Philip M Posted August 21 Share Posted August 21 I've recently bought an Eriba 320 which was manufactured in 2021 but for various reasons has only been used twice and the fridge, a Dometic RM5330, had never been used on gas until I bought in June this year. On the first couple of trips the fridge went out once every day over a four day period. On the next outing it ran for five days without error. On a further occasion it went out daily again, but then ran for four days and so on over several outings adding up to 23 days in all. Of the 23 days it's failed on eight of them. I have been exchanging numerous texts with a retired Dometic gas engineer who has very kindly been trying to help me, but he hasn't been able to come up with a reason for such erratic behaviour. However, I have been able to amass some circumstantial evidence as pointer to what might be happening. I've been wracking my brain to try to think what could cause it to run for 120 hours without error and then have three days where it fails every day. 1. It only fails in the afternoon. 2. It's always on full flame when it fails, and relights immediately. 3. It has never failed at night. 4. It's virtually new and completely unused. And then it occurred to me. It only fails when the sun is on the front of the van. If the van's facing North, or the weather is dull it works perfectly. In other words if the gas locker is in the shade. Perhaps being an Eriba and having an aluminium body is something to do with it, or maybe the fixed 30 Mbar Cavagna regulator, which the sales people fitted new when I bought it, is somehow at fault, I don't know. I would be very pleased to hear if anyone here has had a similar experience or has any thoughts to what is causing this behaviour. Thanks. Quote Derek Uzzell https://content.invisioncic.com/a321943/monthly_2023_03/images.thumb.jpg.22eb4f5c434a62f266f9d6cdbff27487.jpghttps://content.invisioncic.com/a321943/monthly_2022_07/14_GrandMaster.svg Moderators 23.1k Posted 5 hours ago The large Dometic RM7651L AES fridge/freezer fitted to my 2005 Hobby T600FC motohome used to occasionally fail to relight when running on gas. There was no pattern to this behaviour, but I noticed that a couple of wires that plugged into a module on the fridge's rear did not look 'tight' in their sockets. After I had firmed up the wires' connections, the problem did not reappear. (Possibly sheer coincidence or the effect of the repeated curses I made when the fridge shut itself down.( (Even though you have an Eriba caravan, you might want to copy your enquiry to the Motorhome Matters forum where it will get more exposure.) Quote Link to comment Share on other sites More sharing options...
Philip M Posted August 21 Author Share Posted August 21 Thanks Derek, Having swapped my motor home for the Eriba I wasn't sure I would be welcome on the Motoehome forum. With regards to the fridge going out when the front of the van is in direct sunlight, I think I have now solved the problem. I've just returned from six days away where I spent three sunny days with van facing South and fridge going out every day. I the turned it around to face North and the fridge ran for three days (68 hours) without trouble. Which adds more evidence to my theory, albeit circumstantial. This morning at about six o'clock I noticed that the fridge was on full flame but burning with less vigour. Being a bit chilly, I lit the gas fire only to find it would go out every few seconds and then relight. I have fitted a replacement Truma regulator just a couple of hours ago and everything is working fine again. Obviously only time will tell. What I think might be happening is the Caravagna regulator, which I believe was faulty from the beginning, and was fitted new when I bought the van in June this year, increases its pressure above 30 Mbar when it gets warm causing the fridge gas flame to lift and blow itself out. This morning when it was cold the pressure must have dropped sufficiently below 30 Mbar such that the gas fire was starved and also reducing the flow to the fridge. I had plenty of gas in the bottle. I don't know if my theory is right and I will have to see how things go on over the coming weeks, but I am in little doubt that the temperature in the gas locker is the source of the trouble. I have been using two different gas bottles, one Flogas and the other one a refillable Gaslow bottle and the results have been exactly the same. Is it likely that a regulator could behave in this way? Quote Link to comment Share on other sites More sharing options...
