Gas stove issues

[Roymachine]

Has anyone had issues with the gas stove?

Our right side burner won't t stay on unless you are holding down the control knob.

Mercedes Benz Bristol say it maybe leisure battery related, but I doubt it. Reading the VW California forum it seems more likely to be a faulty thermocouple.

They are replacing the battery under warranty anyway as it is not holdong charge, so we will see!

Has anyone had similar problems with the hob, or experience of MB gas related knowledge?

 

[Ian]

I had this exact problem. It is a faulty thermocouple on that ring. Mercedes replaced this under warranty and it now works fine. Nothing to do with the battery.

 

[Roymachine]

Thanks, useful confirmation - I'll let the dealership know

 

[Roymachine]

I had this exact problem. It is a faulty thermocouple on that ring. Mercedes replaced this under warranty and it now works fine. Nothing to do with the battery.

Out of interest which Mercedes dealer was it that replaced the thermocouple?

 

[Ian]

Cheltenham and Gloucester.

 

[PhilipHa]

The thermocouples on both hobs my Marco Polo's have been playing up on and off for a couple of years. The hob lights but doesn't stay on. Sometimes if you hold the knob down for several minutes it eventually stays on, sometimes not. Having done some research on the web re VW campervan Dometic hobs and talking to a mobile caravan mechanic it transpires that the thermocouple when hot produces a very small voltage which is enough to hold the gas valve open. However it doesn't take too much additional resistance on the cabling from the thermocouple to the gas valve for it to stop working. An alternative to replacing the thermocouple and associated wiring is to move the wire connection back and forwards on both the hob end and gas valve end, causing friction which cleans up the contacts, reduces the resistance and the hob stays alight.

At the hob end this involves removing the top rings on the hob - easy, and then gently turning the thermocouple in a circular motion back and forwards. At the valve end, you need to remove the drawer below, then the metal plate (4 screws), and then twist the 2 cables around back and forwards as they go into the valve (pictures below).

This photo is the 2 valves from below, the 2 cables (brown, yellow) go into the green plug which you rotate gently back and forwards.

This is the same plug with the brown and yellow cables which from the side, the cables go between this control valve and the underside of the hob/thermocouple, which you twist back and forwards:

And this is the model number of my hob - can be used to find the Mercedes parts diagram which is a little confusing:


I am not sure this is a permanent fix but it is working for me for the moment. The low voltage from the thermocouple, its sensitivity to small additional resistance from corrosion makes sense, and perhaps you may not need to replace the thermocouple if you have the same problem? I suspect on mine the additional resistance was mainly at the thermocouple/hob end, so there was probably no need to remove the metal plate below the hob.