Dishwasher controller - Page 1
Forum section: electronics / repair

author: Simon
author_rank: Unknown
timestamp: March 01, 2020, 05:34:18 pm
content: This is not a repair as such but I want to reverse engineer the connections to the controller in my indesit ICD661 dishwasher so that I can run my own wash programs on my own controller controlling the various bits of the dishwasher

author: shakalnokturn
author_rank: Super Contributor
timestamp: March 02, 2020, 10:22:18 pm
content: http://servicenet.indesitcompany.com/data/img_sm/sm46741.pdfAlthough I understand the point in wanting to do that, an Indesit seem like a poor mechanical base to build your own electronics onto...

author: Simon
author_rank: Unknown
timestamp: March 03, 2020, 07:36:24 am
content: Well at the moment it takes too long to wash and it's what i have. I don't care for the drying cycle that requires salt that now is being gobbled up by the machines and left dirtily on everything it "washes" so time to hack it.The is a box in the base with a PCB in it and cables from every device in the machine so should be fairly easy to just take control of each device.I just want to run as hot as i can for 10-20 minutes and done. None of this running at 50-70 for 2 hours. Industrial machines do it and don't need detergent.

author: floobydust
author_rank: Super Contributor
timestamp: March 03, 2020, 08:53:11 am
content: Writing your own dishwasher firmware is a little hairy, there is safety to think about with leaving a heater or fill solenoid on. You have to filter and debounce all inputs, and have timeouts if a switch or float gets stuck, pump doesn't work, that kind of thing. But nothing an Arduino couldn't pull offThe controller board looks straightforward, I would see if it's possible to read the dishwasher MCU's firmware and disassemble it.Just need to post PC board pics and sketch a schematic to assign I/O, the MCU seems to have only 16 pins.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: March 03, 2020, 09:08:11 am
content: Drop your insurance a line and let them know you are running your own dishwasher firmware... I'm sure they will be interested!Make sure you use a Watchdog timer and try and fail safe!

author: Simon
author_rank: Unknown
timestamp: March 03, 2020, 11:02:26 am
content: Quote from: NivagSwerdna on March 03, 2020, 09:08:11 amThe whole point is that i can do a wash in 20 minutes or less while I am there rather than the current 23-3 hours which means I have to put it on a timer when I am not there. As for safety I am fast loosing confidence in everything. i recently found that my dehumidifier was intermittent due to a loose wire. I opened the plug up to find that one screw was not even screwed in and that the wire had just been sitting there making poor contact. But it's OK it has a CE mark and everything!Yes i would do my best to make it as safe as possible. Things like over temperature protection can be done with an external comparator that can cut out the heater.

author: Simon
author_rank: Unknown
timestamp: March 03, 2020, 11:04:01 am
content: Quote from: floobydust on March 03, 2020, 08:53:11 amThanks, that's very handy. Saves me a lot of reverse engineering.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: March 03, 2020, 11:43:20 am
content: According tohttps://www.quora.com/What-OS-is-used-in-dishwashersthere is an implication that at least one approach is FreeRTOS based... that would seem a good choice... perhaps something STM32 Nucleo or maybe a TI CC3200 LaunchPad might be a good choice of platform rather than squishing into an Arduino.Sounds like a fun project. You could start by logging the activity of the existing unit to get an idea for what it gets up to.Update over the air or at least WiFi connectivity would stop you having to disassemble your kitchen all the time.Have fun!

author: Simon
author_rank: Unknown
timestamp: March 03, 2020, 11:53:32 am
content: I just want to turn it into and industrial type. Fast and hot - no detergent required. I have used one before at a venue which is what prompted the purchase but this was a bit of a disappointment as it takes hours and does not always wash well.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: March 03, 2020, 11:58:42 am
content: Quote from: Simon on March 03, 2020, 11:53:32 amI blame the EU.

