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HEATING OIL AND ITS PROPERTIES
* 65% of petroleum processed is used for transportation.
* 9% (only) is used for heating and electric generation.
* most oil heated homes use #2 heating oil.
* 1/8" of soot in oil burner is too much.
* some are heated by kerosene or #1.
* heating oil, natural gas, propane and coal are fossil fuels.
* fossil fuels are made from prehistoric plants and animals that form fossils. we also call them hydrocarbons.
* carbon is a solid and if not totally burned becomes smoke and soot.
* bonded together hydro carbons can be a gas like propane, liquid like heating oil, or a solid like candle was.
* hydrocarbon gases contain more hydrogen.
* hydrocarbon liquids and solids contain more carbon.
* the buried petroleum comes in two forms crude oil and wet gas.
* they are lighter than water and are forced upward from where they were formed.
* the lowest temperature at which there is a momentary flash which promptly goes out.
* the point where the fuel is just behinning to vaporize, but there is not enough vapor to support combustion.
* heating oil will not burn in liquid state. it must be heated till it vaporizes.
* the american society for testing and materials (ASTM) specify the flash point of #1 and #2 fuel oil is to be 100 F degree.
* most states call for higher flash points from 130 F degree and as high as 214 F degree.
* this makes oil a very safe fuel for home heating.
* the lowest temperature at which rapid combustion of a fuel will take place in air.
* #2 fuel oil, the ignition temperature is 637 F degree.
* the lowest temperature at which fuel will still flow.
* the ASTM standard for #2 is 20 F degree.
* fuel sold is normally lower than 20 F degree. it can range from 0 F degree to -55 F degree.
* #2 fuel oil will not flow in subzero weather unless it is stored indoors or in an underground tank.
* the temperature at which was crystals begin to form in the fuel.
* typically 10 F deree to 20 F degree above the pour point.
*** there is no way to check but it is bad for ignition. ***
* these crystals can clog filters and strainers restricting fuel flow.
* the resistance to flow, it is the thickness of the fuel.
* viscosity varies with temperature
* colder oil will have a higher viscosity it will be thicker and effect burner performance.
* poor atomization, delayed ignition noisy flames, pulsation and possible sooting.
WATER AND SEDIMENT
* water in tank bottoms is undesirable since it leads to the formation of sludge.
* sludge is largely oil and water mix.
* water and oil usually do not mix but if organic sediment is present it acts as a binder to stabilize an emulsion of the fuel and water.
* this forms a white milky substance that will not burn.
* ASTM limit for water is 0.1%
* most fuel sold ranges around 0.05%
* most of our water problems are not from refiners.
* usually we pick up water from delivery and storage.
* sulfur exists in varing degrees in all fossil fuels.
* sulfur content is between 0.5% and 0.05%
* ASTM maximum is 0.05%
* when burned sulfur mixes with oxygen to form sulfuric oxide gas.
*** steam (gas) vs. liquid ratio relationship is 1700 : 1 ratio.
* as a gas sulfuric oxide is not a problem as long as the fuel gas temperature stays high enough to prevent steam from condensing.
* when condensed, water from the steam mixes with the sulfuric oxide to from sulfuric acid.
* sulfuric acid is very sticky.
* sulfuric acid sticks to the heat exchanger and leaches out the iron.
* this creates iron sulfates (white crusty stuff we call scale)
* scale makes up 50% of the deposits on heat exchangers.
* blocks fuel passages restricting air flow and increasing soot and smoke.
* occasionally we find a form of sulfur called mercaptan sulfur in the fuel ( stuff added to natural gas that to give it an odor).
* mercaptan sulfur can attack brass parts in the fuel handling system (jelly like corrosion product) and can only be removed by manual cleaning.
* industry is working on lowering the sulfur contents in heating oil (low sulfur diesel fuel).
* using low sulfur fuels all but eliminates the formation of scale and soot.
* heating oil is normally the color of champagne. for tax compliance reasons heating fuel is dyed the color of cranberry juice. this identifies heating oil from on the road diesel fuel.
* the dye causes no problem for burners.
* fuel is very light sensitive even top quality fuel will darken quickly when exposed to light.
DETECTING OUT OF SPEC. FUEL
* first clue fuel is not within ASTM spec could be a sudden rash of problems: delayed ignition, smokey fires, noisy flames dirty fire, and soot accumulation.
* only competent laboratories can test the fuel but the cost is very expensive.
* this is very uncommon problem.
FUEL RELATED SERVICE CALLS
* the oil heat industry has done extensive research into fuel related service calls.
* first is the age of the oil tank, the population of oil tanks in the field is aging.
* we are not replacing tanks as fast as we did in the 40's and 50's
* rust and sediments build up in the tank as it ages.
* second factor is the age of the oil in the tank
* oil breaks down over time - oil has a shelf life.
