I have has several problems with my 35 year old, gulf burner, oil furnace. in the last heating season the blower motor fan limit switch and transforme/ignitor were all replaced. we had several mornings where we awoke to no heat. in any case after we had the unit serviced and fixed a new problem had suddenly arose. now- when the burner comes on u can smell oil 20 percent of the time. iot is a raw oil not burned. this problem started in april of last year. we are looking into buying anew furnace but would like to wait. today as i was sitting in my house i hear the burner cycle on which was folowed by a puff like sound. i believe this was it igniting approximently 3 seconds after the burner came on. we then smell the raw oil. i am wondering what can be wrong. we had proffessionals service it and they said evrything was fine. i am also wondering if i can smell oil in any case wouldn't that mean that my heat exchanger is cracked?

my questions are
1. is this delayed ignition
2. is my heat exchanger cracked
3. could the puff be something else or a sign of things to come?

i also have a problem well i think and that is that my burner cycles about 4 times an hour but only for like 3 minutes. in those three minutes the thermostat is satisfied and the burner shuts down before the fan even comes on. then about a minute later the fan will come on to distribute the heat.

 

The company that did the service, were they skilled with oil and had the equipement to test it?

Did they change the nozzel, filter, and screen?

 

Yes, it is late ignition. The causes can be many but some of the most common are: A weak ignition transformer (not likely-new last year), electrodes out of adjustment, too much air, & a dirty nozzle. If a pro serviced it this year, you should call them back & they should not charge you for a service call.
The short cycling is probably a thermostat adjustment. If you have a non digital thermostat, remove the cover & at the bottom or on one side there should be a small pointer with numbers on a dial or strip. This is the heat anticipator. They are often set at .2 to .4 set it to a higher number .6 to .8.

 

The people who serviced the furnace were also the ones who repaired it. I was not present when they serviced it, but I can tell you that they replaced the nozel, the oil filter, and screen. i would imagine that since they were qualified in oil equiptment that they would know how to adjust the electrodes and do the proper testing. In regard to the thermostat, it is a digital. I am starting to think the short cycling could be due to the fact that the heater is oversized. It has a 0.85 gph nozzel and this house is very small. I dont know about how many btu's that would be but I believe it is a lot. Yesterday the heat has started to smell more and more like oil. I am going to call my local gas company and see if I can get a gas line ran to my house. If so I would like to change over to natural gas heat. approximently what would a new gas fhh heater cost installed and the old oil equiptment taken away. I would also be interested in instaling central air.
My question are:1. Do you think I have a cracked heat exchanger considering that I can smell oil?
2. I do believe that i have delayed ignition, if the furnace never senses a problem i'e it never goes out on a safety lockout, will i be ok waiting a month to replace it?
3.Is it possible that since I am smelling oil more and more that the same problem has existed but the crack if any in the x changer has gotten bigger?
P.S. last winter I hit the reset button 3 times when the transformer had in fact went. when the company precision aire fixed it it originally made a huge rumble with a small fire inside the combustion chamber. During this fire the vents billowed smoke, this leeds me to believe that because the heat exchanger has heated so many times to its high limit it therefore cracked. My question is do you think this is a liable explanation to my problems today? if so i will be replacing the furnace quite soon. Could a heat exchanger crack also be the reason why the themostat is satisfied before the fan kicks in. this would be do to the heat and exhaust coming into the house producing heat.
Thank you in advance for any other help than the great help you have already provided. I know this is sloppy I have a hard time typing. if you have any question post them and i will reply asap. Thank you

 

Smoke out the vents in the house is not good. Unless there is a return in the basement or some oil got on the outside of the heat exchanger, there is a strong possibility the heat exchanger is cracked. If you even suspect it may be, get a qualified service person in there ASAP.

 

I will be getting some one in this saturday. it is going to be warm so i will make sure i don't use this untill it is checked.

 

I will be getting some one in this saturday. it is going to be warm so i will make sure i don't use this untill it is checked.
This would most likely explain why the house gets heated even though the furnace fan never comes on to circulate the air untill after the thermostat shuts down the burner.
thank you for your help.

 

Turned out to be a clogged supply line from the oil tank. I got intermittent pressure which made it very hard to diagnose, but the symptoms were just as you described. I had late and intermittent ignition and the house was always smelly and would fill with vapor (looks like smoke) while I was trying to figure out the problem. I disconnected the line from the pump to the nozzle and ran the furnace pump to watch the oil flow into a jar. There was a lot of air mixed in the oil coming out of the line and sometime oil would stop for a few seconds all together. This is where the puff comes from. Finally, I rigged up a temporary supply line and return line and ran it into a gas can with #2 fuel oil and the pressure was perfect and the heater fired just fine. Yours may not be a clogged line, but I would strongly suspect the oil pressure at the nozzle as the problem. I hope this helps.

 

jmarshmello
Turned out to be a clogged supply line from the oil tank. I got intermittent pressure which made it very hard to diagnose,
There was a lot of air mixed in the oil coming out of the line and sometime oil would stop for a few seconds all together.
Ill bet if you check that old oil line had pin holes in it or the filter had a air leak that is why you got the air . Not a clogged line

ED