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Miller CMF 80 problems

Posted by madams0384 (My Page) on
Mon, Jan 24, 11 at 1:18

I have an oil fired Miller CMF 80 oil furnace. It currently has half a tank of kerosene and diesel fuel, that were also treated with Power Service fuel treatment. It has a single line for suction and return that is located on the top of the tank and is pulled up so that it doesnt feed off of the bottom of the tank (it actually will run out at 1/8 of a tank). I installed a fuel filter that is located in line in a canister (the tank is 10-15 years old, and never had any problems up until last year). It has a brand new filter as of one week ago, and the canister and all fuel lines were cleaned out with carburator cleaner. The small, round, mesh filter located within the pump was removed and cleaned as well. The eye was also checked and cleaned, even though it wasnt dirty. The furnace was installed this past fall, and was brand new at the time. The problem i am having is, I plug nozzels (or so I think) constantly. The air coming from the duct work smells like faint exhaust, while the exhaust coming from the chimney burns cleanly. If you look inside the fire box from the door or where the nozzel and gun go into the furnace, everything looks clean and new. If I put in a new nozzel (60 80 B as the door instructs) it will plug anywhere between one week to 24 hours. I even tried reverting to a 60 80 A like the manufacture originally had in it, and it still pluged within 24 hours. I have five nozzels and one in the furnace on hand right now, and as one plugs i take them and clean them and hope to get through the night because today is Sunday Night at 1:15am and they are plugging within minutes. I am in PA and the temperature is sub zero and I have three kids here with me. I am here posting because I am finally to the point I dont know what else to do. It should also be noted, this past week when it would begin to pump fuel and spray into the furnace, the blower would kick on as it should. It would run for ten to fifteen seconds before the blower would shut off and the furnace would continue to burn and the blower would kick on again. Tonight it has gone to a new extreme. It is constantly (the blower) kicking on and off while trying to raise the temperature back up to my desired setting. This is new territory for me with a furnace, I dont know what else to do. I have checked everywhere for leaks, kinked lines and have come up empty handed. Please, if anyone has any ideas, dont hesitate to post. Thank you in advance.

Follow-Up Postings:

RE: Miller CMF 80 problems

where is your fuel filter in relation to the burner? typically outdoor tanks/ tanks which take oil from any location other than the very bottom of the tank will accrue quite a bit of water. This water is usually very acidic and full of black sludge/alge (which is why you should always take the fuel from the bottom of the tank and pitch it properly) This acidic moisture will periodically get into your elevated line and cause the copper line feeding the burner to flake and corrode internally. If the fuel filter is not placed almost immediately before the burner, the flakes of copper will go through the pre-pump screen and clog the nozzle. (with a setup like this I would reccomend at least two filters anyway, with at least one right before the burner). Also be sure your nozzle isn't coking up- if the nozzle depth in the firetube isn't set properly and the nozzle is protruding substantially beyond the retention head the heat of the fire will cause the fuel to coke up inside the nozzle. If the firebox of the furnace is that clean, you might be firing your burner with too much excess air thus creating a fuel smell in the house and leading to overheated coked nozzles. If the flame is very bright white try moving the air band setting on the burner to the point where the flame becomes yellow and begins to smoke from the flame tips, when this happens open the air band just enough to eliminate smoke, and then open it just a bit more. that should get you in the ballpark to where the furnace will run reasonably efficiently if the adjustment somehow got horribly off.

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