Miele G5600 "Futura" Dishwasher Error Code F-24

[rp2813]

After researching on line, it appears the F-24 error code is an indication of a bad heater or a bad heater relay.  The relay seems to be the more common F-24 culprit.  I found a video that was very helpful, and the first advisory was to check the heater's resistance.  I did this using a multi-meter and got a reading of 12 ohms.  The machine in the video was located in Australia, so that means 240v.  I think the reading on that heater was in the upper 20's. 

 

Is it safe to assume that the reading I got would indicate the heater is OK, based on 110v?  If so, then the relay is likely bad, but the video didn't provide any way to test it.  Finding a replacement locally has been futile.  Even on line the hits I got were for used ones on eBay, and they were not cheap.  I hate handwashing dishes and they've been stacking up, so the sooner I figure this out, the better.

 

Any advice would be greatly appreciated.  Here's a picture of the relay:

 

 

 

[henene4]

12 Ohm is about spot on.
Checking that there is no fault to earth is important to, so for good measure, check between the heater and its casing, though that is unlikely as that would/should have caused more of an issue.

It could be the relay or the main control.
The main control sends 12V DC to the relay, which then switches the 120V AC for the heater.
If the control does not send 12V to the relay, that can't switch over.
Seems more like the relay is bad though, yeah.

Of course, where possible, you should always use original parts.
But that specific relay is actually mostly no longer available or obscenely expensive for a very simple relay.

If you are technical enough to do some wire splicing and terminating, you should be abled to just get any 12VDC relay that can switch 250V AC 16A and use that instead.

I would check the resistance between pins a and b on the relay to make sure the new relay isn't requiring to much more input current on the switching side.

If those are just regular spade connectors, you can get matching generic relays for just about 20$.
This one has spade connectors but might be a bit bigger size wise.
That's why you might have to rewire some stuff to fit it elsewhere:

https://www.mcmaster.com/product/69585K66

Control voltage would go on terminals 13&14 instead of a and b on that one, and the heater between one common and one normally open contact, so 5&9 or 8&12.

 

[brisnat81]

Have you just rung Miele to get a price on the part? Over here if you ring with the part number, or ring with the dishwasher model and ask for the heater control/relay, they should be able to email/text you parts diagrams that you can then use to identify the part and have them give you the correct part # and price.

Your logic in testing the element makes sense. The only other thing you could do is check whether there is voltage at the element terminals once the main wash starts and tries to heat. If there’s no voltage, it’s either the relay or the control board, but more likely the relay.

 

[gizmo]

You could open and clean the relay...

Normally they are replaced but I have cleaned a few relays before (mostly low voltage) and had luck. You need to be gentle with the old plastics to avoid breaking. I'd only bother if you have difficulty finding a new relay at a reasonable price.

Here's a Youtube on cleaning the relay... Not the best video but it gives you the idea.

 



 

Contact cleaner (from an electronic components store) is great for cleaning slightly burnt contacts.

 

Sometimes the relay contacts are burnt beyond repair, if the contacts are deeply pitted it must be replaced.

 

Also, try searching the part number "5870220 relay" on Google and you get matches all over the world. There seems to be plenty of used "tested" ones in Germany and the UK on Ebay for good prices. They are the <span style="text-decoration: underline;">same part</span> in 120V and 240V machines - the coil is 12 Volts DC and the contacts are rated at up to 16 Amps at 250 Volts. I can see them at Australian suppliers (where I am) for about AUD $170 which is about USD$115, plus postage.

 

 

[me]

Relays failure is typically from stuck contacts caused by arcing, measure the resistance (or check for continuity) between the switch contacts 13 - 14, and also 23 - 24, those should be open circuit when the relay isn't powered.

If they are stuck then a few gentle taps with a screwdriver will typically be enough to temporarily free them. Removing the relay may have jarred it enough to break the "weld".

Sooner or later, possibly even next use the relay will weld again because the plating on the contact surface is damaged, so may be unwise to use it if they have this fault.

 

[rp2813]

Thanks to all for the good information.

 

I opened up the relay housing and as you can see in the shot below, there's been some serious arcing action happening.  The contacts had what appeared to be pitting, but on closer examination there seemed to be a texture to the silvery surface on the contact points.  Without a brand new relay for comparison, I don't know if the textured surface is intentional or not. 

 

I think the carbon residue inside the housing is enough to indicate trouble regardless, so I'll begin the hunt for a replacement relay.  I'd prefer brand new, but may have to settle for used & tested.  I didn't think my dishwasher was so old that parts for it could be NLA by this time.  It's been doing a great job, so I'll happily pay for a relay as opposed to a whole new machine.

 

[me]

You would expect to get arcing since it is switching a few amps.

A quick web search suggests that error can also be caused by a faulty pressure switch. See video

If the relay contacts weren't stuck closed when you checked it, then I would be inclined to check the coil isn't open circuit and fit it back in the machine to see if the error has gone away, which would confirm the relay is the issue, and also allow you to use the machine until it sticks again.

 

[me]

I'm not sure about the wisdom of wedging a screwdriver in the sensor to test it as shown in that video, it might puncture the rubber gasket. I'd either blow in it, or use something blunt.

 

[henene4]

I don't think F24 could be the pressure switch.
As far as I am aware - I might be wrong - if the pressure switch senses a low level it sends a signal to the control.
I don't think the heater is switched through the pressure switch.
Though somebody on here not to long ago had his pressure switch fail on a G6000 machine. Only way he noticed was that his usage readings were through the roof.

