mjt Posted September 5, 2021 Share Posted September 5, 2021 Hi everyone, it's been a long time since I visited the site but will probably look in more often as we're moving our boat to The Broads. Apologies for what will be a long and rambling post but I need to cover everything that I've been doing to fix a problem. After not being used for at least a couple of years due to you-know-what our Electrolux RM4200 fridge now refuses to work on gas. I just can't get it to light up. When I pulled it out of it's housing to begin the investigation I noticed the piezo igniter was sparking inside instead of at the pilot. I decided to try closing up the gap between the igniter electrode and the thermocouple a little to reduce the voltage required and initially this seemed to work. I got the pilot lit and after an hour or so found the freezer compartment getting cold. On the next visit the fridge wouldn't light again so I tried closing up the gap a little more and once again got it to light. This time I tried it again just before we left the boat and again it refused to light. At this point I decided to take a punt on a new piezo igniter. Fitted that and it still wouldn't light. Gas was getting through, we could smell it. I wondered if I'd got too weak a spark with the reduced gap so increased it a little and succeeded in getting a stronger one without any sparking inside the new unit, but it still wouldn't light. Now comes the really weird bit. I tried lighting it while the pilot assembly was still dropped down an inch from the bottom of the chimney and lo and behold it worked - reliably, time after time - but as soon as I pushed the assembly back in position in the chimney it stopped working. I could still see a spark and smell gas but it wouldn't light. I'm now completely stumped so if anyone has any insights I'd be extremely grateful. Quote Link to comment Share on other sites More sharing options...
annv Posted September 5, 2021 Share Posted September 5, 2021 Hi Mike check chimney for obstruction, the jet gets corroded clean and then prick out the jet they get obstructed by rust from chimney then make sure the spark is shorting at the top of jet not lower down. John Quote Link to comment Share on other sites More sharing options...
mjt Posted September 5, 2021 Author Share Posted September 5, 2021 Hi John, thanks for your reply. The spark is definitely passing between the electrode and thermocouple tip when the assembly is dropped down. When it's in place it's not easy to see whether it's moved. I'd have thought if the gas is building up to the extent we can smell it it should catch. Next time I'm over I'll try to get a small bottle brush up the chimney and check the jet. Again, though, once it's lit it seems to have a good flame pattern so I'd be surprised if it's obstructed. We're now wondering if it's time to bite the bullet and replace with a compressor fridge. I installed an Isotherm in our last boat and it was brilliant. The only deterrent to spending the money is that realistically we may be giving up after another couple of seasons due to age and health issues. Quote Link to comment Share on other sites More sharing options...
annv Posted September 5, 2021 Share Posted September 5, 2021 Hi Mike The spark needs to contact the gas exiting the jet the thermo coupling is a safty device to cut the gas supply if flame go's out, a gas fridge is far better than a electric one, (safty aside) keep it f you can while it still works Quote Link to comment Share on other sites More sharing options...
mjt Posted September 5, 2021 Author Share Posted September 5, 2021 I can't agree there. A compressor fridge is far more efficient than a gas one. The 12V heater for the 3-way Electrolux is about 100 Watts and consumes 8 Amps. A compressor motor takes about 2 Amps and the average current when taking the cycling into account is more like 0.8 Amp. Plus, as you've admitted, it's far safer especially if someone is sleeping in that cabin (I have installed new CO monitors in both cabins by the way). I do understand that the spark needs to be in the gas flow although as the gas builds up in the pilot assembly I would still expect to get some ignition, even if it's the kind that blows the flame out. I also fully understand the principle of a thermocouple as a flame safety device. I think the Electrolux is quite fussy when it comes to the positioning of the spark and the cleanliness of the jet. I've been pondering why it worked with the pilot assembly detached but not with it in place and the only logical explanation seems to be that either the gas flow from the jet is being influenced by the presence of the chimney or the spark is going via a different path. Quote Link to comment Share on other sites More sharing options...
WherryNice Posted September 5, 2021 Share Posted September 5, 2021 Could it be a problem with the supply of combustible air rather than the flue/gas? Not sure on layout of these things but just a thought. Quote Link to comment Share on other sites More sharing options...
Vaughan Posted September 5, 2021 Share Posted September 5, 2021 WHOA! Everybody stop just for a moment, please. Do not let's PXXX about with gas fridges on an Internet forum. The most likely problem is that the flue has got rusted up and needs brushing out with a special flue brush. This will allow the correct flow of air up the flue to burn the pilot light with a proper blue flame. It is the flue getting hot, which creates the heat exchange which makes a gas fridge work. If the flue is rusty it doesn't get hot enough and the fridge does not cool down. The pilot light just heats up the flue. If the flue has got rusty this is because it has been installed with the exhaust pipe at too long a length out to the hull, so the exhaust gases are vaporising before they can escape. The exhaust for a gas flame consists ONLY of CO2 and water. A fridge flue needs cleaning out at the start of EVERY season. You must NEVER attempt to clean the jet of a gas fridge. If it is not burning properly with a blue flame then the jet must be replaced. The aperture in the jet is TOO SMALL to be cleaned by pricking. If you do that, the jet will burn with a white flame and emit CARBON MONOXIDE into the boat. Gas fridges are excellent, but they must be serviced every spring and this MUST be done by a Gas Safe approved fitter. 4 1 Quote Link to comment Share on other sites More sharing options...
Vaughan Posted September 5, 2021 Share Posted September 5, 2021 21 minutes ago, Vaughan said: If the flue has got rusty this is because it has been installed with the exhaust pipe at too long a length out to the hull, so the exhaust gases are vaporising before they can escape. Excuse me - for the technical amongst you, when I said vaporising I meant condensing, of course. If the exhaust gases go through too long a pipe, they will condense and drip back down the pipe, which will rust the flue in the fridge. 3 1 Quote Link to comment Share on other sites More sharing options...
Smoggy Posted September 5, 2021 Share Posted September 5, 2021 Bin it and buy the compressor fridge, gas fridges do work but live in the past. BUT.... They are not cheap and if a quick fix keeps you boating go for a quick fix. Quote Link to comment Share on other sites More sharing options...
mjt Posted September 5, 2021 Author Share Posted September 5, 2021 3 hours ago, Vaughan said: If it is not burning properly with a blue flame then the jet must be replaced. I can put your mind at rest on that one. When I have succeeded in getting it to light it is a perfect blue flame - no yellow or other colours present - and as I stated in my initial post it does cool with the pilot alight. I wouldn't be at all surprised if there were spider webs in the flue. They seem to get everywhere else. My instinct is to do as Smoggy says - bin it and get a Gas-Safe fitter to seal off the end of the supply pipe. I'm certainly not throwing any more money at trying to get it going. Thanks to everyone who replied. 1 Quote Link to comment Share on other sites More sharing options...
annv Posted September 6, 2021 Share Posted September 6, 2021 Hi Mike the great advantage with a gas fridge is it runs for ever on a bottle of gas and are silent unlike electric ones fine on mains but three or four days before battery i goes flat unless you run engine for two/three hours every day and on a boat at night they are not silent. John Quote Link to comment Share on other sites More sharing options...
mjt Posted September 6, 2021 Author Share Posted September 6, 2021 Well, since moorings on The Broads are limited to 24 hours the engine is likely to be run every day. Yes the compressor does make a noise but on our old boat I slept in the cabin near the fridge and didn't find it obtrusive (and my hearing was a lot better in those days ). I've found that I can get an 85-Litre fridge in the space but annoyingly everyone seems to be out of stock of that size. Quote Link to comment Share on other sites More sharing options...
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