Unfortunately there are NO , absolutely NO , oil furnace technicians left around
here so I'm on my own and "learning" as I go.Everything is propane or natural gas.

Here's my problem. The furnace will run just fine for about 30 minutes then
kicks out the control safety switch. If I go down and restart (letting the
lock out safety switch cool for about 10 minutes) , it will run for about 15
minutes. If I leave it for 1/2 hour so so , it will once again run for about
1/2 hr then lock out.

I've replaced the nozzle , checked the electrode gaps (thanks UTube for
showing me the way ) , changed the line filter at the fuel tank , the tank
was recently filled (I noticed quit a bit of sludge in the tank when I
drained about 1/2 gal to make sure the fuel was flowing out of the tank so I
jacked it up some more and have a supply of filters on hand to change
periodically) .

I'm thinking :
a) possible screen at fuel pump clogged and only allowing so much fuel
in.Hence the varying run times.
b) defective LED though it does fire and run 1/2 hour or so.
c} defective Honeywell control unit but why would the reset heat up
gradually over a 1/2 hour period to the point it locks out.

Any assistance (ie which should I check/replace first) would be appreciated.
BTW I don't have access to a pressure gauge and not really too sure how to
measure Ohms for the LED. Replace is my easiest option.

 

Let's start with the full model number of the Honeywell control.

Then some pictures of the installation. Pictures need to be from a far enough distance (or wide angle) to see how different parts are connected. If I need close-ups I'll ask. Pictures need to be in focus and well lit. dim, fuzzy pictures of are no use. Best is to take high definition pictures and host them on a site such as photobucket or imgur and post the public URLs here.

Next, is the fuel tank above the level of the burner? Are there any fittings between the tank and the burner that are not of the flare style? When was the last burner service and do you have a detailed report of what was done? About how old is the tank? What is the nominal temperature in the area of the tank? Do you have a single tube or two-tube connection between the tank and the burner? What kind and specification filter do you have at the tank and do you have an additional filter at the burner?

When you write "LED" do you mean the flame sensor? If yes, the sensor is NOT an LED but a cadmium sulfide photoresistor cell. Testing it with an ohmmeter is problematic at best and direct replacement is the superior test, they aren't all that expensive.

 

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Ummm. Are cheap oil prices a bargain compared to natural gas these days?


Unfortunately, your comment above suggests that your days of burning oil need to end. Oil furnaces NEED annual maintenance, and they are going to need repairs, especially old ones.

If you can't get the skilled maintenance and repair you need, it's time to consider moving on, in my opinion.


Where are you buying your oil? Most oil dealers provide repair services as part of their service.

 

The joy of oil is you only pay for what you use. Natural gas runs by but you end up paying almost $1,000+ / year just for the joy (they call it admin and line maintenance) of having it hooked up (plus your usage). We're looking at propane but that's a spring/summer job (tank installation/trenching line etc.). Right now we're just trying to nurse maid/bandage fix our old oil burner.

 

Fuel tank is above burner , all line fittings are flared , furnace is over 65 years old , fuel tank..about 50 years old. The only fittings between the furnace and fuel tank is an inline filter. Filter is outside on tank (about 3 feet from house). It's a single line feed and we buy our fuel from UFA (Ultra Low Sulpher) winter grade..gels at -45C. Nominal temperature during winter would be in the -15C to -20C and yes , I accidentaly called the cell an LED.
The burner was last service about 3 years ago (other than what I've done such as change nozzle and checked the gap of the electrodes). It was cleaned , nozzle replaced , electrodes set , pump and motor checked and told all was good.(BTW - that was the last of the oil techs I could find out here and he moved back to Nova Scotia).
Photo Cell about $30 and Honeywell control about $70. Just want to try and nurse the old gal through the winter then we're going to look at propane.
Also , the furnace is basically supplemental as we use a lot of wood in a wood heater.
It's not a problem for me to replace the cell or control unit IF they're likely to be the source of the problem.
Txs

 

I would change the pump strainer and gasket if you know you have one. Cheapest option.Could check gravity thru the line by briefly opening the valve while you have it apart.

 

Txs..I'll try that. Pretty sure there's a screen in there but I'll get the pump info and double check on net before a take the cover at the back off.

 

Oil pumps made by Sundstrand, Riello, and Danfoss (there are more for sure) have cleanable/replaceable screens inside of them. Webster pumps do not. I wholeheartedly believe that to be your problem.
Oil heats best btw

 

Well I cleaned the screen and made sure the oil was flowing freely form the tank..problem persists...runs about 10 minutes then locks out.

Completely baffled as to what to try next. The only things I can think of is replacing the photo cell then the Honeywell controller. can;t think of anything else.