View OIL BURNER TROUBLESHOOTIN & REPAIRDO IT YOURSELF TUTORTIAL
DEC 25,2010
by eernest4@att.net
Lawrence Montambault
Please read the whole thing if you intend to actually do the job, because I give an overview first to orientent begin-ers, & teach names of parts & then later tell you how to acess burner draw assembly.you could get stuck
if you dont read whole thing & say why didn’t you tell me that first. I tell you now.read it all first.
I start easy first-later give more complated warnings-throughout.!
Spark transformer—- big black box on top or side of oil burner, about 4 in x 6 inchx 6 in
OB =oil burner, NA= nozzle assembly=== consists of nozzle,nozzle oil supply line & electrode assembly
OB blast tube = 4 inch diameter tube that connects OB to furnace, inside the blast tube is the nozzle assembly
& NA oil supply tube 3/8 in diameter copper pipe
OB motor = electric motor , round , usually on right side of oil burner
OP = oil pump, usually on left side of OB , may have either one or 2 – 3/8 in oil supply pipes & one -1/4 or 1/8
inch x 12 in long nozzle supply pipe @ 100 psi
When you turn on your oil burner, on a basic system , only two things happen .
the electric motor that drives the oil pump & the squrill cage fan blower gets electricity and the spark transformer gets electricity.
When the electric motor runs, it drives the fan and the oil pump. The oil pump produces 100 psi on the output which feeds the oil spray nozzle assembly which is also called the drawer assembly because it comes out of the oil burner blast tube as a complete assembly , usually after first removing the spark or also called the ignition transformer.
In order to have a flame , you need to have oil spraying in the proper spray pattern and an ignition spark.
The most common cause of oil burner failure is lack of fuel spraying in the proper spray pattern and the second most common cause of failure is lack of ignition.
These are the two things that you must check for and here is how to do it.
If the burner motor is turning, the fan is blowing & the oil pump is or shoud be spraying. Check to see that fuel oil is reaching the input of the oil pump by cracking open the purge fitting on the oil pump housing. This purge fitting looks just like a automotive brake bleeder fitting. Open it just a little & some fuel oil should dribble out. open it more & fuel oil will gush out about 10 inches, so close the fitting qiuckly to avoid much of a mess.
Now you know that you have fuel oil going into the oil pump and you have also purged the fuel oil pump of any air.
The oil burner man charges $20.00 to do this for you and it is required (in order to get the oil burner running again) on a single stage gravity feed oil pump when refilling the oil tank if you had previously run the oil tank completely empty .
Hint— You know you have a single stage oil pump if only 1 oil supply line feeds it. This oil pump needs to be primed /purged with the oil bleeder whenever the oil supply line goes empty.
Oil pumps that have 2 oil supply lines are double stage oil pumps and are self priming/ self purging because one line supplies oil to the pump and the other line returns unused oil back to the oil tank. The pump only takes the oil it needs to supply the nozzle & returns unused oil as well as all air bound up in the pump and oil supply line, back to the oil tank.
In order to tell if oil is available to the oil spray nozzle, you could look in the fire box by opening the firebox door, WITH THE OIL BURNER OFF, so that you dont get burned & look to see if raw oil is sprayed inside the fire box. You will need a bright light with a reflector, 40 or 60 watts, to be able to see good.
A oil coated fire box means that oil is spraying, but prehaps not enough oil in a distorted spay pattern so that the oil does not burn, or a lack of ignition from either bad electrode settings or a burnt out spark transformer.
Be advised that a wet .oil soaked firebox will make heavy smoke for about 15 minutes until the raw oil burns off. This is because this oil is not burning atomized in a swerling air stream, surrounded by air, but just coating the walls of the firebox. Plan for smoke & close the firebox door so most of the smoke goes up the chimney.
May need a fan & open a outside door. It will clear up in 15 -20 min. tops. If you have any obstructings to the air flow pattern inside the fire box(like newspaper ashs) this should be cleaned out before firing the oil burner
as it will cause bad dirty combustion.
once you determine that the pump has oil but no fire in box & firebox is coated with unburned oil—-
NOTE:(overview— specific directions later)
The first thing to do here is to take out the nozzle assembly from the burner blast tube, unscrew the nozzle from the end of the nozzle supply tube and replace or clean out the nozzle with either carburator cleaner and /or dawn degeasing dishwashing liquid. I use carb cleaner but my friend reports good results with dawn degeasing dishwashing liquid.
