Nuevo Fridge Question

by Tincataylor Mon May 19, 2014 7:57 am

The fridge has worked perfectly up to now but I think I may have upset it by having it running on hook up while parked in my fairly steep drive overnight in order to get it well cool for a function the following day. It was running OK when I first hooked it up but by the morning it had switched itself off and the fringe was warm.

I parked it on the level and changed over to gas and it ran perfectly. However when I changed it to battery prior to setting off to the function the "battery" LED did not light and I don't think it was working, but again worked perfectly on gas when we arrived at the function. It also now functions perfectly again on the mains hook up when parked on the level.

I have checked the two fuses that say they are for the fringe and both of those look OK and I get a "fuse blown" warning on the control panel if I yank them out.

Any ideas how I restore its function on hab battery when we are in motion?

Tinca

by Peter Brown Mon May 19, 2014 8:39 am

You don't say what make of fridge is installed so I can't be specific.

All of the absorption type fridges work in roughly the same way and all are intolerant of being at an angle - most specs say they won't operate over 3° from level. This is mainly when used on gas as the flame can miss the flame detector and switch off.

There are 3 heating elements; one gas, one 240v and one 12v. The 12v is the one that is used when driving.

There is a 12v permanent feed from the habitation battery that ONLY facilitates switching and indications it is not used for heating.

There is a connection from the vehicle battery to the fridge 12v heater. The connection is via an electrical relay. This relay is operated by the D+ output from the engine alternator. The D+ feed is only there when the alternator is charging the battery so there is no chance of the 20A feed to the fridge flattening the vehicle battery.

It depends what type of control system you have where the fridge relay and relevant fuses are located. With Sargent systems they are in the EM40 (a grey metal box with a Perspex cover in the middle with fuses behind it). The D+ supply to the relay will also be fused.

I hope that's enough to get you going.

Peter

by bikeralw Mon May 19, 2014 9:54 am

I also had the problem of my fridge not working on 12 volts when the engine was running.
Sorted with a new relay and relay holder.
https://www.autosleeper-ownersforum.com/t8728-fridge-relay

by Tincataylor Mon May 19, 2014 3:21 pm

Peter Brown wrote:You don't say what make of fridge is installed so I can't be specific.

All of the absorption type fridges work in roughly the same way and all are intolerant of being at an angle - most specs say they won't operate over 3° from level. This is mainly when used on gas as the flame can miss the flame detector and switch off.

There are 3 heating elements; one gas, one 240v and one 12v. The 12v is the one that is used when driving.

There is a 12v permanent feed from the habitation battery that ONLY facilitates switching and indications it is not used for heating.

There is a connection from the vehicle battery to the fridge 12v heater. The connection is via an electrical relay. This relay is operated by the D+ output from the engine alternator. The D+ feed is only there when the alternator is charging the battery so there is no chance of the 20A feed to the fridge flattening the vehicle battery.

It depends what type of control system you have where the fridge relay and relevant fuses are located. With Sargent systems they are in the EM40 (a grey metal box with a Perspex cover in the middle with fuses behind it). The D+ supply to the relay will also be fused.

I hope that's enough to get you going.

Peter

Peter,

You must be the motor home equivalent of a national treasure.

The fridge in question is a Dometic RM7291L and the power distribution unit is a PDU4M. I can understand your reply and I can see why there has to be a relay that is operated when the engine alternator is charging so that the fridge does not discharge the battery when the engine is not running. Have I given you enough information for you to know where the fridge relay and fuses are located?

The manual helpfully states under troubleshooting that if the fridge does not function on 12V then the "on board fuse may be defective" and that the action I can take is to "fit new fuse", but it rather unhelpfully omits to tell me where the damn thing is located.

Tinca

by Peter Brown Mon May 19, 2014 3:53 pm

I can't find a note to confirm this but I think you may have the MES power system. On models with that installed their was a motion detector that kicked in at 2-3 mph, disconnecting the habitation circuits and operating the fridge and electric step. If yours is one of those then you will have to be actually driving before the fridge starts to operate on 12v. The idea of that system was that the engine could be run on site to charge the leisure battery without disconnecting the habitation electric's etc.

Again if it is this system then the fridge relay and fuse should be discrete items under the drivers seat as described in the post by bikeralw.

Peter

by oldfred Mon May 19, 2014 6:57 pm

The 12v light on my fridge doesn't come on until I start to move. I think it works on from the same movement detector that pulls the step in.
Fred

by Tincataylor Tue May 20, 2014 7:51 am

Pete, Fred,

Having read the manual once again (I will be able to repeat the damn thing by heart soon) you are both correct in that I have the sensor that dictates that the engine must be running and the vehicle must be in motion before the fridge will operate. If the green light only comes on when the vehicle is in motion (which I think is daft) then I will have to send the wife aft to check when we are on our way up to Upton on Severn this weekend.

As always many thanks to everyone who has provided information; I'm sure I will have other questions when I come to fit the re-fillable gas cylinder. So if anyone has replaced a 6Kg propane with a refillable 11Kg LPG cylinder in a Nuevo and has any advice to pass on please feel free.

Tinca

by Billy Ruffian Tue May 20, 2014 10:28 pm

I replaced the 6kg with an 11kg refillable on my 2012 Nuevo. It was an easy job. I bought all the bits from GasIt.

by inspiredron Wed May 21, 2014 12:01 am

Your electrolux fridge probably has two switches, a large green 240V switch and a half width red 12V switch. They each illuminate when powered and may safely be both left on, except when winterised and left on EHU with fridge door open. It may also have an orange switch for the gas ignition.
Peter's comment on tilt is not quite accurste. If tilted by more than about 5° an absorption fridge will not work as the coolant csnnot circulate. This applies onmains as well as on gas. It Iis possible to permanently dsmage the fridge by operation tilted for too long but then it would not work on any power source, gas or electricity.

by Tincataylor Wed May 21, 2014 8:00 am

Billy Ruffian wrote:I replaced the 6kg with an 11kg refillable on my 2012 Nuevo. It was an easy job. I bought all the bits from GasIt.

Billy,

Thanks for he reply. Did you fit the part of the kit that accepts the garage nozzle to the bodywork or did you just have it in the locker? If on the bodywork, is it a simple DIY job?

Tinca

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