Dometic AES fridge/freezer RM7655L

[Clive Beeza]

When running on gas fridge light (gas) will work fine most of the time
but will then for unknown reason flicker, and the burner and pilot flame have gone out
if I turn the power selector control to off position for a few seconds,
and then re-select gas, and puff the flame relights and all is well until the next time,
have changed the gas valve, the flame burner, and jet, plus the relay,
all to no avail
The concern is if we are out for the day in summer
and it knocks off all the food contents could be ruined
so I need to fix the issue permanently
Any funsters come across this type of fault

 

[Branston]

When running on gas fridge light (gas) will work fine most of the time
but will then for unknown reason flicker, and the burner and pilot flame have gone out
if I turn the power selector control to off position for a few seconds,
and then re-select gas, and puff the flame relights and all is well until the next time,
have changed the gas valve, the flame burner, and jet, plus the relay,
all to no avail
The concern is if we are out for the day in summer
and it knocks off all the food contents could be ruined
so I need to fix the issue permanently
Any funsters come across this type of fault

Have you swept the chimney flue?

 

[Sleeveless]

Sounds like it could possibly be excessive resistance in the thermocouple circuit to ground , this is a known Dometic issue on some models and there is a service bulletin issued . The action of turning the selector off & on slightly improves the contact surfaces temporarily . The current running in this circuit is extremely low, measured in mA , this current is generated solely by the thermocouple. If the current is insufficient the gas safety solenoid will drop out and the valve will close. This is also more likely to happen on the lower of the two flame settings.

 

[Clive Beeza]

Have you swept the chimney flue?

Yes flue is spotlessly clean

 

[Clive Beeza]

Sounds like it could possibly be excessive resistance in the thermocouple circuit to ground , this is a known Dometic issue on some models and there is a service bulletin issued . The action of turning the selector off & on slightly improves the contact surfaces temporarily . The current running in this circuit is extremely low, measured in mA , this current is generated solely by the thermocouple. If the current is insufficient the gas safety solenoid will drop out and the valve will close. This is also more likely to happen on the lower of the two flame settings.

how do I get hold of the service bulleting you mention

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[TheTwoOfUs]

I have exactly the same problem and have all the parts you mention replaced by a Dometic service engineer and it still persists. I would be interested in seeing a service bulletin for this as well.

 

[Sleeveless]

Apologies , so many versions of this fridge ! With AES, the troublesome MES switch is replaced by a burner control module and the gas valve (GV100) is controlled by that. Although the same high resistance rule applies to the thermocouple connections, both to ground and to the control unit , also check the gas valve to ground, connections circled red below. Worth checking that the gas valve is getting a steady 1.5 volts from the control unit though . For anyone without AES , the bulletin is Dometic, "Flame does not keep burning" Publication-No.: 599 5183-07 en/Service 2003.10.16 BO/KV, for AES models the text below from Dometic is relevant. The burner control device ignites the flame when gas mode is chosen and supervises the ignition(safety time for ignition approx. 30 sec.). The recognition of the burning flame and its supervising is carried out with an ionisation electrode within the gas burner (flame failure device). To ensure good ground contacts an additional cable is mounted on the burner chassis.The gas valve GV100 is controlled by the burner control device

 

[Jabstatt]

I had ongoing issues and changed every component in the fridge control system, modules, burner, gas valve, thermocouple etc.

One day in desperation I removed the plug from the control box and cleaned all the pins.
Magic!
Never another issue!

Tony