Laser 72 wont fire up
I have just been inside my 72 for the same reason. Have you cleaned the burner pot and heat exchanger lately? If not it is time. What makes these things work is a burner mat in the bottom of the pot that will eventually go bad. if this occurs you must change it out, if it looks good ( looks unburned) and whole and attached to the pot then your problem is with the igniter or with the combustion sensor or a clogged fuel pot inlet fitting. The first thing I would check is the easiest, disconnect the fuel line from the inlet to the pot, remove the screws and pull it out, it may be kind of stuck in there so a little rotation usually helps. When out, hold one end up to a light and see if you can see unobstructed light through it, if not, clean it out using a piece of wire or if you have access to a set of acetylene torch tip cleaners use those until it is good and clean, re-install and try that. If no good I would disassemble the burner pot and heat exchanger and give it a good cleaning and inspection. If you go that far there are a couple of things to watch out for. First is when you go to remove the burner ring it comes off in a counter clockwise rotation, there are three pins set in the pot that hold it in place and if they are carbon encrusted it won't want to turn and DO NOT I repeat DO NOT try to horse it off, you will break the upper burner ring mounting arms and I have been told by my parts guy that they are unobtainable now. I speak from experience, I did it and had to weld it back together, no big deal if you can but if you have to take it to a welding shop it will cost you a few bucks. My suggestion is to take a large flat blade screw driver or better yet a brass or steel rod about a quarter of an inch in diameter and go down along side the upper ring and LIGHTLY tap around the lower ring to try to loosen up the gunk and try again, keep this up as long as you have patience and hopefully it will come out. If not you can send it to a Toyo repair station or horse it out and have it fixed. When you get the ring out the next issue after a good vacuuming and cleanout is the igniter unit, it will be stuck and if you cannot turn it you can heat up the burner pot around it with a propane torch until very hot and let it cool and repeat a few times until you can get it out, ( I suggest either taking the pot outside or running your shopvac over it when you do it) if you break the ceramic it will cost close to a hundred bucks to replace. If you are still with me, now for the cleaning part, if the burner mat has lifted from the bottom of the pot anywhere, it must be replaced and it will be burned up in the places this has happened. Give it a good scrape down and shining up with sand paper until no carbon or old glue remains and vacuum clean and wipe it with a solvent until clean. The new burner mat comes with a tube of adhesive and it takes about half of it to secure the mat down, a thin even coat is needed with no puddling, use a small one inch chip brush to coat it and brush it all in even strokes in one direction and then 90 degrees off to create a cross hatch pattern. Place the burner mat down and using your fingers press it into the adhesive until you have covered the whole mat, do not leave any piece unpressed. At this point you can clean out the heat exchanger by flushing it out with a hose outside, be warned, it is messy, lots of carbon and soot come out so pick a suitable location like a cleanable sink or out back somewhere. One other thing, when you go to remove the large gasket that seals the burner pot top to bottom, take piece of rigid paper, like a cereal box, and carefully slide it onto it and back on, don't pick it up by any means, it will crumble and you will have to spend another thirty bucks or so. I have learned most of this from my local parts guy and from the school of hard knocks, so I hope this helps. JP