* this can be treated with a stabilizer additive ( hot fuel oil treatment )
* third and probably the biggest problem is the size and speed of delivery.
* blasting oil into a tank too fast kicks up all the sediment and rust in the bottom of the tank.
* solutions are not to let the level of oil in the tank get too low.
- * water enters the oil tank in the following ways:
- - condensation (the most reason)
- - broken tank gauge (outside)
- - loose or missing fill & vent caps.
- - delivery trucks
- - leaking vent, fill pipes or tank
- - pumping old oil into a new tank (least reason)
- water is heavier than oil so it settles to the bottom.
- bacteria is everywhere... water, air, and soil.
- 1 pinch of soil can be home to 10,000,000 bacteria.
- bacteria grow in water and double every 20 minutes.
- bacteria feed off certain fractions of the fuel.
- they break the fuel down into hydrogen, CO2, carbon rich residue.
- they generate sticky slime or gum to protect themselves.
- this slime binds the bacteria, the residue, the water, and the fuel together to form sludge.
- sludge grows at the water-fuel interface.
- sludge is a natural product and forms in all oil tanks eventually.
- may not cause problems for years.
- two things cause sludge to get suspended in the fuel are low tanks levels and fast deliveries.
- biological active sludge is corrosive.
- it will slowly eat the tank from the inside.
- bigger problem is when sludge is stirred up, suspended and drawn downstream.
- sludge plugs fillers, strainers, and nozzles. it also sticks on the inside of fuel lines pitting and plugging them.
- the solution is to not let it get started in the first place.
- make a habit of checking tanks for water.
- if water is present, remove it and find out where it came from
- treat the tank with a fuel conditioner.
- dispersant breaks up the slime binder and destroys the stickiness.
- allows remaining small particles to get trapped in the filter or burned.
- corrosion inhibitor protect the tank and lines while the sludge is dispersing.
- bio-sides kill the bacteria (only after the protective slime is destroyed).
- anti-oxidants retard fuel degradation.
- in some cases the sludge build up can be so great you are better off replacing the tank.
CUTTING OFF LINES HIGHER IN TANK
* the theory: no longer suck the sludge and water off the bottom of the tank. this just postpones the inevitable. the jungle in the bottom of the tank just continues to grow and get bigger problem.
ANSWER/SOLUTION TO SLUDGE & WATER PROBLEM
- * pull the oil right off the bottom.
- * water condenses in all tanks & cannot be prevented.
- * burners will tolerate a little water in the oil.
- * if we burn up the water as it condenses by pulling oil off the bottom it will not have a chance to build up & allow sludge to form.
- * always pitch a tank slightly toward the suction end and draw off the bottom.
- * until the mid 70's all heating oil was straight run distillate, it was stable. now it is less tolerant for storage, heat and exposure to catalysts like copper.
- * the dynamic new fuel is more liable to clamp together and form long lumpy hydrocarbons molecules forming an insoluble unburnable particulate.
- * this is the dull back stuff on nozzles, strainers, and filters (the shinny black grease - like stuff is sludge)
- * passages in the nozzle are smaller than a human hair
- * it takes very little contamination to plug up these passages
- * quality oil filters are a must
- * there are a wide variety of filters
- * basically two categories:
- cartridge type vs. spin on type
OIL BURNERS (SPECIFICATIONS)
- * oil smells
- * soot stains
- * must have proper tools
- * drop clothes, rags, newspaper, gloves, booties, odor gone
- * oil container - paint can works well
- * vacuum cleaner - must be soot master
- * avoid any oil or soot complaints
- * turns combustion blower and fuel unit
- * 1725 - 3450 RPM ( if you don't see the rpm then look pump motor to find out rpm b/c it has same rpm)
- * cw or ccw rotation
- * manual reset overload
- * diagnosis like any motor
- * when locked up ensure it is the motor and not the fuel unit (fuel pump)
FUEL UNIT (FUEL PUMP)
- * pumps fuel to nozzle @100 psi
- * 1725 - 3450 rpm matches motor
- * cw or ccw rotation
- * single stage or two stage
- * model number of fuel unit will give all specification
- * single or two pipe application
- * single stage used in single pipe installations (gravity used) or low vacuum requirements if below 6" wc
- ex) oil tank is above the burner
- * two stage used in installations (tank below burner) 6" wc vacuum requirements or greater but not over 15" wc
FUEL UNIT TESTING
- 1. ensure pump strainer is clean
- 2. ensure oil filter is clean
- 3. ensure pump is primed
- 4. confirm bypass plug in or out
- * rule - never more than 1 plug.
