Oil Burner Acting Up. Help!

[mikelbeck]

Over the last few days my oil burner has been acting up.

First, it would run normally, but while it was running the flame would go out. Then it'd come right back on. It only seems to do this when it's hot, when it first starts up it runs fine until the temp gets up around 180 or so. Yesterday I replaced the oil filter (on the line that comes from the oil tank), bled the whole thing and got it fired up again.

Overnight, the burner shut down and this morning it was around 50 degrees in the house. I went down to check the burner, it was off and the temp was low. I hit the reset button and it fired right up, heated the house up. But after it while it shut down and didn't automatically restart even though the temp was lower than the thermostat settings. So today I changed the nozzle and the the filter on the motor.

It's still doing the same thing... once it heats up the flame goes out then comes right back on. And once it's warmed up, it shuts down and then doesn't automatically restart

Any ideas about what else to check?

[HayZee518]

yeah - open up the part that has the electric eye. remove the eye and clean the cell glass with a rag and replace it in its holder. if it still shuts down replace the cad cell. while you're at it check the electrode gap. it should be angled towards each other and slightly back from the nozzle. the transformer puts out about 18,000 volts and should jump a 3/8 " gap.

[mikelbeck]

Ok, checked that and it's nice and clean.

Before the flame went out, I cracked the bleeder valve on the fuel pump and some fuel came out, but then it stopped when the flame went out. It started up again a second later and the flame re-ignited. I checked the (new) fuel filter, it seems nice and clean and appears to be getting fuel without an issue. So I don't think there's any restriction in the fuel line itself, I think it may be the pump. Especially since it runs fine for a while, then dies after running for a few minutes... it pulls enough to keep going for a little while when it first starts, but may be too weak to pull enough fuel to keep it running. Does that make sense?

[HayZee518]

yes, the pump is a gear pump. it has very close tolerances between the ends and the rotors.

[mikelbeck]

Ok!

I changed the fuel pump and also a relief valve that was leaking. Primed and bled the system, it fired right up. Let it run through one cycle, towards the end of the cycle it started doing the same thing was doing before.

I opened up the line before the fuel filter and found that it was dry. I opened the fuel filter and it was only about half full. I opened up the line on the tank side and fuel came pouring out. So... I disconnected both ends of the fuel line, hooked up a line from my air compressor and let it rip. A whole bunch of crap came flying out the other end. Black sludge. So I guess my initial thought that there wasn't any restriction in the fuel line was wrong!

After doing that, I put the lines back together, bled it again and fired it up. It's been running fine ever since. Plus I've got a new fuel pump, all new filters, a new relief valve, etc...

[HayZee518]

I'm sure you will find all kinds of crap in the fuel tank. bugs, sludge, water etc. the outlet elbow from your tank has a short nipple inside the tank to allow the outlet to be ABOVE any water or crap that settles to the bottom of the tank. when you add fuel to the tank this sludge stirs up a bit and may go through the outlet into the filter component and may go past the filter as you found out. Glad you found out the problem!

[mikelbeck]

I'm sure you will find all kinds of crap in the fuel tank. bugs, sludge, water etc. the outlet elbow from your tank has a short nipple inside the tank to allow the outlet to be ABOVE any water or crap that settles to the bottom of the tank. when you add fuel to the tank this sludge stirs up a bit and may go through the outlet into the filter component and may go past the filter as you found out. Glad you found out the problem!

Since it's 32 degrees outside tonight, I'm glad I found the problem too!

When I was out picking up parts, I saw some additives that can be added to the oil tank to break up sludge. Do any of those actually work?

[HayZee518]

if you have a truck repair facility near you, go there and get a fuel additive. it will prevent the fuel from gelling and will emulsify any water so that it can be burned with the existing fuel - use a quart to 100 gallons.

[mikelbeck]

if you have a truck repair facility near you, go there and get a fuel additive. it will prevent the fuel from gelling and will emulsify any water so that it can be burned with the existing fuel - use a quart to 100 gallons.

I'll look into that, thanks.