THIS IS DONE FIRST BECAUSE IT IS CHEAPEST- NO COST but time TO CLEAN OLD PARTS & reassemble.
Also flush out the nozzzle supply line because it always has some dirt in it just waiting to start to clog up your new or just cleaned nozzle. Use gasoline or clean fuel oil to flush out the line and a cake pan or other large
basin to catch the dirty gas. remember gas fumes can ignite explosivly under the proper conditions so pour the dirty gas outside on the sand- not near a building or car or anything flameable.
If you use a non combustable degreaser, make sure it is completely removed from the nozzle & nozzle supply line, because water based degreaser does not burn & will cause delays & hard start up problems until clean burnable oil gets through .
ABOVE- i HAVE GIVEN A GENERAL OVERVIEW OF CHANGING OUT A DIRTY NOZZLE. NOW i GIVE key specifics to the proceedure.
the nozzle is 3 parts & unscrews from the end of the nozzle supply line.
BEFORE REMOVING THE NOZZLE NOTE CAREFULLY THE POSITION OF THE ELECTRODES IN RESPECT TO EACH ELECTRODE AND IN RESPECT TO THE CENTERLINE (to hole the oil sprays out of is the centerline) of the nozzle.
Electrode settings are 3 demensions. 1. the distance between the electrodes is 5/32” gap for a becket model AF oil burner.
2.The distance above the centerline of the nozzle is 7/16ths for a becket model af
3.The distance forward of the end of the nozzle is 1/16th “ for becket mod.AF using fo thru f31 heads and
1/8th” to 5/32 “ for af models using the F30 & f300 heads.
THREE THINGS SHOULD BE BECOMING APPARENT NOW. 1. MEASURE THE ELECTODE DEMEMSIONS BEFORE
REMOVING THE NOZZLE 2. GET or find THE OWNERS manuel for your model oil burner 3.BE CAREFULL NOT TO DISTURB THE ELECTRODES WHEN YOU CHANGE THE NOZZLE or you end up reseting them if you wish the oil burner to run.
Don’t be the bull in the china shop rather look & plan & consider before you act. The electrodes setting are held in place by only 1 screw and easly thrown a-cimbo- every which way. plan, in advance, for this to happen because it usually does. LAW OF MURPHY applies. (whatever can go wrong will,at the worst possible time)
there is a lot that can go wrong for the bulls of the china shop.
that means have the owners manual handy & do the job on a warm spring , summer, or fall day so you have time to get parts & info should the job not go just perfect.
Start by finding or ordering the owners manual first so electrode setting are available.
WHAT YOU
NEED TO KNOW ABOUT ELECTRODES.
electrodes too far into the oil flame/air pattern burn up the tips & need to be reset for now and replaced later this month.
electrodes too far away from the air/oil spray pattern wont ignite the fuel.
electrodes can be bent , in a pinch, to make them work & can be reground to a point, in a pinch , to get by with
for a while. be careful not to break the porcelean insulators when bending electrodes because the insulators are about $12.oo each & electrodes can run $12.oo to $30.00
They(electrodes) could probably be replaced in a pinch as a tempory fix by a steel gas welding rod or a heavy coat hanger
rod, but don’t rely on this as it is just a possible emergency measure. this assumes that the steel rod will fit inside the insulator & that the old electrode is not bonded to the insulator.
**
TO UNSCREW THE OIL SPRAY NOZZLE IT IS BEST TO USE A DEEP DRIVE SOCKET & RACHET WRENCH SO AS not to desturb the electrode settings & a open end wrench on the nozzle oil supply line.
once you crack the nozzle (like taking out a spark plug on the car) it unscrews like a spark plug, by hand.
the nozzle has a filter behind it, that unscrews counterclockwise by finger strength to break and can be cleaned with carb cleaner. be Very Carefull not to crush filter if you use pliers.
the nozzle filter is either screen mesh or soapstone. either one can be cleaned & reused, BUT BREAK EASY UNDER A PLIER.
