Air leak in oil line
Hi everyone. I have been in the trade for about 26 years but have less exposure to oil then gas. And no experience with solving air leaks. At my aunts house my cousin and his plumber buddy changed her indoor oil tank. It was a steel tank, single pipe coming off the bottom and going into the concrete then popping up and feeding her HWH then furnace with a 3/8 line. They installed a new tank that looks like a Roth double wall tank but I never got the info on it. When they installed this tank the fed is now off the top, single pipe. The plumber used compression fittings and came out of the tank directly into an oil filter then connected to the existing oil line. There is a tee at the HWH and it continues about another 4 feet to the furnace. The HWH is getting all the air, which makes sense because it comes off the top of the tee. He needs to bleed the pump every 7-10 days or so. I figured the issue was the compression fittings so I changed them all to flares, bleed the line and left. But the issue continues to happen. I heard from an oil timer to put grease on the fittings and see when the air leak stops. I had my cousin put grease on all the new fittings but it is still happening.
What should be my next steps? I was thinking of replacing the entire oil line from inside the tank to the water heater. Coming out the top and following the rafters, dropping at the HWH with a firomatic valve and oil filter then connecting to the existing tee.
Thanks for your time guys/gals!
Comments
-
It's gotta be a leaky fitting somewhere. Perhaps at the filter. I'd prefer to see the filter indoors. If you can isolate each piece of equipment and check each burner with a vacuum gauge on the burner it will help with locating the vacuum leak. It would be best to find and fix the vacuum leak bit other options would be to convert the burners to a two pipe system or install a Tiger Loop as a band aid repair. There's nothing better than having a tight suction line with no leaks. Definitely check all flares again and take a good look at the filter. Make sure the vacuum level on the oil line isn't too high and causing cavitation. I'm sure some other more knowledgeable members will have some more great advice.
0 -
The entire tank, line and filter are indoors in basement. The oil tank is about 10 feet from the appliances. I would prefer to locate and fix the leak then put a cheap fix on it.
How would I use the vacuum gauge to determine there is an air leak?
Thank you for your reply.
0 -
Any pics?
You say they connected to the existing which runs under the slab? If so, no good. Run ALL new oil line. Coated. Sleeved if needed. All flare besides the compression sleeve into the tank if applicable. Seems silly it wasn't done when the tank was done.
What is used for the pick up out of the Roth? Is the 3/8 sleeved through a compression fitting and continues unbroken to near the bottom of the tank, OR are there connections at the top and bottom of the double tap bushing?
No problem with the filter at the tank as long as you can valve it off.
1 -
If everything is indoors then I don't have a problem with the filter at the tank. If you have a oil pump testing manifold you can connect it in series with the oil line to the burners. If you can close a valve by the oil filter then you can run the burner until it pulls a vacuum on the oil line. If the line holds a vacuum to one burner and not the other then you are one step closer to finding the source of the problem.
I definitely agree with HVACNUT. The line should be new coated copper with nothing under the slab. Copper reacts with concrete and will leak as a result. I just replaced an oil line last week because of this.
1 -
Fire-o-matic will fail, restrict flow, and cause a pump to cavitate. Probably when both units are running at the same time. I would not have the filter at the tank top. Put is down low to maximize the siphon.
1 -
I find that removing the fuel lines at the pump and plugging it with a flare plug, then placing a small amount of air pressure on the oil lines is a better way to locate air leaks.
I have always liked using the double tap tank bushing with the slip thru compression fitting in order to have a one piece fuel line from the bottom of the tank to the outside of the tank when the first fitting can be below the oil level in the tank…. A compression fitting in that case is not a leak issue, it is only a compression to hold the fuel line a fes inches off the bottom of the tank.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
2 -
I feel your pain with the overhead fuel line.
I have taken an illustration in an old book, and modified it to show the problem with overhead fuel line. In my previous post, I illustrated how to use the double tap duplex bushing with one slip-thru compression fitting, so the fuel line is one piece from the tank to the burner. In some jurisdictions you may not be able to do this because the AHJ wants a valve at the tank location. If you have this issue then there are at least another three locations for air leaks. The valve packing and the in and out connection of the valve. I have never had that problem, maybe the inspector in my area had no clue, or they just didn’t care.
