Fred Duck Posted August 8, 2023 Share Posted August 8, 2023 Our van is fitted with the above fridge. It does exactly what it should when on mains and 12 volt. However, on gas it doesn't work as well as we think it should. It is very susceptible to not being being level - only the smallest amount causes it not to cool or stay cold. Looking on the internet this seems to be a well reported issue with this model of fridge (it seems Thetford replaced many when under guarantee) and whilst we mainly use sites with mains hook up, we do a few times a year stay on temporary site where gas is the only option. Having a working fridge at these times is very important to us. This model of fridge was discontinued by Thetford in 2012 and the current Thetford equivalent is their N4097E that has the same dimensions and looks like it would be a straight swap. However, before taking the plunge, we wonder if anyone has any views, or experience with the replacement model particularly its susceptibility to working on gas when the van is not entirely level? FD Quote Link to comment Share on other sites More sharing options...
Brian Kirby Posted August 8, 2023 Share Posted August 8, 2023 It might help focus responses if you could confirm that this is a 2010 fridge (in your present 2010 Bessacarr E410). Also, have you consulted Thetford on whether there is a fix for this problem, as it is a known issue? If it is true that Thetford did replace many of this model under warranty for exactly this fault, is it possible that you have only recently acquired the van, and that the previous owner did not use it much on gas during their ownership? It just seems odd that the problem was not previously remedied under warranty, or, apparently, was not declared to you at the time you bought the van. Under the circumstances, it seems Thetford, or possibly the seller, might be persuaded to offer a replacement at reduced cost, or to make a contribution to the cost of remedy if a remedy is available. I appreciate that the fridge is now 13 years old, and may well be considered "life expired", but you never know until you ask! Goodwill and all that. 😉 Even if Thetford will not consider a discounted replacement, they should be able to advise whether the N4097E is a straight swap for the N97 SES model in your van, without modification of (especially) the gas pipework connection. Otherwise, if the gas pipework would require mods, it would appear a DIY swap would not be feasible. Quote Link to comment Share on other sites More sharing options...
Derek Uzzell Posted August 10, 2023 Share Posted August 10, 2023 This 2013 Auto-Sleepers Owners Forum (ASOF) thread discussed the 'tilt intolerance' of Thetford N97 fridges. https://www.autosleeper-ownersforum.com/t8305-thetford-n97-fridge The N97's user manual includes no guidance on maximum-tilt; it just advises that the fridge should be level. The complainant in the ASOF thread was eventually provided with a Thetford N3000 replacement fridge under warranty, but the user manual for those models contains the same advice regarding levelling. The issue is not confined to N97 models - this 2021 O&AL forum thread related to a Thetford N4000 fridge https://forums.outandaboutlive.co.uk/topic/52420-thetford-fridge-not-working-on-gas/ Where motorhomes are concerned, insisting that a fridge be exactly level to cool properly would be unrealistic. My 2015 Rapido 640F's stance was naturally tail-up and its Thetford fridge-freezer cooled perfectly well on 12V, 230V or gas and, when I parked the Rapido and ran the fridge on gas, I rarely bothered to level the vehicle. Quote Link to comment Share on other sites More sharing options...
onecal Posted August 10, 2023 Share Posted August 10, 2023 Hi Why not contact Thetford as it's strange the problem was not remedied under warranty by the previous owner One never knows until you ask Regards Quote Link to comment Share on other sites More sharing options...
Fred Duck Posted August 10, 2023 Author Share Posted August 10, 2023 Many thanks all for your replies. I have spoken to Thetford this afternoon and, after some discussion, they did admit that this problem had resulted in some of these and similar model fridges being replaced under warranty. However, that was within a couple of years or so of them being new and as the model was discontinued in 2012, any warranty claim would not be accepted now. Understandable I suppose. They could not confirm whether or not any warranty claim had been made against our fridge without the name of the previous owner. The dealer who we bought from removed all references to his/her name from the paperwork we were supplied with when we purchased in 2019 - Data Protection, Sir. However, Thetford did comment that the latest N4097E 'should' be a straight swap for our unit but, given the passage of time wouldn't, absolutely guarantee that. For the time being, I think we'll look to get the van as level as we can when the fridge is on gas - next weekend and the one after. After that it'll be on hook up when we're away until well into 2024 so I've ample time to .investigate further. FD Quote Link to comment Share on other sites More sharing options...
