Lennox G20 problems

______________________________________________________________________ OK here’s the situation: Our furnace decided to not turn on in the mornings a couple weeks ago when the temps dropped into the 20s. I figured it was the thermostat, so I went out and got a nifty Ritetemp one with the remotes, etc. etc. All was good until today. We have had pretty warm conditions for the past couple weeks, but today the temp dropped back into the 20s, not the teens, and the furnace isn’t working again. The first time round, the house was cold in the morning, and I would have to turn the heat off, then back on at the thermostat, and all was good again. Now it’s doing it every time. Our heat hasn’t kicked in automatically all day. Every time I have had to turn the heat off, then back on at the stat. Once we get it going it goes through the cycle with no problems, but when it cools off in the house again it won’t kick back on. It doesn’t seem to be trying to kick on. Equipment: Lennox G20 Furnace Model #G20Q3/4 E-100-5 Manufactured 5/8/97 Ignition module is Johnson Control G776RGD-11 The reason I mention the ignition module is because I have heard several stories about these being junk. I have read that there is a Honeywell replacement that lennox is telling people to use. However it’s sunday night, and no one to ask. I have not been able to track down a model number for a honeywell replacement for my exact module. Any input would be greatly appretiated. Replies: cable “Re(1):Lennox G20 problems” , posted Thu 15 Feb 19:44 ______________________________________________________________________ Lennox used a Johnson Controls “Ignition Control” module on their furnaces, G26 and some others. This is likely the source of your problem. The LED on the module will be flashing one second on and 5 seconds off. The module fails to supply enough voltage to open the pilot control valve which is part of the gas valve. To verify this problem connect an AC volt meter to the PV connection on the gas valve and ground. Turn off the 115 VAC supply to the furnace and then turn it back on. This resets the control. The normal start up cycle will start with the LED on steady. Observe the burner box and look for the spark to ignite the pilot. You can hear this too. When it is present observe the volage on the meter. It is supposed to be 24 vac. If less significantly you have confirmed a problem with the Ignition Control. These are repairable if you have skills. Otherwise buy a new one. My observations have let me to conclude that the traces and solder connections on the printed circuit board are deficient. You probably will observe a discolored area on the board. Resolder this area and add copper wire to the circuit boards trace that goes to the PV connection. Cable JustAnotherDay “Re(1):Lennox G20 problems” , posted Tue 2 Jan 09:04 ______________________________________________________________________ Here is my story – For about the past month, I’ve noticed that the power venting for the furnance is blowing, but the heat is not coming on. I’ve noticed that the LED on the intermittent pilot ignition control is off (model G776RGD-11). I disconnected the vacuum tube on the venting blower reconnected it, and the furnance would work. But the next time the thermostat called for heat, it would do the same thing. I could also get the heat to turn on by turning the thermostat off – then on again. Just like the previous postings. While doing some trouble shooting, I found that the furnance would come on, then after a few minutes, the flames would shut off, and the vent blower would just continue to run. Luckily, I have two furnances with the same IPI module. I swapped them out – and determined that this module was the problem. Now I’m looking for a replacement. HoosierDaddy “Re:Lennox G20 problems” , posted Wed 23 Nov 19:48: ______________________________________________________________________ This seems to be one of the most common problems on Lennox Whisper Heat. To make a short story long I’ll try to cover everything. (I know NOTHING about furnace electronics) G20Q3E-75-6 with Johnson G776RGD-11 Almost exactly the same symptoms as the original poster. Replaced the thermostat. No go. Started rebooting from the power switch at the furnace. When it didn’t start I could hear a small spark hit in increments of three. ______***______***_______***______ (that will be important later) Did online searches and found a lot of forums trashing the Johnson ignition. Called the repair shop. Repair guy came. Said in this order: 1) Get a new furnace … cheeper that way. 2) They could order a new control board and do it for $400+. (and that might not work) 3) There was nothing wrong with the ignition board. 