author: Simon
author_rank: Unknown
timestamp: March 03, 2020, 12:12:42 pm
content: Quote from: NivagSwerdna on March 03, 2020, 11:58:42 amDon't be silly. I do not know why it has been done this way when other machines are faster and probably use less power. I'm sure that 20 minutes at 90C is less power than 2 hours at 60C. Maybe indesit did this to stop the machine being used professionally as it takes too long so that you have to buy a more expensive "professional" machine.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: March 03, 2020, 12:14:39 pm
content: Quote from: Simon on March 03, 2020, 12:12:42 pmWater consumption is a key criteria I believe. So sloshing less for longer...https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=uriserv:OJ.L_.2019.315.01.0267.01.ENG&toc=OJ:L:2019:315:TOC

author: Simon
author_rank: Unknown
timestamp: March 03, 2020, 12:22:17 pm
content: I would use the same amount. Long hot wash to get it all off, short hot wash to rinse it off.

author: tunk
author_rank: Super Contributor
timestamp: March 03, 2020, 12:23:55 pm
content: Maybe it's cheaper to design it to run at 60C rather than 90C?If that's the case, it may not last long if run at 90C, and youmay risk some of the plastics breaking and cause a leak.

author: Simon
author_rank: Unknown
timestamp: March 03, 2020, 12:26:38 pm
content: Quote from: tunk on March 03, 2020, 12:23:55 pmI'm willing to take the risk. It goes to 70C tops, you would hope that in the name of safety everything is to withstand 100C. At 90C water is effectively boiling already so might have to be a bit less.

author: tunk
author_rank: Super Contributor
timestamp: March 03, 2020, 12:48:51 pm
content: I don't have a clue about dishwashers, but there might be otherdifferences: higher pump/water pressure and faster heating inthe commercial versions.Do you know what kind of temperature sensor it has? If it's anNTC/PTC you may be able to fool it with a resistor in series orparallel. It that works, run it for 20min and see if that cleansyour dishes. If so, put it on a timer for 20min.

author: Simon
author_rank: Unknown
timestamp: March 03, 2020, 01:15:00 pm
content: Quote from: tunk on March 03, 2020, 12:48:51 pmThat's a very good idea as t has a 30 minute light cycle at 40C, if I can make that 80-88C i will be happy for a start and see if it works.

author: tunk
author_rank: Super Contributor
timestamp: March 03, 2020, 01:26:08 pm
content: Another thing you may bear in mind: Heatup time.Looks like a dishwasher uses about 0.5-1kWh. If you assume allis used for heating (not true) and have a 2kW element, heatingwill take around 15-30 minutes (probably even more to reach80-88C). Modifying the light cycle has a potential risk:If you accidently put it in a higher temperature cycle, yourisk overheating/boiling.Edit: It may have a mechanical thermostat as a safety to preventtoo high temperature. I suggest that you open the dishwasher tofind out what you have.

author: madires
author_rank: Super Contributor
timestamp: March 03, 2020, 01:36:06 pm
content: I'd assume that you would have to spend a lot of time to experiment with timing, temperature and so on to get the best washing result.

author: SilverSolder
author_rank: Super Contributor
timestamp: March 03, 2020, 01:51:48 pm
content: Professional dishwashing detergents often contain phosphates... which is the real "secret" to making even ordinary household dishwashers perform well.

author: Simon
author_rank: Unknown
timestamp: March 03, 2020, 02:42:23 pm
content: Quote from: tunk on March 03, 2020, 01:26:08 pmNo if you fool the thermistor it will simply read a different temperature. Once it gets to the new higher temperature it will stop. Only a few liters is used at a time so heating time should not be too long but this is the reason a completely new controller is actually probably safer.

author: tunk
author_rank: Super Contributor
timestamp: March 03, 2020, 04:01:33 pm
content: I guess it depends on the sensor. If it's an NTC sensor and you fool itto 85C in the 40C cycle, then it will never stop heating if you use the70C cycle.E.g. a 10k NTC:40C 5.33k70C 1.75k85C 1.07kI.e. to fool the 40C cycle you have to use a ~4.3k resistor in series.In the 70C cycle you will then never reach 1.75k - it will never stopheating (apart from the safety thermostat).

