Thetford N90 Premium EES gas problem (1 Viewer)

[Noblescort]

Hi,

In need of a bit of help. Our fridge runs fine on 240V & 12V but has developed a problem when running on gas. It fires up as it should and runs fine for about an hour or so, then randomly the burner goes out. The light on the LCD display flashes and error code 9There is plenty of gas and the burner was cleaned recently. The flame is nice and blue. If I tun the fridge off and back on again, the same scenario is repeated. I suspected thermocouple, but I cant see one anywhere. I seem to recall someone once told me the thermocouple might be incorporated into the ignitor. Anyone got any suggestions as to what might be going on (wrong)? Thanks

 

[Stealaway]

Will this help?

N90 PREMIUM BACK - Leisure Spares

THETFORD N90 PREMIUM FRIDGE SPARES

www.leisurespares.co.uk

 

[Noblescort]

Will this help?

N90 PREMIUM BACK - Leisure Spares

THETFORD N90 PREMIUM FRIDGE SPARES

www.leisurespares.co.uk

Thanks. I've had another close look at the fridge and it looks exactly like that diagram (ie no seperate thermocouple).

Now just need to determine why it's doing what its doing. Any suggestions?

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[jockaneezer]

Item number 7 in that exploded view looks like a thermocouple ?

 

[ambulancekidd]

Certainly sounds like a thermocouple on its way out, not expensive or difficult to replace.

 

[Noblescort]

Item number 7 in that exploded view looks like a thermocouple ?

I've been doing more research and now understand that item 7 is the ignitor, which also acts as a heat sensor but not in the traditional thermocouple way; it uses direct spark ignition and flame rectification which detects electrical current flowing from the electrode through the flame to the burner casing (earth). When the flame fails, the current stops and the gas valve is closed.

I've just been doing some more investigation on the motorhome and discovered another interesting symptom. With the fridge running on gas, if I start the engine, everything is fine. When I turn off the engine, about a second or so later the gas valve shuts the gas off. Done this a dozen or so times now and always does it.

Would the ignitor/thermo thingy cause this or is it more likely the PCB?

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[Stealaway]

It sounds like the slight increase in voltage with the engine running is having an effect. What is your battery voltage?

 

[jockaneezer]

@Nobelscort I think sometimes when running the fridge on gas with the engine runnig, when you switch the engine off, the system thinks you may be filling up with fuel at a petrol station, so knocks the fridge gas off as a safety precaution ?

 

[Noblescort]

@Nobelscort I think sometimes when running the fridge on gas with the engine runnig, when you switch the engine off, the system thinks you may be filling up with fuel at a petrol station, so knocks the fridge gas off as a safety precaution ?

That would make perfect sense! - I'll ignore that (non-fault) then.

Still leaves me with the issue that the fridge keeps turning itself off randomly on gas though.

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[jockaneezer]

Our gas hob has those flame detection devices which sense a micro voltage (unlike a traditional thermocouple that expands internally and pushes a switch) and two of them wouldn't stay lit when you stopped pressing the knob. I pulled the Lucar terminals off where they connected to the knobs and gave them a scrub with a glass fibre pen to improve the contact and they've been fine ever since. Can you try that on your burner ?