- * returned plugged no bypass plug
- * returned not plugged bypass plug in
- * plug in = 2 pipe system
- * plug out = 1 pipe system
CUT OFF CHECK
- * attach gauge to nozzle line
- * start burner 100 psi on gauge
- * turn off burner and psi will drop to approx. 80 psi and should hold
- * attach gauge in line with nozzle line start burner raise
- * pressure to 150 psi on gauge
- * observe flame
- * should not sputter or die down, reset to 100 psi
VACUUM TEST (PUMP ITSELF) NOT IN LINE
- * install gauge on inlet line to fuel unit start burner and ensure unit is primed
- * close supply valve
- * single stage should pull 20" wc of vacuum
- * two stage should pull 25" wc of cacuum
- (vacuum test vs. vacuum requirement on line are different)
- * provides air to support combustion
- * direct coupled to motor
- * ensure its clean
- * connects motor to pump
- * various shaft size adaptors
- * can be cut to size
- * ensure not to short or long
- * check for cracking and splitting or stripped ends
- * provides spark to ignite fuel air mixture
- * primary voltage 120v.
- * secondary 10,000 v.
- * look for leaking tar insulation
- * check amps while sparking
- * use transformer checker
- * control burner via thermostat
- * provides flame safeguard circuit via cad cell
- * 45 sec. lockout standard
- * 15 sec. lockout for mobile homes
- * flame sensing eye
- * changes resistance via light
- * 2 million ohms in darkness
- * 500 ohms in light
- * ensure it can see the flame
- * ensure it is clean
- * carry spark to nozzle assembly
- * no pitting or burnt marks
- * no cracks
- * no heavy carbon build up
- * must be gapped properly based on degree, angle of nozzle
- * atomizes fuel into combustion chamber
- * do not touch face of nozzle or filter with finger tips
- * filter must be tight
- * sized in gallons per hour to match input
- * degree angle matches combustion chamber configuration
- * never change angle or gph
- * applies to two pipe system ( most two pipes system)
- * 1" vacuum = 1" vertical lift
- * 1" vacuum = 10" horizontal run
- * 1" vacuum = per fitting
- * install gauge in line on supply and start burner and note gauge reading
- * low vacuum = leak in line
- * high vacuum = restriction in line
- * OSV = oil safety valves ( negative pressure check valve)
- * on inlet to the pump should be not over 2 psi
- * old/standard oil furnace
- - draft in over fired @ 0.01" wc ~ 0.02" wc @ 45 degree to 55 degree outside
- - flue draft @ 0.02" wc ~ 0.04" wc greater
- ex) 50 degree outside
- over fired draft 0.06" wc
- flue draft 0.08" wc
- the damper is wide opened.
- (symtom is over drafting, doesn't give enough time to transfer heat in heat exchanger. needs put another damper.)
- * warm outside less drafting, cold outside more drafting.
- * chimney creates draft, and damper regulator controls the draft.
- * after first elbow in flue run
- * must be level
- * gate must swing freely
- * same size as flue run
- * weight must be accessible for adjustment
- * controls draft in combustion chamber
- * open, it creates less draft.
- * clese, it creates more draft.
- * nozzle and oil filter must be new
- * pump operation must be checked
- * transformer must be checked
- * combustion blower must be cleaned
- * heat exchanger, flue, flue crock, and chimney must be cleaned.
- * 1/8" of soot is equal to 1' (12") of insulation
MAKE INITIAL SETTING
- * adjust to clean flame with sharp tips
- * must have smooth start up and shut down (no delay, no pup noise)
- * operate furnace to bring up to operating temperature
- * used to check negative pressure
- 1. check over fire draft should be 0.01"wc ~ 0.02"wc
- 2. check flue draft should be 0.02"wc ~ 0.04"wc greater than over fire
- 3. adjust barometric damper to obtain proper readings. if damper is wide open must add second damper
SMOKE SPOT TESTER
- * used to check smoke in combustion products
- 1. use clean smoke paper
- 2. insert in flue
- 3. pump 10 times slowly
- 4. compare to smoke chart
- 5. adjust primary air to achieve a smoke spot of between 0 ~ 1
- 6. any adjustments made to draft or smoke, you must recheck both till draft and smoke are within range
- * used to check % of CO2 in combustion products
- * insert in sampling hole in flue
- * pump 18 times holding last pump and release from co2 indicator
- * invert 3 times
- * read co2 level on gauge
- * old style burner 7% ~ 9%
- * new style burner 95 ~ 11%
- * flame retention burner 11% ~ 12%
- * reduce primary air will raise co2 reading (delute the air)
- * watch all readings and recheck all with any adjustments you make
- * insert in flue and let temperature settle out
- * lower the stack temperature the higher the efficiency (related to airflow. double check)
- * keep thermometer clean
- * using stack temperature and co2 reading to read efficiency
- * be careful some kits work on net stack:
- total stack - ambient = net stack
- * some work on total stack
- * know which one you have
- * cycle a few times to ensure smooth start up and shut down
- * clean up area very well
- * remove any old oil parts from job site
- * apply odor gone powder or spray to reduce oil smells in furnace room