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Nozzle Plugging

Mark Berry
Mark Berry Member Posts: 15
I recently serviced a mobile home furnace with an outside tank.I replace nozzle and pump strainer(strainer was spotless) no oil filterin system. Customer called me one week later, no heat.
When I arrived all tests ok, plugged nozzle, replaced nozzle,all ok.
Another week has passed, no heat again. Customer bled oil line, clean flow(no air). I sold him a spare nozzle on the last call(his request), he swapped out the nozzle and the heater fired up.
I use Hagos double filtered nozzles and have had very few problems with them. I have heard of people putting varnish in the oil tanks to pay them back for some wrong doings. The nozzles have appeared to be clean each time and suspect this is the case. Customer has two 275 tanks tied together. Is there any way to tell if the oil is contaminated.


  • john@TR
    [email protected] Member Posts: 26
    \"plugged\" nozzles

    It's actually pretty rare for a nozzle to be "plugged". Most often what actually happens is more of a distortion of the spray pattern or a failure to atomize fully. When the burner doesn't light and the tech condemns the nozzle by saying it "plugged" it just adds to the largely undeserved reputation of oil heat as being dirty. Oil heat doesn't deserve that rap but some oil techs do. If you find repeated calls for failed nozzles in a mobile home furnace you ought to check for a cracked heat exchanger or positive draft over the fire. Heat reflection (on the off-cycle) from the ceramic fiber chamber can actually cause damage to the nozzle and the reddish-brown tinge associated with this is sometimes referred to as "varnishing". If there is a draft or heat exchanger issue it will magnify any heat related nozzle problems. If there aren't any positive draft problems and you still have nozzles going south on you, you might want to try filtering the oil before it gets to the pump. I don't care how clean that strainer was, it still is no substitute for good (micron level) filtration. You also might want to check those oil tanks for water. And how many years have they been exposed to the elements? If there's a gauge on one of them you almost certainly have some water in there too.
  • Mark Berry
    Mark Berry Member Posts: 15

    Thank yoy for your input. I did inspect the heat exchanger, new gaskets,checked "z" dimension", pump pressure. Performed efficiency test, co2 level same before and after blower comes on. I do not believe that the furnace is cracked(two years old). Draft is fine -.04"w.c.
    I could try filtering the fuel. I live in a town with 15 mobile home parks very few have filters in line even the bottom feed ones, I know that does not mean this one is a problem but I have never had the double filter nozzles give me trouble This customers tanks are top feed.
  • Ken D.
    Ken D. Member Posts: 836

    I like to use the Delavan Del-O-flow nozzle for low firing rates. Many of the nozzle manufacturers have a similar No Plug nozzle. I also use an extra nozzle filter for that little extra protection. They are available aftermarket or already installed in nozzle. I also use 2 oil filters for the problem jobs. A standard 25 oil filter closer to the tank with a Garber or Wix filter as a secondary closer to the burner. Not a bad idea to make standard procedure for all burners. These precautions do work.
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