Alanb Posted August 22 Share Posted August 22 All regulators work by comparing with a reference value. In case of fixed lpg regulators, the reference will be atmospheric pressure. Having inspected a spare propane regulator in my workshop, I can confirm the presence of a small vent hole on the upper side of the regulator, but it could be the front if the regulator was mounted vertically. If the vent hole becomes blocked and the regulator is subject to a considerable rise in ambient temperature, then the pressure on the reference air side of the regulator diaphragm will increase as the air trapped inside expands. The regulator will respond by increasing the outlet pressure to match the required 28mbar above what it falsely senses as ambient pressure. As the temperature inside a gas locker, which probably only has dropout vents at the bottom, can rise considerably when in direct sunlight, my theory seems plausible. Perhaps Phillip M could check for either a blocked, or missing vent hole on his original regulator? Alan Quote Link to comment Share on other sites More sharing options...
Philip M Posted August 22 Author Share Posted August 22 The regulator is mounted vertically above the gas bottles. I have just had a look at the vent hole which faced downwards and without taking the it apart it looks to be clear. The problem only occurs when the sun has been on the front of the gas locker for some time, when I turn the van round the fridge runs perfectly day after day, so it has to be heat related. The only other oddity was on a cold morning the gas pressure seemed to be reduced, although I'm running on propane. I have of course fitted another new regulator an all appears well at the moment. 1 Quote Link to comment Share on other sites More sharing options...
Philip M Posted August 30 Author Share Posted August 30 Well, the new regulator didn't fix the fault, in fact it's made considerably worse insofar as it goes out every few minutes to a few hours now. I don't think it's an electric contact fault because I've actually watched the galvanometer when it fails and it falls slowly as thermocouple cools suggesting the connection is good. Although it burns with a blue flame it roars away like a brazing torch with too much air. I am now thinking the problem is with the gas jet/burner and I am inclined to replace it. There was a very interesting post here on 27 April 2021 by robdav. Apparently I need a CBs2 piezo Dn65 by way of a complete replacement burner. (apparently it's no longer possible to buy the jet on it's own). There are several of them readily available on the web, but they have an additional nine digit number which might the fridge product code? The only supplier that asks for my product code is Leisure Shop Direct and they tell me there is up to three weeks wait to get it, but the won't confirm how long until I pay. If I buy a CBs2 Dn65, is that sufficient information to be sure it will work in my fridge or does the part have to have the exact product code attached? Can anyone help me with this as I can't find anyone to ask online. Thanks. Quote Link to comment Share on other sites More sharing options...
Philip M Posted September 2 Author Share Posted September 2 HELP! I think my van may be fitted with a Fridge that was intended for the German market with a 50 Mbar gas jet and I'm not sure what to do by way of a replacement part. Having done everything I can and failed to sort out my problem I decided to buy a replacement burner. I've managed with difficulty to find the part number for the burner which is CBS2-DN65 However, I came across this picture with the leaflet showing CBS2-DN65 as 50 Mbar. The van was built in 2020/21 during the covid troubles and I wonder if this has something to do with it. Dometic doesn't make the RM 5330 any more and I fear ordering a replacement from the product code which places an order to Germany to have one built may well produce another wrong part. I have done pretty much everything I can think of: Replaced the regulator, stripped and cleaned the burner/jet with brake cleaner, cleaned the flue, dissembled the gas valve, blown through the pipes, cleaned the gas valve end of the thermocouple, and bypassed the selector contacts. All to no avail. It goes out very intermittently and it's almost impossible to nail down. Given this van was fairly new and the gas had never been used, I know for certain the fault was present from day one. It's pretty difficult to get any gas spares suppliers to deal with an individual, let alone speak to you. Any advice on what I should buy to replace the burner? Quote Link to comment Share on other sites More sharing options...
Alanb Posted September 2 Share Posted September 2 It would seem that what you require is a CBS2-DN16. Follow this link to Ebay, and see if anything matches your burner. Alan Quote Link to comment Share on other sites More sharing options...