laimeduck Posted August 10, 2023 Share Posted August 10, 2023 1 minute ago, Fred Duck said: Many thanks all for your replies. I have spoken to Thetford this afternoon and, after some discussion, they did admit that this problem had resulted in some of these and similar model fridges being replaced under warranty. However, that was within a couple of years or so of them being new and as the model was discontinued in 2012, any warranty claim would not be accepted now. Understandable I suppose. They could not confirm whether or not any warranty claim had been made against our fridge without the name of the previous owner. The dealer who we bought from removed all references to his/her name from the paperwork we were supplied with when we purchased in 2019 - Data Protection, Sir. However, Thetford did comment that the latest N4097E 'should' be a straight swap for our unit but, given the passage of time wouldn't, absolutely guarantee that. For the time being, I think we'll look to get the van as level as we can when the fridge is on gas - next weekend and the one after. After that it'll be on hook up when we're away until well into 2024 so I've ample time to .investigate further. FD You should be able to get the name of the previous owner from your V5 registration document I think? Quote Link to comment Share on other sites More sharing options...
Fred Duck Posted August 10, 2023 Author Share Posted August 10, 2023 13 minutes ago, laimeduck said: You should be able to get the name of the previous owner from your V5 registration document I think? Not so any more I'm afraid. Data Protection don't you know!! FD Quote Link to comment Share on other sites More sharing options...
Derek Uzzell Posted August 11, 2023 Share Posted August 11, 2023 Has the gas flue of your fridge been regularly (and scrupulously) cleaned? That the fridge cools satisfactorily when its 12V or 230V heating elements are operating indicates that the cooling system itself is OK. If the gas flue were 'coked up' or the burner's flame were sub par (a problem that came up here in the past) it's quite likely that the efficiency of gas operation might become more sensitive to 'tilt'. 3-way fridges normally have a twisted 'baffle' dangling in the gas flue - if that were missing, it would definitely affect running-on-gas performance. Quote Link to comment Share on other sites More sharing options...
Brian Kirby Posted August 11, 2023 Share Posted August 11, 2023 An excellent point as, if the primary cause of the fault were just the tilt, it would surely fail to function on 240V as well for the same reason (this on the assumption that it is only used on 12V while being driven). So yes, obstructed flue, or defective thermocouple, might well be at the root of the problem. Quote Link to comment Share on other sites More sharing options...
Brian Kirby Posted August 11, 2023 Share Posted August 11, 2023 Just a bit more on this, but it seems that running the fridge on gas while sufficiently tilted to prevent coolant circulation can lead to permanent damage that is unlikely on electricity of whichever Voltage. I gather that the coolant contains a corrosion inhibitor as well as ammonia and water. If the fridge is at sufficient tilt (generally fore and aft) that the inclined pipework at the rear of the fridge is actually level (or in the direction of flow, uphill), so that no circulation takes place, the refrigerant solution in the vicinity of the gas burner or 12V/240V heating elements overheats. The implication is that the gas jet burns hotter than either of the electric elements, at which temperature, if the refrigerant is static and not circulating, the corrosion inhibitor "cooks" and begins to crystallise. Once the crystals have formed they become insoluble and, if the fridge continues to be operated at this degree of tilt, accumulate to eventually completely block the heater pipe in the refrigerant circuit. However, this blockage will affect both gas and electric (mains or 12V) heating sources, as they all work on the same heater pipes. But Fred Duck's fridge apparently continues to work satisfactorily on 240/12V, suggesting that tilt is not the cause of the problem, but is coincidental. Under the circumstances, if the fridge has previously been operated on gas while tilted, resulting in partial obstruction, but not blockage, of the coolant circuit, leaving a sluggish flow, this should affect performance of the fridge equally on all three energy sources. One further possibility for Fred's problem might be a partially blocked gas jet, if the blockage is due to a larger particle in the gas supply pipe that is carried into the jet by the gas flow with the assistance of gravity so as to partially block it, but falls clear when the gas is turned off. However, tilt sensitive dirt particles do seem a bit fanciful! 🙂 Perhaps calling in a Thetford service engineer before doing anything more radical might be worthwhile, with a brief to see if he (presumably! 🙂) can find a plausible explanation for, and fix, tilt intolerance on gas only? Quote Link to comment Share on other sites More sharing options...
