Moin, I built in my 80s ne thermo top T. The naturally not working properly – used heating olé. Symptoms: After about 2:50 minutes (pronounced ~170 seconds +/- 10) the heating goes off, while it goes up into full load operation. I type that the flame monitor is gone. One hears the flame breathe and it comes hot exhaust gas out of the exhaust when the heating breaks off the operation and restarts. At the time you feel then also like the water sc humming evenly warm up. Had the nose full and removed the thing once. At room temperature the flame monitor c.a 3.7 ohm. I hold my handy pocket gas burner that the tip of the pin starts to glow does something happen on the display of my multimeter… Satte 7,4ohm! Can this be? 3,7 ohm cold and 7,4 hot? Does it seem to me a lot less for a PTC resistance. Thought it would rather go into the kiloohm area if it gets well heated. res? OBD interface is ordered, heating is read out as soon as I have the adapter.. But think that there is only the flame monitor gone. Greetings