Philip M Posted September 2 Author Share Posted September 2 Thanks Alan, There's certainly a CBS2-DN17 that looks like the right one. If I have got a 50 Mbar jet in my fridge would it be likely to cause it to go out very intermittently? I have to say since I changed the regulator, if anything it's got worse which might be explained by tolerances in pressure. It might also explain the temperature effect. The trouble is it's impossible to pin down. Quote Link to comment Share on other sites More sharing options...
onecal Posted September 2 Share Posted September 2 Hi Was there a back pressure regulator VDR 50/30 fitted Regards Quote Link to comment Share on other sites More sharing options...
Philip M Posted September 2 Author Share Posted September 2 Sorry, that should have read CB2S DN16. What is the difference between the 16 and 65? No. there isn't a back pressure regulator fitted. I think perhaps I have this wrong. My van was manufactured in 2020/21 and I have just read that Europe including Germany changed from 50 to 30 Mbar before my van was made. Quote Link to comment Share on other sites More sharing options...
onecal Posted September 2 Share Posted September 2 Hi The 16 = 30 mbar (CB 52- 16) The 65 = 50mbar (CB52- 65) (Corrected - was 60 = 50mbar) Quote Link to comment Share on other sites More sharing options...
Philip M Posted September 2 Author Share Posted September 2 Thanks Onecal. So to be clear, when I removed the gas burner and cleaned it, the 65 stamped on the brass gas jet would confirm that it is definitely for use at 50 Mbar. It would be good to be sure as it would likely solve my problem. Also, I have since read that Europe have changed to 30 Mbar. Presumably that includes Germany. When did they change? Quote Link to comment Share on other sites More sharing options...
onecal Posted September 2 Share Posted September 2 Hi I am not so sure that it may be your outright issue It would normally be fitted with a 50mbar regulator if it was . You removed the one that came with your vehicle and replaced it with ? Did you replace like with like? Have a look at the manufactures rating label plate and see what it says ? (Serial No etc') . This information is so important Try operating your supply control change over switch many many times between Gas and DC and ensure this is operating correctly first as this is a well known issue with same on the gas side of things when it's not been operated over a long time Worth a try first , Regards Quote Link to comment Share on other sites More sharing options...
Philip M Posted September 2 Author Share Posted September 2 The van was made for the UK market. I have looked at the information on the fridge and it does state the gas pressure as 30 to 37 Mbar. Likewise on the hob - a point I missed earlier, but I did wonder if the wrong burner could have been installed in error, particularly as the world was shut down with covid when it was made. The gas goes out intermittently. Sometimes it will run for days other times it's hours which makes it difficult to apply any logic. In my last post I listed all the things I have done which included shorting out the gas selector terminals with a wire loop, but it still failed. Because it always seems to fail when on full flame (it's never failed at night during 23 nights use) and because I measure a steady 35 mV from the thermocouple, I don't think it's an electrical fault. Nine years ago I had a brand new Elddis Accordo that had a pretty similar fault. The gas jet was replaced under warranty on that occasion - the engineer said it was a know fault. It never failed again. I think I will replace the gas burner/jet, I can only try replacing parts now. In reply to Onecal, I'm still unsure if your saying the 65 stamped my jet confirms it's for 50 Mbar pressure. If it is it's been fitted in error. Quote Link to comment Share on other sites More sharing options...
onecal Posted September 2 Share Posted September 2 Hi Again I can only point you to the simple well known faults on this model. One being the manual switch change over switch as I mentioned (dirty contact in the multi-switch disconnects the flame failure device) The burner complete unit and gas pressure regulator (must match the model nameplate and Serial Number on the RM 5330 model) Without actually seeing the appliance all it is ,is guessing and thats not good practice just throwing parts at it I would advise as you say you have tried all the simple things to be replaced, as above it is most important Is to have the unit checked by a qualified Gas engineer who is trained to work on these appliances, after any work has been carried out Regards Quote Link to comment Share on other sites More sharing options...
