Siemens Dishwasher SN278I01TG/04 Not heating

[Taff543489]

This dishwasher displays the error code for not heating. I ran the diagnostic program which confirmed the problem. The Wash pump works fine, and the heater gives a reading of 19 ohms. I swapped the control module with another known serviceable module. The same fault occurs. The reading on the heater is what I would normally expect. If its not the module or the heater or the cabling to the heater is there anything else I have missed. The readings on the thermostat on the heat pump are the same readings obtained from a new pump. Any prods in the right direction would be appreciated

[electrofix]

are you sure about the heater ohm reading
using ohms law I = V/R gives 230/19 give heater current of 12 amps
am assuming your meter is a bit out
either way if you have a reading it cant be the heater
to be honest as far as I know you have covered both eventualities. Also on the heater are 2 ntc’s which I assume you have also checked. there are 2 relays that have to close to make the heater operate but have no tech to understand why yours are not. What I do not know is how the machine determines water flow to switch on the heater. Have you looked at the water height when its full ?

Dave

[Taff543489]

Yes water height appears fine about 15mm above the filter assy. There is another item plugged into the sump with a couple of wires. I’m not sure what it is or what it does. This machine is one of the top of the range all singing and dancing with interior lights. I do get a reading on the ohms meter so would assume its serviceable. I wonder if this is what determines the water pressure to switch the heater on as you suggested! I might just fit a new one to rule it out.

[Taff543489]

Both the module and the heat pump changed. I ran the diagnostic program and E31 error displayed. I contacted Siemens Tech desk who stated that the fault was on the drying side. This machine has a metal container located just behind the module with an element and a fan which I believe drys the load. I don’t see how this would affect the wash cycle which has no heat? I will need to check the resistance on the drying element which should be 27-28 ohms.

[Kentish]

This sounds like a zeolite model. The zeolite gets flooded and then fails to help heat the water on wash/dry. The early ones were modified to help reduce water into the zeolite. I’m no appliance care engineer, but had my own Siemens dishwasher do this twice in 2 years.
The first time App Care replaced all the zeolite components, the second time the dishwasher went to scrap.
It is not a cheap repair.

[Author]

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