rowlie Posted March 17, 2017 Share Posted March 17, 2017 I am refurbishing a motorhome and have had to replace the fridge. The original was made byCamping Gaz. I am fitting an Electrolux 3 way fridge. when connecting the electrics there appears to be no pointers as to polarity. The 240v connecter block has brown wires leading from it and there is no indicators as to which is the feed or return. This is the same for the 12v side. Does it matter as to which way round the wires are connected to the fridge. (other than earth which is highlighted). Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 17, 2017 Share Posted March 17, 2017 It would be helpful if you provided the model number (eg. RM212) as it’s quite likely that on-line there will be a manual for it containing a wiring-diagram. Link to comment Share on other sites More sharing options...
Dave225 Posted March 17, 2017 Share Posted March 17, 2017 If it was Camping Gaz fridge then you need to ascertain if it was a UK model or EU. If the latter as is likely then there is no polarity in wiring for EU electrics as there are fuses in the main system. What you could do if in doubt is fit an inline fuse to the live feed from your Main box and take it from there. I am guessing that the motorhome if fitted with such a fridge originally is not a UK model. If so, then as mentioned there is no polarity for devices as we have. Have a look at any soickets and see if they are 2 pin Schoko type, or possibly someone at some stage has swopped them for UK ones By the way are you sure it is a Camping Gaz model? I have not actually seen a built in fridge from them, but would not deny they exist. Link to comment Share on other sites More sharing options...
Robbo Posted March 18, 2017 Share Posted March 18, 2017 The OP is replacing the original Camping Gaz fridge with a 3 way Electrolux. The Electrolux will undoubtedly be an absorbtion type fridge with heating elements for the 12v and 240v operation. The heating elements function like any other similar electrical heating device by using a high resistance coil to produce the heat. As far as I am aware, it doesn't matter which way the electricity flows in order to heat up the element. Perhaps others will be able to confirm that the 12v and 240v connections are not polarity sensitive. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 18, 2017 Share Posted March 18, 2017 Rowlie’s motorhome is CI-made (it might be useful to know the model if that’s possible) based on a 1990 Ford Transit chassis and (from this earlier thread) presumably left-hand drive. http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/I-need-your-valued-advice/46077/ Electrolux/Dometic installation/operating manuals can be searched for here http://www.dometicmanuals.com/PROD/MASTERDometic.nsf?Opendatabase The installation section of the manual for an Electrolux RM4270 appliance (just as an example) suggests that there is NO ‘polarity’ regarding the positive and negative wires of the 3-wire 240V connection cable (though the earth wire must, of course, be attached to the appropriate highlighted earth connector on the terminal-block). The manual’s wiring diagram suggests that there IS ‘polarity’ regarding the positive and negative wires of the 2-wire 12V connection cable, with (looking at the rear of the fridge) the positive wire being attached to the left connector of the terminal-block and the negative wire attached to the right connector of the terminal-block. I would think that Electrolux would have standardised on the 240V connection being ‘polarity insensitive’, but I’d be less confident about the 12V connectiion. I would also have thought that, if the 12V connection were ‘polarity sensitive’, the terminal-block would be suitably “+” and “-“ marked. Within an Electrolux fridge there’s normally a label that carries the model reference. Failing that, it should not be too difficult to identify the fridge model via GOOGLE from the fridge’s characteristics (size, age, etc.) Once the model has been established a manual for it can be downloaded. (Camping Gaz used to market 3-way fridges way back when. I’ve attached a photo of a T618 model that was quite popular.) Link to comment Share on other sites More sharing options...
