tallphil Posted September 21, 2015 Share Posted September 21, 2015 Hi all, I have an Electrolux RM4211 three-way fridge. On a recent trip it developed two faults with the electronic gas ignition, both of them intermittent: 1) On operating the gas ignition switch, there is no spark for a minute or so (sometimes the delay is only seconds). Then the spark starts clicking and the gas will light 2) When the gas is lit, the spark continues clicking. I have to turn the switch off to stop it. It will eventually stop by itself, but takes ages. At the end of the trip I replaced the ignition module with a new one. This fixed problem (1), but not problem (2). So I now have a reliable spark when I flick the switch, the gas lights fine, and stays lit when I release the knob. But the spark continues to click unless I turn the switch off. Can someone please tell me how the ignition module senses that the gas is lit? Is there another component I should replace? (I'm assuming the thermocouple is okay since the gas stays on once lit). Thanks, Phil. Link to comment Share on other sites More sharing options...
thebishbus Posted September 21, 2015 Share Posted September 21, 2015 I had a similar problem with my fridge after cleaning the burner assembly and flue. The igniter kept sparking until I switched it off. My spark plug tip is bent at right angles where it comes out of the ceramic insulator . When the fault was there, I had the tip pointing down at the burner. Which seemed to be the right way for it. I turned the spark plug round so that it's tip pointed up to the thermocouple, that solved the problem, I can only presume that top part of the flame was hotter, therefor sending the signal to the igniter to turn off. Brian B. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted September 22, 2015 Share Posted September 22, 2015 Phil The RM4211 fridge is a pretty old model (User Manual here) http://www.manualguru.com/electrolux/rm-4211/users-manual and I’m pretty sure I had one in my first motorhome (a Herald). Like Brian B, having completely dismantled and cleaned the burner-assembly, I found that - after reassembly - the igniter continued to spark even though the gas-burner was clearly properly alight. I don’t recall the exact design of my fridge’s igniter tip, but I remember disassembling/reassembling the burner again and the sparking problem disappearing. From what Brian has said (and what happened in my case) it’s possible that the position of the igniter in the burner-assembly is significant and that, if you experiment with repositioning the igniter, you may be able to stop the excessive sparking. Link to comment Share on other sites More sharing options...
tallphil Posted September 22, 2015 Author Share Posted September 22, 2015 Thanks very much Brian and Derek, yes I too have the right-angled electrode tip, and I too have taken it apart and might have put it back together pointing a different way. I'm pretty sure it was pointing down, but since I was in a lay-by in Germany at the time, memory is a bit hazy. At least that is something I can try. However, I started getting this problem before I fiddled with it. So are you saying the spark electrode is also a heat sensor that switches the spark off when hot? I will try repositioning/rotating it as you suggest and see if that helps. Phil. Link to comment Share on other sites More sharing options...
Silicongyro Posted September 22, 2015 Share Posted September 22, 2015 Phil I also have an old Electrolux 3 way fridge/freezer - model 6505. possibly a little younger than yours. I had igniter problems some years ago, which I solved by a replacement compatible igniter ( the German original then out of production). In sorting out my issues out I found out how the unit works and bench tested the module and replacement module to confirm. This may also be relevant to your unit - you to judge ! Firstly the spark generator is actually a reigniter rather than an igniter. This means it constantly checks the flame integrity and restarts the high voltage pulses to create sparks if the flame extinguishes for any reason. So in normal operation, should the flame be blown out it will be automatically be re-lit. The way it achieves this is by exploiting the fact that the resistance through the ionised gases in a flame is significantly lower than through air. The reigniter unit measures the resistance between the probe tip and the "earth" terminal of the reigniter unit - doing this between the HV pulses. This in turn means you need to pay attention to the following points to ensure the resistance measuring current path around the circuit is OK 1. Ensure probe tip is touching the outer part of the flame 2 Ensure the connection from the reigniter to the frame ( the chassis or earth connection) is good (not loose or corroded) Then the low voltage circuit from the reigniter probe, the ionised flame gas, the brass flame tube, the fridge chassis, the reigniter earth connection should be complete and once a flame is lit current should flow and trigger the reigniter to stop HV pulses. Note that only about 5 mA flows in this measuring circuit - so connections have to be good. Trust this helps ! Link to comment Share on other sites More sharing options...
