Fix Your Stuff Community Store

Repair and disassembly guides and support for dish washing appliances.

761 Questions View all

Options

Miele Dishwasher Error F78 - Circulation Pump issue

I have a Miele Dishwasher G2872 SCVi. Lately, it has started to beep and shows “Technical Fault F78” on its display about 4-5 minutes into the wash cycle. Miele Tech Support say F78 means a fault with the circulation pump.

Did some initial checks - it looks like the water is draining out without problems and fresh water is coming in too. The filter is clean, and there appears to be no blockage in the circulation pump (I can move it easily by hand).

Any thoughts on what might be the issue? Is there any other remedy that one can think of (apart from buying a new dishwasher of course)?

Thanks.

Answer this question I have this problem too

Is this a good question?

Yes No
Score 5
7 Comments

Does it have any sensors to detect the water level?

by

Hi @asaxena ,

Are the spray arms turning?

Place both the arms in a known position and start the machine. When it has filled with water and"started to wash" open the door and check the position of the spray arms to see if they have moved at all.

If not then the pump is not operating.

Can you hear if the the pump motor is working or is it just humming?

by

@hootonberg Many thanks for looking at this. I don't know of any. I think the answer is no.

@jayeff Many thanks for your suggestion. Here is what I just did:

- filled up about 1 litre of water in the dishwasher, and put the arms in a known position. Turned it on, and heard the usual sounds that indicate water draining.

- about a minute later, I opened up the dishwasher mid-cycle. Initial water had all drained out. Shut it back again and let the cycle continue.

- About 2-3 minutes after this the dishwasher beeped to indicate the error F78. Opened it up - the dishwasher is now filled with water up to slightly below the filter handle.

- The arms were NOT in the position I left them in.

Looking forward to hear more. Thanks once again!

by

I have the same issue and now I have taken apart the dishwasher och removed the pump. The axle where the impeller sits is pretty sluggish to rotate on my pump. Does anyone know if this is normal or if the rotation should be really easy (like a normal ball bearing easy)? I'm thinking there could be an o-ring in place as a seal which, in that case, would make it more sluggish.

by

I wish I'd never bought this bloody dishwasher constant problems

by

Show 2 more comments

Add a comment

9 Answers

Filter by:
Most Helpful Newest Oldest
Most Helpful Answer

Options

Things that have worked for me with f78 error: once; took bottom spray arm off and poured hot (not boiling) water down hole, this cleared a blockage. Many times; drained machine and examined grill over channel at back, if this has anything at all in it, eg tiny hairs, clear plastic, eggshell, clean the channel. The grill can be removed by pulling the grey lever. The machine should then work. When the machine activates its pump it looks for a current down the channel at the back and shuts off with f78 if it doesn’t detect one. Small obstructions in the channel can obstruct the current and make the sensor think the pump is not working. This is a design flaw with this machine as the plastic grills over the channel are insufficient to stop things getting through them, and may make things worse because thin strips etc can drape over them and are then impossible for the machine to dislodge itself.

Update (04/30/2022)

the ( most frequent) problem which causes this fault in my machine is a blockage in the pump sensor channel. With the machine turned off and the racks, spray arms, filter etc, taken out, drain the broken machine as much as you can, using ladle or small container. You can see a channel covered with white grill bars at the back. This is the channel that takes the current of water from the pump to the sensor that tells the machine that the pump is working. Examine the channel carefully, you may need a torch. If you can see anything at all in this channel or draped over the white grill bars, then remove the grill by pulling the plastic lever and give it and the channel a good clean. Once the channel and grill are clear put the machine back together and restart it, the error should have cleared and the machine’s cycle should work without F78. In one case there was so much stuff in the machine that the channel kept on blocking, however running the machine with the grill cover off let it complete a cycle and it was fine after that.

The second most common problem, but much less often is a blockage. If you have checked the pump chamber and it is clear then try pouring hot (not boiling) water down the bottom spray arm hole, it should come out and fill up the bottom chamber. If the water backs up and then goes through in a rush you have cleared a blockage. Be aware that the water in the bottom of the machine will now be very hot.

If blockages in the sensor channel or elsewhere are happening it means that residue is getting though the machine’s filter. Make sure the filter and stainless steel mesh are clean, and there is no residue on the plastic where the stainless steel mesh sits which might be stopping it sitting flush against the bottom of the machine.

You may also want to clear very heavy residue off pots etc before putting them in the machine. My wife tells me I don’t do that very well, which is why we only ever get this error when I have stacked it.

Was this answer helpful?

Yes No
Score 5

1 Comment:

Thank you so much 😊Good suggestion 👍👍it helped.

by

Add a comment

Options

Usually the impeller comes apart in two pieces. The dishwasher detects low pump pressure, stops the wash, drains the water and ends the wash programme with F78 error.

