Heating Oil Pipe Leak Diagnostic FAQs

Find & fix oil line leaks
Foaming heating oil
Oil burner fuel line repair
Oil line leak shuts down oil burner

Detect Air Leaks in Heating Oil Piping - FAQs

Tip: See our diagnosis and repair details at OIL BURNER FUEL UNIT AIR BLEED PROCEDURE

How can we tell if there is air in the heating oil lines?

We have a oil burning heater that won't fire up because we think there is air in the lines ? On 2019-11-09 by Anonymous

Reply by (mod) -

Anon:

If there is air in the heating oil lines it will be due to a leak either in the oil piping (tank to burner), at the oil filter, or at the oil burner's fuel unit on its suction side.

A leak on the oil burner's high pressure outlet connections or tubing will of course leak oil out when the fuel unit is running.

There is of course a procedure to use the air bleeder screw to purge air from the oil burner and piping near the burner - for safety you ought to have your heating service tech go through that for you.

You might have air in the piping or oil filter canister and fuel unit IF you ran the oil tank dry and then got a new oil delivery.

Otherwise the danger is that there is an air leak in the oil piping; in that case even if you purge the air the problem will recur, and worse, sucking air into the oil piping while the burner is running will ultimately lead to poor oil burner start-ups and possibly a puffback explosion.

So if that's the case your tech will

1. Observe that there's an air leak in piping by monitoring the vacuum level on the oil supply side

See OIL LINE VACUUM & PRESSURE TESTS

2. Find and fix the leak by observation (wet spots on the line or simply checking and tightening fittings)

See OIL BURNER FUEL UNIT AIR BLEED PROCEDURE

3. Clean and adjust the oil burner if needed

Why do I have to repeatedly bleed air from my oil burner fuel line?

I have to keep bleeding my fuel line it runs fine but if it sits idol for a hour I have to bleed it again? checked for leaks didn't fine any, new filter, so any ideas? On 2016-03-25 by paul

by (mod) - Find the air leak: you can repair a section of flexible copper tubing or piping for your oil burner fuel line.

I suspect there is an air leak somewhere in your oil piping system. You need to find and fix the air leak in the line

Yes Paul you can repair a section of flexible copper tubing or piping for your oil burner fuel line. Use two flare fittings.

But take care: a proper flare fitting requires some attention to detail. You'll need a cutting tool to cut the tubing, a pair of reamers to remove the internal and external tubing end burring that occurs during cutting, and a tubing flaring tool plus some instruction in how to use it.

Making an inadequate or poorly-made flare connection has results ranging from troublesome (oil leaks out, air leaks in, loss of heat) to dangerous (puffback explosion due to chronic air leaks). The flared end of the tubing has to be of proper size for the flare fittings - too big and it won't fit in the fitting, too small and it may leak.

See GAS LEAK DETECTION, LP / NG or some photos and examples of copper flare fitting snafus.

Do Air Bleeder Valves on oil lines "go bad" & cause the oil burner to malfunction?

Do bleed valves go bad

Open bleed valve bleed some; while closing valve I noticed an oil drip. Boiler runs to temperature on thermostat shuts down again. 2 year old Beckett oil burner.

Beckett oil furnace red light blinking pushed button bleed valve keeps shutting down On 2021-03-17 by Ron

by (mod) - air bleeder valves on hot water heat piping don't cause oil burner failure

@Ron,

An air bleeder valve assembly is simply a threaded device, tapered to seal that opens and closes a port on the oil burner fuel unit.

I suppose it could be damaged by cross-threading so that it leaked and dripped oil.

but other than that it doesn't go bad in that the bleeder valve itself would not be the cause of oil burner going off on reset.

Watch out: in comparison, an air leak anywhere in the oil piping or any other cause of a bad flame could infect because of the burner to go off on safety.

Foaming Oil = Air Leak in Oil Lines

Loss of vacuum in oil lines, burner runs, dies, oil is foamy

Hello there. I'm hoping to get some insight into an issue I'm having with my oil burning furnace.

So the problem I'm having is loss of vacuum in my oil line. I have a single line system and it is connected in the following way:

Starting at the tank outside the line comes out the top about 4 feet up and turns 90 degrees to pass through the exterior wall into our washroom where the furnace is located. So the line that is inside the room runs at the same height for about 3 more feet. It the passes through a shutoff valve which is directly connected to an old filter housing.

Then the line runs about 1 more foot and drops down about 3 feet into a trap curve. From there it runs about 7 more feet at a slow decline until it is pretty much sitting on the ground which then turns up for about a foot and a half that connects to the pump.

Just to add to the info available when we moved into this house the owners believed that the oil tank was about half full of oil.

This was in the summer so we didn't really worry about it to much. Well now that its winter and we have started using it, it turns out that there was a thin layer of oil but everything else bellow that was water

. I have since replaced the copper lines (which is the run I previously mentioned), the fittings, the flaring on the pipes and the oil filter insert (Not the actual canister). I have also pumped the tank and removed the water from it. I have completely cleaned out the pump of all junk and it is spotless now. I replaced the air filters recently as well.

So here is where it gets tricky. Because this was a surprise expense we don't have the upfront cash to get the tank filled.

So what I did was put a disconnect in the horizontal run before the line goes into the exterior wall. That way I can hook up a line going into a smaller 5 gallon tank that I can put off-road diesel in to hold us over until next year. I know it’s not economical but it’s all I can do right now.

Now... the problem. Running the unit seems to be working just fine. I prime the system, close up the bleed valve and start it up. Flame on, works great every single time but I have to prime it... every... single... time...

Any time the system shuts down because the temperature is reached in the home it sits for about 30 min to an hour.