Derek Uzzell Posted September 23, 2015 Share Posted September 23, 2015 The general principles of the re-igniter are described in this Electrolux document http://www.club80-90.co.uk/pages/downloads/tech/RM212Elect.pdf but it’s very helpful to have the fine detail and advice provided by Silicongyro. Link to comment Share on other sites More sharing options...
tallphil Posted September 23, 2015 Author Share Posted September 23, 2015 Thanks very much, that is fantastic, now I understand how it works. When I first dissembled my burner, I noticed the spark jumps between the electrode and the tip of the thermocouple - I wonder if that is correct. I imagine the spark gap is quite crucial in being able to make sufficient current flow when the flame is lit to turn off the igniter. Anyway I will take it apart again and check the spark is inside the flame. I'll also try reducing the spark gap if I can. Phil. Link to comment Share on other sites More sharing options...
tallphil Posted September 29, 2015 Author Share Posted September 29, 2015 Well, I've now removed the burner assembly and cleaned everything thoroughly. I've reassembled it with the bent-tip electrode pointing in every possible direction, and with spark gap of every size, but it still continues to spark when the flame is lit. I've read everything on the internet about the gas ionisation/rectification detector it uses (there isn't much, there don't seem to be many people around who understand it). I even did an experiment with a small gas-cartridge stove which I earthed to the back of the fridge. I took the electrode in a pair of pliers and held it in the stove flame. I could not make the sparking stop - at any distance, any angle, it just kept on sparking. So I'm not convinced the flame detection works at all. I have already replaced the ignition unit. Now I'm wondering if a new electrode and cable might help. I really don't want to spend more money unless it's going to solve the problem. I've read other forum threads where people have just given up trying to fix this problem, and just turn the ignition off at the switch when they can feel heat at the upper grille. Can anyone help me further? Thanks Phil. Link to comment Share on other sites More sharing options...
Bulletguy Posted September 29, 2015 Share Posted September 29, 2015 tallphil - 2015-09-21 6:35 PM Hi all, I have an Electrolux RM4211 three-way fridge. On a recent trip it developed two faults with the electronic gas ignition, both of them intermittent: 1) On operating the gas ignition switch, there is no spark for a minute or so (sometimes the delay is only seconds). Then the spark starts clicking and the gas will light 2) When the gas is lit, the spark continues clicking. I have to turn the switch off to stop it. It will eventually stop by itself, but takes ages. tallphil - 2015-09-29 2:25 PM Well, I've now removed the burner assembly and cleaned everything thoroughly. I've reassembled it with the bent-tip electrode pointing in every possible direction, and with spark gap of every size, but it still continues to spark when the flame is lit. I've read other forum threads where people have just given up trying to fix this problem, and just turn the ignition off at the switch when they can feel heat at the upper grille. Can anyone help me further? Seems like you've gone to an awful lot of trouble Phil and i admire your persistence!! My fridge is the RM4213S and when i first bought the van the igniter wouldn't work at all so had to have a new one fitted. After a couple of years mine started doing exactly the same as yours....clicking away like crazy even though the gas was lit. I just turn the igniter off now. As long as it's lit the gas i'm happy. I always check through the small 'peephole' at the fridge bottom inside that it's lit. Link to comment Share on other sites More sharing options...
Silicongyro Posted September 29, 2015 Share Posted September 29, 2015 Phil Sorry to hear your continuing troubles. For what it is worth, this is the experimental lash-up I configured to check my replacement reigniter would work before installing it in the 'van. This was all done away from the van - not involving the fridge, gas supplies etc. In a man cave I attached (clamped) the reigniter onto a sheet of metal, which was itself gripped in a vise. I made sure the reigniter "earth" connection was properly made to the metal sheet. The metal sheet was gripped so that it was vertical. I then connected the reigniter to a source of 12v (or thereabouts !) - this being a small portable TV power supply unit in my case - while holding the probe tip close to the sheet - 5 to 10mm or so. I then had a continual series of sparks to the sheet. Once satisfied the reigniter was producing a regular series of sparks ( incidentally, horizontally to the sheet - needed for next stage) I lit a candle and brought the flame up to the gap where the sparks were jumping. The sparks immediately stopped. If I removed the flame, the sparks would immediately restart . This was repeatable at will. If you were to repeat this you should get the same result if your reigniter module is working. if you do not, then I suggest to check the reigniter. If you do, then this should provide a working baseline for you to move the arrangement to your fridge. All it should need is a candle flame to bridge the gap. Best of luck Link to comment Share on other sites More sharing options...
thebishbus Posted September 29, 2015 Share Posted September 29, 2015 If you still have the problem with the spark plug tip in the hottest part of the flame, it could be a break in the ignition lead , or at the spark plug connection. The spark would jump the break but there would be no electrical; path for the switch off signal to the ignition unit. Brian B. Link to comment Share on other sites More sharing options...
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