You need to glue the pump impeller with special industrial adhesive and leave to set for 24 hours, you also need to take it apart, don't glue it in place. Made a video about it, search youtube for f78 miele impeller diy.

Miele wants 400eur for a new full pump, for older models there is a repair kit.

Was this answer helpful?

Yes No
Score 2
Add a comment

Options

I’d already thoroughly cleaned out the filter but was still getting the same error, until I tried MC Turnbull’s suggestion (1 tablespoon vegetable oil, 1L hot water, leave to soak for a few hours - I didn’t need anywhere near 24 hours). Fingers crossed it stays fixed!

Was this answer helpful?

Yes No
Score 1

1 Comment:

So pleased it worked for you too Rebecca. Ours had been unused for a number of months and perhaps went into overdrive on patience, lol!

Thanks everyone, great to help reduce global waste!

Mary-Clare

by

Add a comment

Options

I had the same problem, i saw this forum, i also tried with oil and boiling water, it didn't help, then i saw a german disassembling the Circulation Pump, i disassembled the machine, i removed the pump, i disassembled the pump, one of the sectors that is responsible for changing between the good water and the used one was with residues, which didn't seem normal to me, i cleaned everything, lubricated it, assembled it inside the machine, it started working, it wasn't easy at all.

It only worked once and again the same F78, again I disassembled the machine, before disassembling the pump, I noticed that there were bits of grease(or bits of anything) in the used water reservoir, I assembled the machine, heated the water, poured several liters of boiling water into the machine, waited a few minutes, unplugged it, plugged it back in and it started, I put it in the most powerful mode at 70ºC to see if that grease (or bits of anything) would come out of the reservoir, for now it works.

One of the things i was told to do when i bought the machine was to put the strongest mode with empty machine to work to clean the machine some times, I never did this, hence the possible malfunction.

The video of the German dismantling the pomp is here if anyone wants it.

Miele Geschirrspüler Umwälzpumpe zerlegen + Wasserweiche einstellen + F78 F79

https://youtu.be/yiuzdwnSaFM

Was this answer helpful?

Yes No
Score 1
Add a comment

Options

I had to do a hard power reset! Turn the power off for 30 sec min.

Was this answer helpful?

Yes No
Score 0

2 Comments:

That did not work for me.

by

Follow the advice in the video, but be patient! I cleaned everything as the video advises and removed the spray arm and poured into that hole about a tablespoon of vegetable oil then 1L hot water and left it 24-36 hours (I’d previously tried 15 mins without success). Ran the machine on the shortest cycle, it got halfway through.

Buoyed by this success, I repeated the oil and hot water and waited another day-and-a-half. It’s done the full cycle!

We’d been away so the machine wasn’t run for a number of weeks so the inverter had seized. It needs to switch between draining, filling and circulating a number of times throughout the cycle, so the oil helped to lubricate the sealed components.

by

Add a comment

Options

The main problem I had was defect impeller in the circulation pump. The upper part had loosened from the base. I glued it back on with epoxy, and the machine worked again for some months until it happened again. I glued it again, and it worked for some weeks. A better glue would have been better. But the real problem is (was?) the quality or method of attaching the two impeller parts together. Since the machine was 12 years old, the replacement punp would cost more than a new machine, so no a new machine is in place. (I also had a problem with the water supply (valve stuck in closed position with handle in open position), and with latch mechanisms in the circulation pump assembly stuck by the o-ring du to poor reassembly after I had opened it. Discovered and fixed.)

Was this answer helpful?

Yes No
Score 0

1 Comment:

See my reply below. A tech had tried to also glue mine in place, repair didn't last.

by

Add a comment

Options

I know everything says not to put boiling water in the sprayer arm hole, but that fixed 2 different Miele dishwashers that keep having this error when we return home from an extended vacation. I boiled it, then let it sit 30 sec before I squeezed Miele jet dry in then the near boiling water. Fixes it every time.

Was this answer helpful?

Yes No
Score 0
Add a comment

Options

In the sprayer hole I poured hot water after a tablespoon of vegetabilie oil then I used a balloon attached to the sprayer hole with air in it. Worked instantly. This was after maybe 20 unsuccessfully tries of hot water and restarting.

Was this answer helpful?

Yes No
Score 0
Add a comment

Options

I had the same issue and the technician advised me that my pump + the main computer controlling the pump both were gone. He was completely wrong, I opened the dishwasher and find that a small cockroach was inside the machine probably causing the sensor to report a fault. Cleaned the area and removed the insect, all working fine and it has been for now 2 months.

Was this answer helpful?

Yes No
Score 0
Add a comment

Add your answer

Abhishek Saxena will be eternally grateful.
View Statistics:

Past 24 Hours: 31

Past 7 Days: 186

Past 30 Days: 745

All Time: 84,027