Behind the nozzle filter you will see a screwdriver slot or a hex wrench slot to remove the needle jet from the nozzle. turn counterclockwise around 14 ft lbs to break. unscrew & clean the jet you removed & the hole you took it out of & the spray hole through the nozzle. one speck of dirt in the nozzle spray hole will make you do the job a second time to get it to work right. that why I told you to flush out the nozzle supply line also.
TO REMOVE TO NOZZLE ASSEMBLY FROM THE BURNER
First, insure the oil burner is off & no electricity is available to the oil burner. turn off hall way burner switch and fuse or breater that feeds oil burner.SAFETY FACTOR
2. hinge back spark transformer but removing 2 sheet metalor machine screws to get acess to the burner drawer/ blast tube area.
older burners make have a front door on the oil burner that has to be removed before the transformer can be
removed & 4 mounting screws make have to be removed to take off the transformer.
be advised that most oil burners are different & that is why you need to find or buy a new owners manual before you attempt to be your own oil burner repairman. The Burner INSTALLATION MANUAL should also be bought or found.
many oil burners require removal of the spark transformer before you can remove the nozzle assembly.
THE SPARK TRANSFORMER HOW TO REMOVE & TEST—-CAD CELL RELAYS—what they are,what they do
aside from the 4 mounting screws mentioned before, or removing 2 screws & hinging the transforer back as the becket does, the transformer has 2 wires that provide it electricity to the primary (110 volt ac) winding.
ac is alternating current (AC)————- the 2 wires are usually both black & it does not matter which way they are hooked up if you have a continious burn cad cell relay.
The cad cell relay allows the thermostat to turn the oil burner off & on by supplying or not suppling electricity to the oil burner motor & spark transformer, as called for by the thermostat.
with the continious burn cad cell relay, the burner motor & the spark transformer are wired (together) in parellel, so that when the motor runs the transformer sparks.
The cad cell relay refers to the cadimum cell that must see fire within 90 seconds or shuts off the electricity to the oil burner for safety. it has to be (push to reset ) before the oil burner will again run.
This is the safety that keeps the oil burner from spraying gallons of oil in to the fire box without the oil burning.
The cad cell has 2 wires that go to the relay and the cad cell has to have line of sight on the burner flame to see the flame. the cad cell is usually mounted inside the blast tube behind the electrodes so as to protect it from the heat by distance. The two wires must go on just as they came off so make a picture on a piece of paper and different color tape the wires to mark them.
HINT- ANY WIRES REMOVED- just cut 1 wire at a time , with diagnal cutters, in the middle & use wire nuts to reconnect the wires, different color tape & paper notes to rewire.
same color tape on both sides of where the cut in the wire will be.
Hint 2 — may need extra wire if wire ends up too short- use wire nuts to splice in extra length & insure wires are far from heat & away from moving parts. use twister seals to keep wire out of harms way.
wire nuts come in different sizes according to the thickness of the wires that they are to join. buy@ home depot.
(NOTE : i try 2 keep this easy 4 newbees, those fimilar with wiring,know to go into the juntion box & undo the wires taking appropiate notes on paper & color coding wires to idientfy them.)
The cad cell relay box has a (should have a)schematic wiring diagram but only electricians, ob repairmen, and electronic tecks ,like me can read them.
home depot sell easy to understand books to teach reading schmatic wiring diagrams.
The other kind of cad cell relay is the intermitant burn cad cell relay. it has 1 wire that goes to the oil burner motor and 1 wire that runs the spark transformer for only 3 minutes & then shuts off the electric to the transformer. the black wire from the motor goes to the motor terminal of the cad cell relay & the black wire
from the transformer goes to the transformer terminal of the cad cell relay.
the reason for this(the intermitant burn cad cell relay) is because transformers cost $80.00 – - 150.oo & last 20 to 30 years on intermitant run but only last 8 to 12 years on constant run, usually closer to 8 yrs.
constant run does not have any advantage except that the cad cell relay is cheaper to buy but eats up transformers early.
WHAT YOU SEE WHEN YOU LIFT UP OR REMOVE TRANSFORMER.
you will see the electrode assemble bolted on by 1 or 2 screws & clamps to the nozzle oil supply line which is 3/8 in copper pipe and the high voltage spark connectors to the secondary winding of the spark transformer which run at 10,000 volts ac. that is why I tell you make sure no electricity to oil burner before you start repairs.
