Thetford N4000 fridge & gas taps

We usually stay on sites with EHU and have not needed the fridge or heater to be operated from gas. This year we shall be staying on non EHU pitches so decided I would check the fridge/heater operation on gas. Neither worked and after some checking I realised the two isolation gas taps were marked incorrectly, the fridge tap isolated the heater and heater tap isolated the fridge. Both appliances then worked correctly.

Thought I would check to see what would happen if I turned off the gas taps whilst the appliances were running. Heater stopped instantly and showed an error code …. which was what I expected.
Fridge (presumably) stopped running (it’s too quiet for me to hear) but the display was unchanged, indicating the fridge was running normally. I would have expected to see some indication of malfunction. Is this a fault …. gas tap ‘does’ isolate the fridge as it will not start with tap in the OFF position.

Handbook suggests display should show error code 3 if gas valve is shut.

Reading the small print in the manual it states the fridge will not run on gas for 15 mins after driving for safety reasons …. didn’t realise this.

Peter M

I find the display flashes if the fridge loses its source of power.  So if set to auto and the gas tap is shut, it will flash on arrival at a pitch until connected to an EHU.  If the gas tap is open, it won't flash as the fridge will take its power from the gas.  If the fridge is set to gas and then the fridge is turned off, it retains its gas setting when turned back on and if the gas tap is shut, it will flash.  The flashing may not happen instantaneously.

Thanks Caraman …. shows that more investigation is needed. Shall start with a ‘reset’ and see what happens.  Peter M

Did a ‘hard reset’ of fridge ie turned off the EHU then removed battery fuse. Left fridge without power for a few minutes then reconnected ….. all seems to be operating normally now. Thanks for your response Caraman. Peter M

The fridge will continue to run on gas after the valve has been isolated, as it burns the gas left in the pipe. If the valve isn’t adjacent to the fridge then it may carry on for several minutes after isolating. This is what we’re finding on the XL, where the valve is a metre or so of pipe run from the fridge. On the 6m Kemerton the valve was next to the fridge so not such a delay.

Conversely, when you come to select gas operation the next time there will be a similar delay before gas gets to the fridge and ignition occurs.

To avoid all this we de-select gas operation on the fridge panel before isolating the valve. The sequence is reversed when selecting gas operation, ie turn on the valve before selecting gas on the panel. Sounds a faff but this sequence soon becomes familiar … that said, Mrs k-b is in charge of it, which is much more reliable!

A further point is that we never use the automatic setting for the fuel source. If you’re on EHU and the supply is interrupted then the fridge will automatically select gas. If this happens overnight or while out for the day you could find your lpg tank has emptied. We speak from experience!

Tim

Some good points above but we do use Auto on an EHU but with the gas tap closed.  This allows the fridge to continue running when we disconnect from the EHU and drive.  We only open the gas tap to run the fridge on gas by exception when we are on a pitch with no EHU or a metered EHU.

Whilst I appreciate K-B's point about the effect of an unexpected interruption of power when fridge is on Automatic, nevertheless we leave the fridge on Auto, with gas tap open, simply because of the convenience: if we stop to park - whether briefly for a bite to eat or parking for the afternoon - I don't have to think about the fridge: it looks after itself. It will, about 15 minutes after stopping, switch to gas; I start and drive away, and it switches back to 12v; I reach a site and connect to EHU mains, and it runs on mains. 

If there's mains electricity available, it'll chose that first; if no mains but a 12v supply, it'll chose that as second; and if there's neither source of electricity, it'll chose gas. If on gas, and it detects electricity, it'll switch to that in place of gas.

It's only drained the LPG tank once: came home, didn't connect to usual EHU until a week later..... gas gone.

Cymro

Cymro wrote:...

It's only drained the LPG tank once: came home, didn't connect to usual EHU until a week later..... gas gone.

Cymro

I had a similar experience after out first service when they left the fridge gas tap on.  I got home and didn't realise the fridge was on. In those days when at home I didn't always shutdown the EC700 as I do now and I wasn't connected to an EHU so the fridge remained on for a couple of weeks burning gas.  As a result we unexpectedly ran out of gas on our subsequent trip.  This is partly why I don't turn the gas tap on unless I definitely want to use gas.  This was important on our last two CL trips in Jan & Feb when we were on a metered EHU and I wanted to run the fridge on gas as it was cheaper.  Had I left it on Auto it would have defaulted to mains.