Philip M Posted September 3 Author Share Posted September 3 Thanks Onecal. You are of course quite right, I need to order the right part in accordance with the model and product code numbers on the fridge, otherwise I might accidently introduce an additional fault. I've been living with this problem for three months now and the circumstantial evidence I've gathered plus all I have done to try to find the cause (as I set out earlier) leads me to think replacing the gas burner is my next logical move. Quote Link to comment Share on other sites More sharing options...
Derek Uzzell Posted September 3 Share Posted September 3 12 hours ago, Philip M said: Also, I have since read that Europe have changed to 30 Mbar. Presumably that includes Germany. When did they change? This link refers to the 50mbar gas pressure. https://www.gok-blog.de/en/2017/11/06/can-i-operate-30-mbar-gas-equipment-if-the-caravan-or-motorhome-gas-system-has-50-mbar/ I can't tell you in which year German leisure-vehicle manufacturers switched from 50mbar to 30mbar, but it was well over 20 years ago. I have a 2001 edition of John Wickersham's book "The Motorcaravan Manual" and this says about gas pressure regulation The practice adopted abroad often differs. In Germany, for example, current installations now operate at 30mbar; previously, older installations operated at a higher pressure of 50mbar. This has implications for anyone purchasing a secondhand motorcaravan abroad. I once owned a Hobby TC-600 motorhome, bought new from a German Hobby dealership in 2005 (left-hand-drive, German specification) and this had a simple 'on-bottle' 30mbar regulator. All the gas appliances (hob, Truma heater, Dometic fridge) were designed to operate at 30mbar and I would have been amazed if that had not been the case. You say about your fridge "...it always seems to fail when on full flame...". This suggests to me that you believe your fridge has a sort of 'throttle' that increases or decreases the strength of the gas flame according to the amount of cooling needed. Although this used to be the case - with fridges having a pilot-light that kept the gas-burner continuously alight - more modern fridges operate ON or OFF on gas, with the gas burner at 'full flame' or completely shut down. You've also said "...it burns with a blue flame it roars away like a brazing torch with too much air...", but my Hobby's Dometic fridge's gas burner was just the same, as was the burner of the Thetford fridge fitted to my 2015 Rapido motorhome. This is normal, though it may be startling for caravan/motorhome owners used to old-tech pilot-light fridges. It's most unlikely that, in 2021, any Dometic 3-way fridge intended for installation in a leisure vehicle would have been built to operate on 50mbar. So - whatever is wrong with your fridge - it's not due to it having been built to operate on the 'wrong' gas pressure. This firm offers parts for Dometic 5-series fridges https://rvinstallations.co.uk/product-category/dometic/5-series-fridges/ Quote Link to comment Share on other sites More sharing options...
Philip M Posted September 3 Author Share Posted September 3 Thanks Derek. Good, that's put that idea to bed. I thought Germany still ran on 50 Mbar. It was when I saw the picture of the gas valve that I posted yesterday that I panicked instead of taking the time to check more carefully. It does indeed state on the plate inside the fridge that it is designed to run on 30 to 37 Mbar. This fridge does have a pilot setting. Its lit by holding the gas valve open and pushing a battery operated repeater switch. I accept what you say about the roaring, it's just other vans I've had have been much quieter. I'm sure the fridge doesn't have any kind of throttle, the now obsolete RM 5330 is pretty basic. What I have observed though, is it does indeed seem to fail only on full flame. It's certainly never failed in the 23 nights I've used it when the temperature is lower and the thermostat regularly drops to pilot. I also noticed that turning the van so the gas/regulator locker is away from the sun, or if it's an overcast day it's never gone out. That's over a dozen days or so. It also seems to go out more in the wind. That lead me to replace the regulator, and since I have, the problem appears more frequent. All this evidence suggests to me it's a gas related problem. It feels like the flame is being forced too hard and eventually blows itself out. It's very odd that on pilot it's perfectly stable. Quote Link to comment Share on other sites More sharing options...
onecal Posted September 3 Share Posted September 3 (edited) Hi Just as a matter of interest , where in the motorhome is the fridge facing when the sun is shining on the gas locker and does it fail with a door open or window ? Regards Edited September 3 by onecal Quote Link to comment Share on other sites More sharing options...
