My Horizontal G6RA Series 80 Nordyne, cycles every 20 min. or so of continues usage, and the error code is one blink: Limit Circuit open or External Load on W. I installed a new circuit board for another issue earlier (press. swith closed) now it works great but won't stay on continuesly without going off than on again. The only limit switch this unit has are: Supply air, vent switch, and a flame roll-out. Which one is it??? I don't think is the external load on W !??!!! Any Help Folks???

Got another big problem guys - my lungs are under constant stress from a very dusty house - made worse when I run this monster Jet-Air cleaner in my basement workshop while using the table saw or other sawdust generating power tools (the exhaust from this unit is like that of a jet engine, thus the name, I guess.... ;) ) [url=http://www.amazon.com/gp/customer-media/product-gallery/B00004R9LO/ref=cm_cmu_pg_setImg/182-6787309-6620811?ie=UTF8&totalImages=9&pageSize=10&sort=rating¤tImagePage=0¤tImagePageOffset=8¤tImageID=mo1MFT7JQF3B9FN&action=setImg&page=0]Customer Image Gallery for JET 708620B AFS-1000B 550/702/1044 CFM 3-Speed Air Filtration System with Remote and Electrostatic Pre-Filter[/url] Backstory: When I was considering what furnace to buy I also explored filtering options offered by the local Trane dealer, decided to go with the massive Aprilaire Model 2210 accordion-style filter system for an additional $325 to cut down the dust levels upstairs - with my old furnace and simple filter I had to install an additional 14" x 14" x 1" filter in the hall air return vent to capture additional dust the furnace filter was allowing through. Worked okay, but not good enough (yes, I know it's generally a bad idea to increase the air resistance in the ductwork like that, but I was desperate, ok?) The installers had to put in the housing for the filter, which bumped out the furnace's vertical return duct far enough that they had to remove the old ductwork and install a new "chimney" with a curved 90 degree bottom piece to feed into the filter housing (old system fed the return straight down the side of the furnace). No problem, had the room for it, the basement is unfinished and 50% occupied by my workshop/laundry areas....except after almost 4 months I am 100% convinced that all the return air is somehow bypassing the filter! My father has the identical Aprilaire system in his (much larger) house, he's close to 80, widowed, by no means a neat freak, and I never see any dust on his furniture - I mean nada, zippy, zilch - one of the reasons I bought the filter unit. I expected to have a shiny clean house after everything was installed and working, but nothing changed as far as dust levels, in fact without the air return filter now I think it's actually worse! And things get [I][B]much[/B][/I] worse after working in the shop while using the Jet-Air cleaner, it's almost like someone goes upstairs while I'm working and empties the contents of a vacuum cleaner bag all over my house, especially on my beautiful antique bedroom furniture. They were the 1st set of furniture my Dad's parents bought when they married, were nearly destroyed by the time I got my hands on them (Gramps eventually turned the dresser into a drill press table for his shop!?!), I rebuilt/refinished them many years ago, they're gorgeous and irreplaceable, they just don't make stuff with that kind of scrollwork and intricate inlays any more. Anywho, I digress.....tend to do that, so bear with me folks...... Over the weekend I pulled the filter out to inspect it - the manual says to replace it every 6 months, been 4 months now - to my shock, it looked brand spanking new! :eek: Even worse, when I fired up my air compressor to blow out what I assumed would be a massive amount of dust, nothing came out, and I mean NOTHING - not a single puff. I called the dealer, explained what was going on, and they sent out a tech this morning to check things out, but he wasn't the brightest bulb in the bunch, unfortunately, a simple grunt - no offense intended to any other grunts here, of course :) He pulled it out, poked and prodded things, and announced "there's no issue here"....IOW, you're out of your mind, the dust is a figment of your imagination. BS! So I turned on the compressor again, blew air through the filter and said "see? there's nothing in it!". He remained unconvinced....so I pulled the pre-filter off the Jet-Air cleaner shown above, blew air into it, and billows of dust came flying out - and that's a cheap $3 filter, not an 85% capture 3-10 micron capable filter like the Aprilaire's! I again asked him why the difference, why is the furnace filter spotless, he just shrugged his shoulders and said "I dunno, but there's nothing wrong that I can see" - I told him that wasn't an answer, something is blatantly wrong here, have your boss call me to discuss this, as I am NOT a happy camper. (it's now 5:47 pm, no callback, surprisingly lousy customer service for an up until now extremely courteous and helpful company). Any ideas from the pros here about what might be amiss? A couple things I noticed while we were inspecting things: 1) There are metal flanges on the top and bottom of the filter that slide into matching flanges in the housing, so there's no way air is getting over or under it. 2) The edges seal from simple compression of the filter flaps against the side of the housing and the cover - they bend, IOW. 3) Both sides of top portion of the filter were bent up, the bottom edges were bent down, but right in the middle they were just kind of "smooshed" in a random fashion - that's where I think the problem lies. It appears there's no way to get a repeatable and reliable outer seal with these filters - every time you take it out and put it back in the edges bend differently, with no guarantee the gaps will seal 100%. I can think of a couple possible solutions if my suspicions are correct: 1) Have them install a new filter, as this one may be permanently kinked and never seal properly. 2) Install weather stripping on the downstream side of the edges of the housing to block air from taking the path of least resistance, which is the questionable side seals. 3) Or would it be better to put the weather strip right at the edges of the filter so the flaps compress against it instead of bare metal? Any and all ideas, ways to troubleshoot/test the edge seals, potential solutions, or "I've seen this happen before stories" welcome! TIA guys.