Then when it's time to come back on the line has created a very large air pocket. When I go to purge the line after this happens I get about 2 seconds of oil, then it quickly becomes frothy for the next 2 seconds, then it just dies out for about 3 seconds. Then it finally catches the oil and froths for about 5 seconds and then turns to a good stream of oil.

Once the unit stops purging I close the bleed valve and start it up and it works just fine.

So after this happened a few times I decided to test something out. I ran the heat and when it finally got to the temperature I wanted I cut the heat off and then closed the shut off valve that sits before the oil filter. I figured I could find out if there was a leak in the filter if I let it sit for a few hours.

So I went back out to my shutoff valve. Brought up my remote thermostat app on my phone and turned the heat on. I opened the shutoff valve right before I started my heat up and low and behold the furnace lit right up. I didn't have to purge it at all.

So... with all that being said, does anyone have any ideas as to where my problem could be?

I just ordered a newer oil filter since that is a pretty cheap route to look into. Would fuel being pulled from a small tank pose this problem?

I would think that as long as the pipe stays submerged in the oil it should create a vacuum and not allow the oil to back flow into the oil tank.

Any advice you can provide is greatly appreciated. On 2017-12-28 by Jose

by (mod) - signs of an air leak in oil piping

Most likely there is an air leak somewhere in your oil line piping

Oil Line Piping Repair & Connection FAQs

How can I replace just a section of damaged copper oil burner pipe line?

I discovered a kink in the soft copper line outside the house between the tank and where the line enters the house. Can I splice the line and if so with what type of fitting? If not, it would involve replacing 30 feet of copper unless other materials can be used. Thank you. On 2016-03-24 7 by Roy B

Reply by (mod)

You can cut a damaged section of copper oil piping and using a flaring tool and flare fittings, splice in a new replacement section.

Details are at COPPER FLARE CONNECTIONS 

How do I connect the copper oil line to the oil burner pump?

Can i fit copper pipe direct to burner pump On 2017-01-10 by Henry

by (mod) - can I fit copper pipe direct to burner pump?

No you will need a flare fitting to connect copper to a threaded fitting that connects to the fuel unit and you should also install an oil filter and a fire-safety valve at the burner.

How to Fix Fuel Oil Leak at intake pipe (suction line)

My fuel oil furnace is leaking gel oil right at the in-take pipe. Assume their air in the line. How do I fix this? On 2016-11-22 by Megan

by (mod) -

you either have to disassemble and remake the connection with pipe sealant rated for use on oil piping systems, or if the leak is minor you might make a temporary fix by cleaning the surfaces and applying an epoxy sealant

 

Heating Oil Line Life Expectancy

How long do brass pipes (oil lines) last before there's corrosion ? On 2016-10-04 by David

by (mod) - how long do brass oil pipes last?

Paul:

I think you mean copper oil piping as that's far more common than brass.

Copper oil lines can easily last 50 years or longer if the piping is properly installed and protected.

Abrasion from vibration, failure to protect the piping from mechanical damage, burial directly in concrete, burial in corrosive soils can of course mean a shorter life.

Watch out: oil line clogging from sludge can often be cleared but if not, that too can mean the end of an oil burners pipeline.

How to seal off an unused copper oil line

I have a 2 line system one of the line leaking.

I can setup as a 1-line oil delilvery system with no problem but I need to seal off the leaking one !

I was wondering if there is anything I can put into that line that would not break down with the fuel and save me from having to dig up the second line caulking ? (July 6, 2014) lee

Reply: heating oil line abandonment procedure

Lee,

Watch out: I've seen unused oil lines that were simply bent over and crimped using gooseneck or other high pressure pliers but in my OPINION that is not a reliable closure as there may still be air leaks in or oil leaks out of such an oil line if either end of it is attached to an oil burner or to an oil tank.

Best would be to remove the unused oil line completely and where necessary screw in a brass plug into the fittings where the oil line was removed (from a fuel unit or at the oil tank).

To close off a copper oil line without creating a future mess the best approach is to simply buy a flare fitting and a flare-threaded plug that will screw into the fitting.

Using a flaring tool, install the flare collar, flare the tubing end, install the flare fitting and screw the collar tight; then screw the flare threaded plug into the flare fitting.

All of these few parts (and the tool if necessary) can be obtained at a local plumbing supplier.

You simply need to measure the OD of your oil line so that you buy the correct flare fittings - 3/8" or 1/2" for example.

Oil Burner Trips Off Due to Oil Line Leaks

Replaced oil burner parts, there are oil leaks and furnace won't keep running

Installed new oil furnace & Beckett Burner. Have replaced bypass plug, oil pump, primary control, removed compression fittings, and put device on burner to adjust drip rate.

Furnace has run no more than a day at a time, 2 oil leaks from burner. Burner is " new technology" type. What next?

by (mod) re: drips at the oil burner sounds like an oil line leak

Mike:

Replaced bypass plug: what's up. Are you using the internal bypass or is this a 2-line oil supply system? Be sure you've got that right.

I'm unclear on what device you're installing on burner to adjust a drip rate and why that's needed.

An oil burner should never "drip" - if there's a drip - say after the burner shuts down then there's a problem to find and fix such as an air leak in oil piping or a fuel unit that's not shutting off cleanly.

Oil leaks at the burner or in piping or at the filter absolutely must be found and fixed - air leaking into the system when the fuel unit is operating will cause sooting, improper burner operation, and shut down on safety-reset.

See the oil burner fuel line leak troubleshooting and repair guide

at OIL SUPPLY LINE PIPING LEAKS 

Watch out: don't keep pressing the reset button or you risk an OIL BURNER PUFFBACK explosion (search InspectApedia for that phrase to read more)