Philip M Posted September 3 Author Share Posted September 3 It's not a motorhome, it's an Eriba 320 caravan. It makes no difference whether the doors and windows are open or closed. I have just ordered a new burner as per the fridge product code. Apparently I need a: 289 056 796 Dometic Gas Burner Complete CBS1, Piezo, KZ65 for5/8-Series. Which, interestingly, is different from another supplier who quoted for a CBs2 piezo Dn65 from exactly the same Prod No. and parts diagram. It just fills me with confidence! Anyway, it'll take a week or two to get to me. I'll let you know if it solves the problem. Quote Link to comment Share on other sites More sharing options...
onecal Posted September 3 Share Posted September 3 (edited) Hi Sorry for my error I am just so used to dealing with motorhomes Yes the 289 056 796 Dometic Gas Burner Complete CBS1, Piezo, KZ65 is for the 5 series The CBS2 DN65 Piezo, 289060497 is for the newer models Are you using refillable gas bottles ? Regards Edited September 3 by onecal Quote Link to comment Share on other sites More sharing options...
Derek Uzzell Posted September 3 Share Posted September 3 Philip Dometic documentation for the RM-5330 fridge can be found via the following link and (as you've said) this does state that this model has a gas pilot-light. https://www.dometic.com/en-gb/outdoor/motorhome-and-van/fridges/motorhome-fridges/dometic-rm-5330-28251?v=9105704418 My 1996-built Herald motorhome had a 'traditional' Dometic 3-way fridge with a gas pilot-light that could be seen though a small sight-glass in the fridge's rear inner wall. I don't recall it being loud on gas even when the flame was at maximum, but the pilot-light was certainly vulnerable to strong wind blowing against the external lower ventilation grille. The fridge had gas auto-relight, so - if the gas flame did blow out - the fridge would attempt to relight the flame (normally successfully). The fridge was quite tilt-tolerant, but the gas-chimney did need to be 'swept' fairly regularly to prevent soot/debris falling into the burner and, if that did happen, lighting/relighting the gas become hit-and-miss. If the problem persists after the new burner has been fitted and you suspect that it's due to the equipment in the gas-locker being temperature-sensitive, you might try to confirm this by deliberately warming up the locker's interior (say, by putting a hair-dryer in it for a while) to see if that provokes the problem. (I notice that there's an Eriba forum that might be worth contacting if all else fails.) https://www.eribafolk.com/forum.php Quote Link to comment Share on other sites More sharing options...
Philip M Posted September 3 Author Share Posted September 3 Thanks, It sounds like I've got the right part then. The manual shows the manufacturing date as 201027, I'm not sure how to read this but as the van was made in 2021 might this be October 2020? I have been using a 6kg refillable Gaslow for the past three years. Originally in my motorhome and now on the Eriba. But because I had a full Flogas bottle, as the problem has unfolded, I have used both variously and in fairly equal amount, and it seems to make no difference to make no difference to the fault. Out of interest, is there a later model than the series 5? I believe the RM 5330 is discontinued now, but I don't know when it finished. Quote Link to comment Share on other sites More sharing options...
Philip M Posted September 3 Author Share Posted September 3 Thanks Derek, I have joined the Eriba forum and more recently Eriba Folk. I don't know about the latter but there doesn't seem to be much activity on the forum, and certainly very little interest in technical matters. I will perhaps try heating the locker space if the new burner doesn't fix it. I still have the thermocouple and the magnet to change, but as I've said, I don't think the feedback points in that direction. Quote Link to comment Share on other sites More sharing options...
onecal Posted September 3 Share Posted September 3 Hi I ask this because of the history you gave Sometimes the 80% fill cut off fails on some refillable bottles, But as you are sure that may not be your issue there is no point in expanding on that theory You are doing quite a lot of changing and replacing to your gas system Again, please ensure to have the unit checked and certified by a qualified Gas engineer who is trained to work on these appliances, after any work has been carried out Regards Quote Link to comment Share on other sites More sharing options...
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