author: Simon
author_rank: Unknown
timestamp: March 03, 2020, 04:09:56 pm
content: Yes true

author: shakalnokturn
author_rank: Super Contributor
timestamp: March 03, 2020, 07:56:18 pm
content: Quote from: tunk on March 03, 2020, 01:26:08 pmThe service manual / power schematic shows there is one.There may be a little time to spend on sniffing communications to the front panel off that is on a serial bus. Maybe not considering the number of pins on the interconnect.

author: Simon
author_rank: Unknown
timestamp: March 03, 2020, 08:23:36 pm
content: There are unless i miscounted as many wires as there are buttons/switch positions/led,s on the front but I may have missed some so yes it could be that there is some comms but the control would all be in the main ECU i think.Would the overflaw switch be what is used to tell if it is full? I see a flow meter but not sure if that is water in or circulation water to aid diagnostics.

author: floobydust
author_rank: Super Contributor
timestamp: March 03, 2020, 09:21:42 pm
content: It seems to use a flowmeter to measure the water fill, and has extra safety switches. If you've been filling for 20 minutes or see the overfill float switch trip, then there is trouble. If you didn't fill at all leave the heater off, kind of thing.Flow Meter"Located in the rear of the base between the inlet water valve and air break, the flow meter controls the quantity of water entering the machine. As water passes through the flow meter, a signal on every rotation is counted by the module, which switches the water valve off, when the correct amount of water has entered the machine."Pressure Switch"The Pressure Switch controls the overall volume of water in the tub and signals to the module when the heater can be turned on. If the pressure switch is not in the full position, the heater will not be energised."Heater Pressure Sensor"Attached to the heater is a safety device protecting the heating element. When the wash motor starts, the pressure sensor is closed by water pressure, this signals the module to switch the heater on. Minimum operating pressure is 1 Bar. In the event of the wash pump not starting, the module would not switch the heater on (water pressure below 1 Bar)."Anti-Flood Device"Consisting of a polystyrene float and micro switch. Leaking water into the base panel operates the float switch, which when made, sends a signal to the module, aborting the cycle, bringing on the drain pump and displaying a fault code."

author: Simon
author_rank: Unknown
timestamp: March 03, 2020, 10:00:45 pm
content: Bollocks, I'd have to read the flow meter then unless that pressure switch can be taken as a full signal to stop the water fill and start the cycle.

author: shakalnokturn
author_rank: Super Contributor
timestamp: March 03, 2020, 10:49:45 pm
content: Usually flow meters are nothing more than a magnet on a vane in the water inlet switching a reed outside.Control board programming will throw either a "too much pressure" or "too little pressure / no water inlet" error if the reed switch count is out of limits for a normal water fill time bracket.

author: Simon
author_rank: Unknown
timestamp: March 05, 2020, 08:09:19 am
content: Maybe if the thermistor does not have a disconnect detection I can just unplug it and let the thermal protection hold the hottest temperature. I'll have to have a play with a thermometer probe in there during a run.

author: tunk
author_rank: Super Contributor
timestamp: March 05, 2020, 12:16:33 pm
content: It may be better to replace it with e.g. a 10k resistor(assuming it's a dumb controller not checking that theresistance is declining). Also check the temperaturerating of the "thermostat", and it may possibly not bea thermostat, but a thermal fuse.

author: Simon
author_rank: Unknown
timestamp: March 05, 2020, 08:28:49 pm
content: I unplugged the sensor and it only went as high as 55C on a 40C wash so I expect it has a calculation for how much energy is needed to increase the water from an average cold temperature to a not dangerous one.