The connectors between the electrodes & the transformer are usually coil springs that are bolted to the transformer secondary high voltage terminals and press against the electrodes when the trandformer is mounted in place but they could be clip on/ press on /or screw on /connectors on older burners.
You will also see the squiril cage fan blades & the coupling shaft to the OB-OP on 1 side & the coupling shaft to the OB motor on the other side
ATTENTION :: WHEN YOU GO to remove the small high pressure oil feed line 1/4 or 1/8 in dia. from the output of the oil pump to the input of the nozzle assembly, Note !!!! You must note the location of where the nozzle assemble comes out as there is a slot here for adjusting the nozzle assembly closer to the furnace or further away from the furnace & this affects the efficency of the oil burner and the life of the retention head.
MAKE SURE THAT YOU MARK WITH indellable magic marker what partr of the slot that the nozzle assembly come out of so that you can put it back in the same palce at the same setting.If you loose the adjustment, you can put it in the center of the slot and at a later date a oil burner man will charge you 150.oo to set it.
BE ADVISED that every thing has to go back in the same place as it was so as to maintain your ob settings.
Don’t mess with settings unelse you have to as oil burner guys have special equipment & training to get max efficency & long life out of your ob.
TESTING THE SPARK TRANSFORMER FOR PROPER FUNCTION
unscrew the transformer from the oil burner, cut the two wires from the transformer to the power junction box in the middle in order to leave enough wire to reconnect wire nuts to the wires and remove the transformer from the ob.
with transformer on the workshop test bench, hook up a ac cord (lamp cord with plug) or extension cord with female end cut off (leave enough wire to reconnect the female end back to the extension cord if you wish to restore your extension cord after the test.) to the 2 wires comming out of the transformer. Use wire nuts for the connections.
Find a long screwdriver with a heavy plastic or rubber handle capable of insulating you from 10,000 volts.
a 6 0r 10 in metal shank will do & almost any plastic or rubber handle screwdriver will insulate you from 10,000 volts as long as the plastic or rubber is not cracked ,broken or peeling. I would hesitate to use a wood handle screwdriver, if I had to I would wear rubber or plastic gloves with a wood handled screwdriver.
I have done this test often with a regular plastic handle screwdriver & never got shocked, just make sure there is no metal parts on the screwdriver handle.
WHAT TO DO TO TEST
plug in the transformer into the wall or an extension cord pluged into the wall. BEWARE THE SECONDARY TERMINALS OF THE TRANSFORMER AS THEY WILL HAVE 10,000 VOLTS ON THEM NOW.
Pull an electric arc using the screwdriver with the good plastic handle by touching one high voltage secondary winding terminal on to the steel shank of the screwdriver & sliding the screwdriver blade towards to other high voltage secondary winding terminal . when the blade gets about 1/2 inch a big fat juicy 1/8 inch thick fat spark will
sizzle and crackle across (not very loud, you can just about hear it whenyou quiet- ) but fat & juicy & lively,thick, spark & if the transformer is not humming loudly, you have a good serviceable transformer.
They 1/2 inch away is not a critical part of the test, the fat 1/8 inch thick spark is critical. If you have a spark that look like a thin diameter length of sewing thread, then the transformer is no good & ready for scrape yard.
a good spark transformer should not hum loudly, maybe just a little hum at most and give a good fat spark about 1/2 the diameter of a cigarette.
a big fat 1/8 in diameter spark is good.
a weak thin little spark like you get from a piezo cigarette lighter or a car spark plug means that the transformer is no good & needs replacement.
it time for christmas dinner now so I come back later and add more to this post.
It is cheapest to buy oil burner parts over the internet & have them shipped to you. A local plumbing shop wanted 130.oo for a intermintant burn cad cell relay and 90.oo for a continious cad cell relay that I found on the internet for 45.oo & 12.,oo ship/ & 30.oo with 10.oo ship.
replacement oB nozzles local are $6-$8 but I just clean the old ones & reuse them.
Sometimes you can get new oil pump filters or oil tank filters at home depot or lowes but it
is a seasonal thing
with them and maybe only in stock in aug or sept as that when most do their yearly tune ups.
more added later.