Y are for live/neutral to earth where failure could cause a shock risk and tend to have very low values in the region of one or two nano Farad.

You can get complete filter modules that contain everything including series inductors and capacitors. These are rated by the load current.