F24 says that there is a fault in the heating circuit.
If this specific machine switches the heater through the pressure switch, then yeah.
If there has been arcing - and the signs are there on that cover - that can lead to bad contacts.
I've been watching HVACR videos' channel on YT and having pitted contactors from arcing causing bad or no connection is pretty common.

Looking at Mieles parts catalogue, this machine was on sale from 2010-2016.

Miele has the relay in stock for 83,51$.

 

[henene4]

Safest way to make sure you're getting the right part

https://www4.miele.de/msd/MSD#/start

Enter the M-Nr. from the rating plate, that includes any revision specifc things your specific machine has.

What's interesting is that this machine lists a lot of 240V parts?
Did Miele do the same for these machines as with their washers where they just threw in a transformer?

Cause 12 Ohms at 120V works out just right, 12 Ohms at 240V is like way to low.
But then again, if that was the case, your fuse would have certainly blown in your distribution panel.

 

[rp2813]

Henrik, thanks for the argument against the pressure switch.  I located the switch and was dreading the process of accessing and extracting it.  Melvin was right about the pressure switch video not being the best presentation, so I wasn't comfortable with pursuing that possibility.

 

Unfortunately, the relay isn't available on line from the Miele parts site you provided.  I've had no luck getting through the Miele USA parts site, so I've made an offer on a relay listed on eBay with the only seller who will accept returns. 

 

If my machine was produced in 2010, I guess 13 years is a decent run for a relay.  If it was among the last produced in 2016, not so much. 

 

[henene4]

Maybe I'm looking at the wrong version or - even though I have the US specifically selected - that site is wonky.
The parts catalog is pretty new, so it might just still look for IP location and override the location selection.

But I still get it displayed as available.
But if you found something for a reasonable price, the better.

Also finally found a list of all common Miele DW fault codes.

F24 is described as a heater circuit issue.
F25 is described as a failure to reach target temp.
F26 is described as a overheat fault.

So if the pressure switch would keep interrupting heating the DW would time out and probably record F25.

There is a specific fault for the pressure switch, analogue to the washers, F51.
Don't know what would trigger that.

 

[me]

Found this manual

TECHNICAL INFORMATIONG 5xxx Futura Dishwashers(All US Models) https://www.manualslib.com/manual/1333124/Miele-G-4205.html#manual

F24 -> https://www.manualslib.com/manual/1333124/Miele-G-4205.html?page=137#manual

 

[me]

Looks like the same wiring arrangement as in that video

B1/13 in that diagram is the pressure switch

also see p86

https://www.manualslib.com/manual/1333124/Miele-G-4205.html?page=86#manual

 

[brisnat81]

Hi Ralph,

Have you actually tried calling Miele, in AU, the only way to get parts as an end user is to call. Those relays have been used in the washers and dishwashers for a very long time, if that specific part wasn’t available, there would be a substitution.

Cheers

Nathan

 

[henene4]

I totally forgot that document existed

Must have read this 1000 times and never connected the 2 dots.
Thanks for picking up on that!

The whole relay/pressure switch setup is very interesting.
The pressure switch does communicate with the control but switches the heater on both poles at the same time.
The heater relay also switches both poles.
So I was wrong, the pressure switch does indeed physically switch the heater.

However, F24 does certainly indicate a relay or wiring issue.
The machine does check the heater relay at certain points in the cycle.
That can happen when there is no water in the machine.

The machine then checks that with the pressure switch open and no power to the relay, no voltage goes to the electronic control.
If there however IS voltage, the machine registers F24.

The condition of the pressure switch is tested before that test takes place.

The pressure switch errors are actually connected to that self check routine.

F51 is the pressure switch error.
A few seconds before F24 is checked, F51 is checked.
For that, the machine DOES send voltage to the heater relay.
Since there is no water in the machine, the machine DOES want to see voltage at the control since that means the relay is closed and the pressure switch is open.

If the pressure switch did not indicate correct water levels during actual cycle operation, either a water intake error F14 or pressure switch error F52 would be displayed.

Given that info and the picture of the relay, I would assume the contacts are sticky.

It's a really weird, but very safe and pretty smart setup.
This way, to get unrequested heating, both the pressure switch AND the relay would have to fail closed at the same time.
The pressure switch is more likely to fail open, while the relay is more likely to fail closed.

 

[me]

Yeah, I agree, I think the only way I can see a faulty pressure switch causing a F24 error is if water leaked into it providing a path to earth, then there might be enough potential from the earth connection to trigger the F24 fault when the heater relay was tested while open.

At miele's silly prices for a cheap relay, I think I'd measure the current that relay coil draws on a 12V DC supply as it is important not to exceed that, and find a suitable replacement to wire up, which probably wouldn't cost more than 2-3 quid + postage. Would need to be safely secured and insulated of cause.

 

[rp2813]

Thanks for further confirmation that the relay is likely the source of the F24.  This information matches what I found on line:  the most common cause of the F24 code is a bad relay.

 

I searched for Miele parts dealers in the San Francisco bay area and got lots of hits, but when I called few of them I was told that they don't stock Miele parts.  Go figure.  It seems that the only way to purchase a Miele part is to schedule a service call through an authorized Miele service provider.  My offer for the used relay was accepted.  Although the price was higher than a new one from Miele, it's still a lot less expensive than the additional cost of sending a repair tech out.

 

This situation has spooked me about ever buying another Miele product, I will tell you that much.

 

[brisnat81]

Here is the part available from Miele USA. Added to my basket and ready to checkout.

Item 120 in the 8th diagram

MSD

www4.miele.de