aandncaravan Posted March 19, 2017 Share Posted March 19, 2017 Without knowing the Fridge being installed I wouldn't like to say definitely this applies, but almost all modern 3 way Fridges require a permanent positive and negative feed to the Electronics which control all three phases of operation, Gas, 12v and 240v and is needed to power the Digital displays, etc. Polarity of this supply is important. This 12v supply is in addition to the 12v 'switched' Element supply, the 240v Element supply and the D+ now also used on most modern Fridges.. While generally Fridges have a 12v heater element which isn't polarity sensitive, some Motorhome constructers 'Earth' the negative 12v cable. Obviously that would give the Motorhome a 'Polarity' sensitive nature on the12v Elements negative, even though the Fridge may not be. I must point out I am not a Fridge expert, hate working on the things because of access, so avoid them whenever I can. Rowlie, if the original Fridge didn't have a 12v D+ feed to trigger it, for example the old Fridge Alternator 12v supply to the heater element was powered from a relay under the bonnet, it can be fiddly to get a feed from the Alternator all the way to the new Fridge. The usual solution many techies used to adopt was to fit a Voltage Sensing Relay that 'triggers' when the Starter battery voltage goes above 13v, as it assumes the Alternator is now spinning. Problem is many Motorhomes now have charging of the Starter battery from mains and Solar which raise the Starter battery above 13v, which might trigger the Fridge to switch to 12v. If you can't easily run a cable (Yellow is the European Colour standard) then consider an Ignition switched supply to simulate D+, but you need to flag up in the documentation somewhere for any future owners that if anyone leaves the ignition on without the engine actually being started, i.e. to listen to the Radio, there might be complications? Link to comment Share on other sites More sharing options...
rowlie Posted March 19, 2017 Author Share Posted March 19, 2017 Thanks for your respnse to date. The model is RM 4236. There is existing wiring from the original fridge which was a three way item. All wiring diagrams i have found so far show the wiring on the fridge side of the connection block as being polarity sensitive. or at least colour coded.The wires on mine are all brown and i cannot see any indication in the region of the connector block to suggest polarity. Link to comment Share on other sites More sharing options...
aandncaravan Posted March 19, 2017 Share Posted March 19, 2017 The 230v wires are not polarity sensitive, so just make sure the earth is right. The 12v Element leads (they will be fatter than the 230v) you can put into a screw block connector to keep them secure so they don't touch each other or anything else. Then start up the engine and check their voltage with a digital volt meter. The meter should show which one is positive +. Then put a circle of Red tape round the positive and a circle of Black tape around the negative for future reference. You then need to bring a permanent live and a D+ to to the back of the Fridge. Most older Fridge installations didn't need them, but I am pretty sure your new Fridge will. When the Fridge is working, before you install it fully, check that the voltages are all as would be expected, especially that the Fridge '12volt' element is getting close to 14.4v from the Alternator. If the new Fridge is bigger than the old, or the Element is a higher wattage, carefully consider if the cabling is up to the job? Many older installations were only just adequate. We worked on an 2006 Autotrail for G.N. last Thursday that had a Fridge that didn't work efficiently on 12v. We found the supply to the Fridge was only just 13v from the Alternator, at the best of times. Probably less than that at others. Link to comment Share on other sites More sharing options...
rowlie Posted March 20, 2017 Author Share Posted March 20, 2017 I have had a good look at the connections and note the following The 12v is routed through a switch with three terminals. Checking continuity it would suggest that the central terminal would be a feed as it would isolate the 12v when not in use Continuity between the central terminal and the two outer ones is only achieved when the switch is on. This to my mind is the logical way. likewise with the 240v The wires are roiuted through what looks like a double pole switch. By checking continuity I have wired it so the feed goes trhough the switch then to the temperature control relay before going to the heaterAgain this would isoliate the unti when not in use. Any comments appreciated. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 21, 2017 Share Posted March 21, 2017 I believe the Electrolx RM4236 model of fridge has a piezo iginter for gas operation - so one less thing to worry about regarding electrical wiring. The appropriate Electriolux manual for it would be the RM4230 one that can be downloaded from here http://www.dometicmanuals.com/PROD/MASTERDometic.nsf?Opendatabase How CI would have wired up a motorhome to be fitted with a Camping Gaz fridge in 1990 is anybody’s guess, but you’ll certainly need to arrange for 12V-operation to only occur when the vehicle’s engine is running. Link to comment Share on other sites More sharing options...
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