4) The blower motor was dirty. OK … so 4) I could agree with. Whoever designed the house thought it was a good idea to draw air directly out of the wall instead of using ductwork. Genius! So I start cleaning everything on the furnace. I needed to think about this. While I had everything apart I started ‘playing’ with wires. I’d reboot and move wires while it was doing the spark routine I described before. BINGO! If I move the main wire (orange) leading out of the center of the ignition box it will ‘hit’ every time! I’ve considered trying to fix the connection in the box but with all the bad rep I’ve seen on the G776RGD-11 I’m just going to replace it with a Honeywell. Now what I need to know is how hard will this be. Most of the wire connections look simple enough but the (orange) problem wire goes down and into the burner box. I see it inside but can’t make much of it. (I assume it’s either the ignition wire or the sensor wire.) Any tips or suggestions would be appreciated. UPDATE: WOOOHOOO! Yeah … there’s a loose connection in the box. EDIT : further info relocated here > http://www.hvacmechanic.com/forums/hvacr/messages/13070.htm Clueless [this message was edited by HoosierDaddy on Sat 26 Nov 16:52] mommytech “Re(1):Re:Lennox G20 problems” , posted Sun 17 Dec 18:04 ______________________________________________________________________ Ok – I have had pretty much the same history as you– down to the mechanic’s recommendations (all steps 1-4!) – I’ve been going down to the basement/crawlspace and switching the system off and on. I also figured out if I jiggled the orange wire it starts. Although now that fails me. In reading your report, it seems to be a job I could do. I was looking at it and thinking “if I just knew what to replace it with…” Am I right in reading that you replaced it yourself for about $150 instead of $400 or more? thanks! mommytech HoosierDaddy “Re(1):Re:Lennox G20 problems” , posted Tue 29 Nov 17:39 ______________________________________________________________________ Installed the Honeywell 53L90 Ignition Control. Works great. Had problem with instructions for mounting. There’s no “THIS END UP” in the instructions or on the plate. I finally put the flat part of the new plate up. (‘boxed’ end down) Used holes B & B1 as per instructions but used E & E1 instead of D & D1. Seemed to fit better that way. (not a lot of difference really) Used B for the ground. Green included wire is long enough to go anywhere. Clueless Lulu “Re(1):Lennox G20 problems” , posted Mon 16 Feb 10:40 ______________________________________________________________________ The honeywell replacement is the universal-S8610U 1003. Hope this helps! I just needed one this morning. Lulu dillbert “Re(1):Lennox G20 problems” , posted Tue 20 Jan 12:35 ______________________________________________________________________ I have had the same problem for a week now. The only reason I survived throuh the east coast chill is because I have 2 heating system at home. I have a Lennox G20Q3E75-6 with Johnson Controls G776RGD-11 with Lennox part # 63K2401. First it was once a day then twice a day and a restart of the furnace would fix it. Now I have to restart it 2 or 3 times to get it going. I have cleaned the sensor and checked everything else. When it happens, the pilot comes on and a few secound later the main valve clicks and then immediatley everything shuts down and the led on IPC goes out. Is there a place cheaper than lennox-parts ($139.20 + shipping) to get the part? Does anyone have the actual Honeywell part number? Thanks O’Tool says: Murphy was optimistic. ColdMornings “Re(1):Lennox G20 problems” , posted Wed 7 Jan 19:48 ______________________________________________________________________ I was sure it was the intermittent ignition control, so i did some calling around to the local supply houses. I ended up finding a Johson controls unit that is a replacement for the POS one that came installed. Took all of 10 minutes to replace, and at $96 I’m sure saved me a hell of alot of time and money. 2 days now, and all is well again. I’m sure it would have cost me that much just to have someone some in and say “yeah your ignition module is shot”, then probably $300 more to install a new one. ewag “Re(1):Lennox G20 problems” , posted Mon 5 Jan 05:33 ______________________________________________________________________ try cleaning flame rod it’s that wire in pilot flame with porcelain insulator around middle.scrape with file or sandpaper, knife blade whatever. they get coated & insulated, wont send enough current to control. if that doesn’t help you may need new control nothing lasts forever. good luck rodkoo42 “Re(2):Lennox G20 problems” , posted Sat 19 Jan 17:13 ______________________________________________________________________ I am in a simular situation and I want to make sure I hook up the wires correctly. I am changing a Johnson control pn G765BCA-12 to a Honeywell S8610U 1003. I need some help to make sure I hook everything up correctly. I am concerned about the wire going to the pilot any help will be appreciated RodKoo

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