Derek Uzzell Posted August 12, 2023 Share Posted August 12, 2023 Thetford's advice about their fridges' 'tilt tolerance' used to be: How level must the refrigerator be? If you have a gas absorption refrigerator, normal levelling of the vehicle is sufficient. The refrigerator is made to operate within 3 degrees off level side-to-side and 6 degrees off level front-to-back (looking at the front of the refrigerator). It's perhaps worth highlighting that the design of a Thetford fridge's gas-burner differs significantly from that of a Dometic fridge. A Thetford burner with a fully alight healthily-blue flame is shown here If a Thetford fridge cools perfectly well on 12V and 230V, but inadequately on gas, the logical first check to make would be to investigate the condition of the gas burner's flame. Quote Link to comment Share on other sites More sharing options...
Fred Duck Posted August 13, 2023 Author Share Posted August 13, 2023 Once again, thanks for your replies and for taking an interest in our issue. I could ask the mobile chap who did the last hab service in May 2022 if he thoroughly cleaned the fridge flue and the burner but I'm sure he'd say he did. I've no reason to doubt that but, in reality, who actually knows. Last weekend, we arrived at a motor sport event and parked in the camping field that is certainly anything but level. At that time, the fridge had been on over the previous night on mains and then on 12v for our journey and it was cold as it should be with the ice cubes frozen. Parked the van as level as was possible but still with a tilt front to back. Fridge on to gas and next morning it had obviously not worked as it should and the ice cubes had turned back to water. Once home, fridge emptied and left turned off until Tuesday morning. The van sits pretty level on its hard standing at home and, as a test I fired it up on gas, filled the ice cube tray with water and waited. After maybe an hour or so ice was just starting to form in the tray and continued until all the tray was fully frozen. It's stayed that way until this morning when I've turned the fridge off and disposed of the ice cubes. On the basis of that test, it appears that the fridge is working fine on gas as it does on the other power sources and the only variable is the front to back tilt of the van and, therefore, the fridge. I think it's time to consult the people at a local, newly opened, caravan/motorhome service centre who have recently carried out a small repair (*) that a local dealer and the chap who did the last hab service said they couldn't do the latter even doubting that it could be done without major dismantling. FD (*) Some might remember my struggle to replace a high level LED marker lamp to the front of the van where the connecting wire wouldn't let the lamp unit pull out so a replacement could be fitted. I'd taken it to dealers and talked to the mobile service man but all said they couldn't help. Visiting Code 11 Ltd in Ossett to look around shortly after they opened their new workshop I discussed the problem with one of their service people who said he'd done this job before and had a way of getting the unit/cable to pull out sufficiently for it to be replaced. Booked the van in, unit replaced and just charged for one hours labour (I had the replacement light unit already). No other connection with Code 11 Ltd other than a satisfied customer. Quote Link to comment Share on other sites More sharing options...
Albertslad Posted August 13, 2023 Share Posted August 13, 2023 Hello Fred, sorry to hear of your problem. Bearing in mind the age of the fridge, I’d not expect much from the previous owner, or from the dealer you bought from. I suppose either party could have removed the aged and faulty item. Instead, I’d look for a replacement fridge that has recommendations regarding non-level tolerance, or I’d look for a non-gas fridge. And Thetford wouldn’t figure. Could be you’ve saved yourself the consequences of doing a straight replacement, and something like £7-800. regards Albertslad Quote Link to comment Share on other sites More sharing options...
Brian Kirby Posted August 13, 2023 Share Posted August 13, 2023 I suppose what you haven't been able to test is whether the fridge runs satisfactorily on 240V if standing on a slope that prevents it working when on gas. There is only one coolant circuit, which is variously operated by 240V electricity, 12V electricity, or gas. So, if the fridge fails on gas when out of level, it should fail equally on 240V electricity when out of level to the same extent. Can you not find a sloping location with 240V power, and try the fridge on both power sources to see if the above proves true? Or even, could you not get the fridge onto ramps at home to induce tilt, and then experiment in relative comfort to see if the defect manifests on both sources. I don't think it's worth worrying over 12V, as this is mainly in use when the vehicle is in motion and subject to all kinds of tilts! It seems as though you mainly encounter this sensitivity to tilt when, for whatever reason, you are on uneven ground and, for whatever reason, this seems to be when you operate it on gas. Rather that the problem being specific to gas operation, it seems more probable to me that it is actually specific to the tilt. Bearing in mind its age, if you intend keeping the van for the foreseeable, I think the (potentially expensive!) solution to your problem will be to establish whether a tilt that stops it working on gas also stops working on 240V, and if it does, replace the fridge with a more tilt tolerant model. Either that - or stick to level ground! 🙂 Quote Link to comment Share on other sites More sharing options...