author: Simon
author_rank: Unknown
timestamp: June 20, 2020, 08:29:02 pm
content: Well this piece of crap has now failed. When it tries to open the detergent flap it blows the RCD is the house. Disconnecting the solenoid does not solve this so either anther component is energized at the same time that is faulty or there is a problem with the controller board. It pumps water around no problem.

author: SilverSolder
author_rank: Super Contributor
timestamp: June 20, 2020, 10:11:07 pm
content: Is an entire replacement board cheap? Sometimes available used on the bay of E's.

author: Simon
author_rank: Unknown
timestamp: June 21, 2020, 08:20:37 am
content: I am thinking of DIYing it. If the overflow switch trips before I have too much water I can use that to shut the inlet valve and start a cycle.

author: madires
author_rank: Super Contributor
timestamp: June 21, 2020, 09:55:29 am
content: Nicked wire?

author: Simon
author_rank: Unknown
timestamp: June 21, 2020, 10:06:44 am
content: No idea, all seems good and the wiring has high impedance to earth and the solenoid is not shorted.

author: SilverSolder
author_rank: Super Contributor
timestamp: June 21, 2020, 11:42:12 am
content: Taking a step back, I don't think changing the machine cycle times will improve the cleaning performance.Ever since phosphates in detergents was banned, dishwashers (and clothes washers) have done a pretty poor job...

author: Simon
author_rank: Unknown
timestamp: June 21, 2020, 12:48:42 pm
content: that is why I want to control it and run it hotter if the thermal cutout will allow. I once use a machine that went to 90C and cleaned in 20 minutes, none of this 50C for 2 hours bollocks.

author: SilverSolder
author_rank: Super Contributor
timestamp: June 21, 2020, 08:43:15 pm
content: Quote from: Simon on June 21, 2020, 12:48:42 pmHave you tried to get hold of proper dishwashing detergent with phosphates? (It is still legal for professional use in commercial kitchens / restaurants, at least in the USA)It solved all my problems...

author: Simon
author_rank: Unknown
timestamp: June 21, 2020, 09:25:42 pm
content: But you don't need detergent if you just make it hot enough.

author: SilverSolder
author_rank: Super Contributor
timestamp: June 21, 2020, 09:34:55 pm
content: Is detergent free dishwashing a "thing"? It's been a while since I've worked in a commercial kitchen...

author: Simon
author_rank: Unknown
timestamp: June 22, 2020, 06:21:16 am
content: No idea but my sister had a party in a village hall where we were to wash up ourselves. The dishwasher ran for 15-20 minutes at a time and got quite hot, we were not putting detergent in, so unless it had a tank somewhere.

author: BradC
author_rank: Super Contributor
timestamp: June 22, 2020, 07:33:13 am
content: Quote from: Simon on June 22, 2020, 06:21:16 amEvery kitchen I worked in (as an actual dishwasher) had a detergent bottle hooked up to the back of the "dishwasher".Yes, they ran fast and hot, but the only ones I've ever seen without detergent were "glass washers" behind the bar. Not saying they don't exist, but I never worked with one.I think you'll need to move far more water than your feeble domestic is capable of to get anywhere near the cleaning speed of a commercial unit. It's not just the temperature but pressure used to move the dirt. Domestics tend to use caustics to saponify the fats to assist in washing them off. Commercials use a bit of detergent and blast it away.

author: Simon
author_rank: Unknown
timestamp: June 22, 2020, 07:35:46 am
content: Well I can still throw the usual tablet in.

author: Simon
author_rank: Unknown
timestamp: June 22, 2020, 07:42:31 am
content: Maybe I need to buy a decent machine but all the home ones take forever and are generally crap.

author: Simon
author_rank: Unknown
timestamp: June 22, 2020, 01:30:55 pm
content: https://ao.com/product/sn236i03mg-siemens-iq300-standard-dishwasher-silver-67561-23.aspxthis one claims to have a 26 minute cycle, it's bigger than the garbage from indesit/hotpoint so may well work quicker if not filled right up and water can get round easily.

