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Re: Bosch SMS4472GB sticking in the wash cycle
Alright, after a couple of good washes I can now say that the issue is solved.
Machine washes fine and quickly.
I would have liked to drop a bit the washing temperature to 55C but I could only find a 65C spare thermostat.
What puzzles me is the two 85C cutoff thermostats. They are cycling several times during the wash..I suppose its normal tho.
Hopefully the recycled thermostat I put should run for quite some more time and provide good service for the coming years..
Thanks to everybody for the help in solving this.Re: Bosch SMS4472GB sticking in the wash cycle
Of course I thank you Martin! Without you I wouldn’t have even found the thermostat! Writing of the phone is always a problem… Something gets corrected or vanishes! Thank you all for your hell p
Re: Bosch SMS4472GB sticking in the wash cycle
alright
the problem is now solved.
new/old 65C and new/old 85C thermostat solved the problem.
The machine has 2 85C thermostats, one of them was tripping at 50C. I opened and gave a look, the contacts were completely blued and badly burnt…Now the machine is back in shape.Re: Bosch SMS4472GB sticking in the wash cycle
Hello
I already ordered the 65C stat..its taking a while to get here..
In the meanwhile I disassembled the old thermostat (65C) and the contacts are completely covered by a black gunk. No doubt it did not make any contact even after tripping.
I scraped out the black gunk and now contacts are clean, but I will anyway wait for all the spares before putting things back together.Re: Bosch SMS4472GB sticking in the wash cycle
I had a test run yesterday.
The logic is clear.
The machine washes with cold water till it reaches the brush symbol. At that time the timer is disabled and the heater turns on.
Once the temperature reaches 65C the thermostat clicks and the timer moves, immediately the power to the heater is cut.
At this point, it doesnt matter the thermostat opens again because the timer proceed by itself.
It goes this way till it reaches the rinsing cycle, close to the sun symbol the timer stops again, heater goes on, and it waits till the thermostat closes. Immediately the heater goes off and timer restarts (even if the thermostat opens again the heater doesn’t come on again and the timer doesnt stop).
Then the heater goes on when the drying cycle starts.Unfortunately the thermostat I have got is rather unreliable, sometime clicks and closes, sometime just clicks but there is no power to the timer..I guess over time the contacts have sparked out as there is no capacitor between them…will see how it goes with the new one.
Regarding the other thermostats, they do not have “proper” contact with the element, and for what I see they should be 85C cutoff thermostats. The element is certainly running hotter than 85C as it boils water on contact!Re: Bosch SMS4472GB sticking in the wash cycle
Then I guess without the thermostat the program runs too quick and there is no enough time to warm up the water…as a result dishes dont come out really clean.
When drying them up, probably the same thermostat hangs the program till the 65C are sensed..without it, it goes too quick and doesnt dry them properly..
I managed to fix the thermostat, or at least appears to be fixed. The contacts were oxidised, i gave a clean with a toothpick and some contact cleaner, on the tester it works and I can trigger it by suspending on top of a glass of boiling water.
I just need to have a try to see how it does in the machine…Re: Bosch SMS4472GB sticking in the wash cycle
Does this dishwasher have two heaters? the coil on the bottom heats up nicely…Is there any other “heater” for the water?
Re: Bosch SMS4472GB sticking in the wash cycle
I noticed..
Without it it doesn’t wash good at all and doesn’t dry at the end..
I guess the heater doesn’t go on much.. If at all… Hope to get the spare soonRe: Bosch SMS4472GB sticking in the wash cycle
I ordered one anyway
I found a website that sold it at a reasonable price and put on the order..On ebay I could find only at 40£, this website sold for 2£!
Same identical…Re: Bosch SMS4472GB sticking in the wash cycle
Ok problem identified and solved.
By following the wiring I found that the step motor was wired to a white cable, and in that particular part of the cycle (where the machine stopped) was not getting any power.
The white cable was going underneath to a sensor, shorting the sensor caused the step motor to resume the cycle.
I removed the sensor and it fell apart in pieces.
Its a mechanical thermostat, with a bimetallic strip and an aluminium housing. The housing was all distorted probably by approx 20 years of service, so the thermostat was not closing anymore at 65°C.
Joining the wires together fixed the problem, now the water is still hot but the machine doesnt hang anymore in the washing cycle.
I looked online for the spare, but it costs too much and the machine works perfectly without so i’ll leave as it is.Re: Bosch SMS4472GB sticking in the wash cycle
looks like im gonna have a nice nightmare 😀
I guess that the wiring harness is not available as a spare anymore…Re: Bosch SMS4472GB sticking in the wash cycle
true
but how does it explains that sometime it works (on some progs) and sometime doesnt?
might be the wire “half” broken and sometime touching sometime not?Re: Bosch SMS4472GB sticking in the wash cycle
Hello Martin and thanks
I have noticed that it happens only on program 3, program 4 works fine (I did not try program 2).
I will double check again the wiring harness, it really looks fine but it might be a cable broken inside (in that case it will be hard to figure out as they are sleeved in a gray plastic)