Fred Duck Posted August 14, 2023 Author Share Posted August 14, 2023 Thanks, again and an excellent point, Brian. As a result, van now reversed onto the top step of its ramps, plugged into mains and fridge turned on with water in the ice cube tray. Will report what happens! FD Quote Link to comment Share on other sites More sharing options...
Brian Kirby Posted August 14, 2023 Share Posted August 14, 2023 Be interesting! 🙂 Don't forget to try same on gas, and if inconclusive, be prepared to try driving onto ramps instead, as the intolerance may arise when nose up but not when nose down. If no result, you probably need higher ramps! It's never easy, is it? 😣 Quote Link to comment Share on other sites More sharing options...
Derek Uzzell Posted August 15, 2023 Share Posted August 15, 2023 A GOOGLE-search on motorhome "thetford" "tilt" will retrieve several discussions about this issue. There seems to be no standard tilt-related behaviour. Some 3-way fridges are clearly very tilt-sensitive, others much less so. The final posting of this 2019 MHFun forum thread https://www.motorhomefun.co.uk/forum/threads/fridge-on-steep-drive.193695/ said Had 2 m/h with dometic full height fridge/freezers neither of which worked on our 20° sloping drive. The Thetford that's now parked on the drive works on either AC & gas .... Quote Link to comment Share on other sites More sharing options...
Fred Duck Posted August 16, 2023 Author Share Posted August 16, 2023 (edited) I think Brian wins the coconut. Fridge doesn't work on mains or gas when tilted to the rear or to the front. Works fine on mains and gas when all but level. Because we've never had the problem on mains, only on gas, I'd assumed that is was a problem with the gas system. However, on mains we always level as best we can on pitches that are pretty level to start of with. On gas, we're normally in camping fields and paddocks at motor sport events where levels can be all over the place. More care with parking or a new fridge (that might be no better) seem to be the two available options. Thanks again, FD Edited August 16, 2023 by Fred Duck Quote Link to comment Share on other sites More sharing options...
Brian Kirby Posted August 16, 2023 Share Posted August 16, 2023 Result! Well done. 🙂 At least you now know that the reason the fridge fails to work at times is because the van is not sufficiently level, rather than anything more complex or costly. You should find that on sloping ground the fridge will still work reasonably well if you can park the van across the slope rather than up/down it, as this should leave the tilt-sensitive part of the coolant circuit more or less level. It also makes getting the whole van reasonably level with normal levelling ramps much easier, as they are then working across the (relatively narrow) track rather than along its (much longer) wheelbase. Might be worth repeating your tests a couple more times to see what happens if you put both ramps on one side to induce a sideways tilt. Then (if you can face it 🙂), repeat with the ramps on the opposite side to see if there is a difference. It's all to do with the way the coolant circuit is arranged. It is at the back of the fridge which, in most cases, is fore and aft in the van. The condenser section of the circuit basically zig-zags back and forth across the rear wall of the fridge to create a more or less even gradient from top to bottom. So, although about half the pipe runs become steeper with the van out of level fore and aft, the other half lose gradient and, because the circuit relies solely on gravity to induce flow, there is insufficient "head" to overcome the increased resistance on the flatter sections. Result? No coolant circulates, so no cooling. However, I understand this effect is negligible where the tilt is transverse, so parking the van level along a slope, and then using ramps to take out any crosswise tilt, leaving the van overall level, not only makes for greater comfort for occupants, but also for the fridge, which will then reward you with cold beers whether on gas or electricity! 😄 Quote Link to comment Share on other sites More sharing options...
Fred Duck Posted August 20, 2023 Author Share Posted August 20, 2023 Final (hopefully!!) update. Another motorsport event this weekend Friday - Sunday parked in a field with no mains. Made a big effort to get the van as level as I could on arrival and fridge worked throughout the weekend on gas just as it should. Beer, Cider and Wine nice and cold and everything as it should be - that was until around 7am this morning when the gas ran out but I can hardly blame the fridge for that!! Mallory Park next weekend for a further test and then it should be on mains after that until next Spring. Once again, thanks all for your interest and help. FD Quote Link to comment Share on other sites More sharing options...
Brian Kirby Posted August 23, 2023 Share Posted August 23, 2023 Quacking result! 🤭 Quote Link to comment Share on other sites More sharing options...
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