author: SilverSolder
author_rank: Super Contributor
timestamp: June 22, 2020, 02:00:42 pm
content: Quote from: Simon on June 22, 2020, 07:35:46 amI've been down this road too, even bought a new dishwasher because I got so tired of dinghy looking results... it didn't help.The modern tablets / detergents simply don't work well... they are neutered without the phosphate.I found a commercial product that works - it was a night to day experience, and I never looked back. Shiny clean glass and dishes every time, without super hot water or anything.

author: Simon
author_rank: Unknown
timestamp: June 22, 2020, 02:16:59 pm
content: so what did you buy? I don't think my old one was very good anyway. the salt thing gave up some months ago with it using all the salt I put in in one go and leaving me with salty dishes there was so much. So generally it's a piece of shit. I can't remember how long I have had it, I think 2 years, absolutely crap so anything else may well just work better.

author: SilverSolder
author_rank: Super Contributor
timestamp: June 22, 2020, 02:44:26 pm
content: I ended up with a Philips/Whirlpool... just what was on special at the local appliance shop. Middle of the range.My family in the UK still have an AEG dishwasher from 1990, and also an AEG washing machine from the same time, both still work flawlessly and have never been serviced!

author: jc101
author_rank: Frequent Contributor
timestamp: June 22, 2020, 04:55:54 pm
content: I have an integrated slimline Miele dishwasher, which has worked faultlessly for the last 10 years or so. What I have noticed is some brands of dishwasher tablets don't always fully dissolve on the eco 40c wash cycle. This programme doesn't take long to run through at all, 40 mins or so from memory. The normal sensor wash takes quite a time, but that doesn't bother me. The eco wash beeps when it's done, but keeps the fans going for drying, so the longer I can stand the beeps the dryer everything is when I open the door.Cost a packet to buy, but so far been worth every penny. I think it's still got a factory warranty until end of next year, I added a 10 year parts and labor policy from Miele when I got it, that added 10 years onto the initial 3 year warranty. Assuming all keeps working at the end of the warranty period it will have cost about £90 a year overall.The previous one, from Smeg, lasted just about 5 years. It was repaired several times during that period. Several sensors, pumps, and logic boards. I gave up with it in the end, as it was a pain to keep taking out when it needed fixing.

author: Simon
author_rank: Unknown
timestamp: July 12, 2020, 10:35:50 am
content: The assholes only want £145 for a replacement controller for a machine that cost £199. i was going to give the old one to my sister but yep, 4 years on, more e-waste

author: madires
author_rank: Super Contributor
timestamp: July 12, 2020, 10:57:53 am
content: I wonder when we'll see inexpensive dishwashers with DRMed detergent tabs. Just like ink jet printers.

author: SilverSolder
author_rank: Super Contributor
timestamp: July 12, 2020, 12:00:45 pm
content: Quote from: madires on July 12, 2020, 10:57:53 amSpeaking of that, it looks like the printer makers are making amends - I saw some models recently that come with big, refillable ink tanks - and the printers were more expensive to make up for it. I'd probably go with one of those rather than adding tanks to an existing model, if I was a heavy ink user!

author: SilverSolder
author_rank: Super Contributor
timestamp: July 12, 2020, 12:04:17 pm
content: Quote from: jc101 on June 22, 2020, 04:55:54 pmModern phosphate free detergents simply don't work... I use commercial detergents (which are still allowed to have phosphates) so you can make do with a lot less detergent, and everything comes out sparkling clean, every time! Before anyone freaks out about the environment: you can fully legally buy phosphates at DIY stores to wash your walls or outside decks, for example before repainting. Just one of those wash-jobs will likely release more phosphates into the environment than 10 years of using a dishwasher...

author: Simon
author_rank: Unknown
timestamp: July 12, 2020, 12:39:28 pm
content: My new one cleans ok but still takes a long time, the fastest sensible run is the intensive at 70C but I can leave it on eco at night if it works, just doing my first eco run now.