WMF Presto 1200S Error 166

Moin people...
I got a WMF Presto 1200S standing here from a buddy. I promised him I'd take a look and see what's going on. I've already repaired some coffee machines but the part is a number more complicated. But not insoluble, I hope!

Also, to the error. Error number 166 (according to operating instructions) ... Inlet steam boiler.
My acquaintance had told me however still another error message..namely error 88 = Boiler: Overtemperature.

Of course the thermostats are suspected. I don't know if they can be measured, though. Dismantled it and measured resistance. This is however in the cold state 0Ohm. Probably switched on as the temperature rises. But I can't check that because I don't know this value.

So long story short. I suspect either the thermostats or even the pump. Maybe someone knows the machine and can tell me if the pump has to start immediately after switching on. Because she doesn't. And therefore it can also happen that no water is pumped into the boiler at all. Which in the end would also explain the error to some extent.

Does anyone here possibly have an idea?

Would I like to hear your opinion.

Greetings and thanks in advance.
SteWo

No suspicion? Or do you need additional information?

Good evening,

"Boiler overtemperature": this may also be due to the power electronics. Doesn't have to be the thermostat. If the heating is no longer regulated correctly, the appliance will heat up until the temperature fuse burns out. The heating is usually provided by a larger triac attached to a heat sink. This one may be short-circuited. I've already had that at Bosch and Siemens.
So if you find a big triac, check it for short circuit with the ohmmeter.

Greeting HWS

Hello everyone
,I hope I can be helped with my problem.
Wmf Presto 1400 error 166 inlet steam boiler.
Have now replaced the water pump to the boiler. No success.
Flowmeter replaced on suspicion. Also no success.

Does anyone else have an idea?
Power arrives at the pump, so I exclude the power supply. (Here it would be certainly also another error code)Would be

nice if someone can give me a hint.

Thanks in advance!
Dominik

Hello,
No unfortunately I have not come further on the machine. Find einfsch not the error...
Or do you have meanwhile a solution

Greetings dominik

Check your steam pipe feeding steam boiler. They usually block up with descale.. 17mm 14mm and 10 mm spanners needed.