Once you get to the burner where the oil filter and fir-o-matic valve is located, you have multiple leak locations, and the possibility to create one every time you replace the filter cartridge refill. I solve that problem with a tigerloop at the burner. Then I verify that there is no leak in mt fuel line piping by observing the oil in the tigerloop. If there are no foam or bubbles in the tigerloop when the burner is operating, then there is no air leak.
Here is the near burner setup
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
1 -
Thank you for responding. I talked with my cousin over the weekend. I am busy with replacing my parents AC unit so he had his plumber come back and run an entire new line. So we will see if the problem goes away. The plumber used a regular 2" tank bushing where the pipe is continuous through the compression fitting. However there is no firomatic valve at the filter. I will look to see if I have pictures. I do not remember if I took any.
0 -
What would be a small amount of pressure? 5 psi? The plumber did use a 2" tank bushing where the copper tube is just secured in place with a compression fitting. As I just mentioned in my other reply the plumber returned and ran a new line. But I am not sure exactly what it looks like and how he did it. My cousin said he ran it up to the rafters and down to the Tee at the HWH. I really like the idea of having one solid line coming out of the tank and running that to the oil filter at ground level near the first fuel burning appliance. I will have to see what the plumber did.
1 -
Thanks everyone for your help. If the oil filter is mounted at the tank when the line first comes out is a firomatic valve required? Because one was not there. I will add one if needed.
0 -
the pressure can be as low as a few ounce's per square inch. If this is done with no liquid in the line, all you need is enough pressure so that soap bubbles will show you where the air is leaking. If there is oil already in the line, then the pressure needs to be a little higher to cause the fuel to seep out of the leaking joint.
There is an oil deodorant powder that is the consistency of talcum powder that I spread on the suspected leaking joint by placing a small amount on my hand near the joint and blowing the dust onto the pipe joint. A leak will turn the powder a different shade where it is getting wet from the fuel leak.It is important to remove the fuel line from the fuel pump because 5 or 6 pounds of pressure may cause the pump seal to fail.
You can place a Capped or plugged compression fitting on the raw end of the copper tube at the bottom of the tank by removing the 2" fitting and carefully raising the tube out of the tank. You can plug the end at the fuel pump with a flare fitting with a Schraider valve and gauge so you can pump air pressure into the fuel line.
The first test would be to cap or plug the end of the line at the tank or turn valve off at the tank, then place a vacuum gauge at the fuel pump. Operate the pump until you get about 7 to 10 inches of vacuum. Shut off the pump and the vacuum should hold for at least 15 minute with less than 10% change in vacuum
If the vacuum does not hold there may be an air leak at the pump.
Perform the same test with the fuel plugged with no oil line connected and see if the vacuum holds. if the vacuum holds, the pump is good and the fuel line is suspect to be the source of the air leak. After this vacuum test shows the fuel line is the source. you can do the pressure test to find the leak.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
1 -
Why does it seam that two people have the same problem at the same time? I think I already answered this with some detail, then I find this
and wonder where all my other comments went. Then i realize that I'm posting on two different discussions. So i added thie link to to other and the other link here. This way both people having this problem have the benefit of the other thread
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
0 -
I don't understand people having constant oil line leak issues. Yes, they have always been a PITA to get air tight but you do what you gotta do.
Just learn how to cut and flare tubing and make up threaded fittings and you should be ok. I sense a Tiger Loop comment coming.
I don't know how we could have possibly made an oil burner run before TLs were invented which is probably only 25 years or so. Burners we have had for over 100 years
1 -
To pipe with a return back to the tank. Always recommended for lift conditions before TL. At least that is how I was taught.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
0 -
I agree, that is what we learned as well. Pump above oil level in tank is two pipe period. Avoid overhead lines if possible because they collect air. To me having a suction lift with one pipe is dubious at best. Overhead lines use two pipe. Skip the TL=more fittings=more leaks. The only time I would consider a TL is and outside tank to warm the oil. JMHO
0 -
I like the idea of only using one pipe from the tank to the burner. that reduces the flow rate from as high as 24 GPH (17 GPH on Suntec A pump gear sets) down to the firing rate (which is usually less than 10% of the gear set volume). And all those who are saying that "you need to make a leak proof oil line" are all hypocrites when they say it is OK to use 2 pipes in a lift situation. If they made their oil lines completely air leak free, there would be no reason for a 2 Pipe system, regardless of the tank to burner location difference.
Just Sayin’
The TL was invented to make every system better. Any issue that resulted in a problem with large volume thru the fuel line, can now be resolved with the TL. Saves part of its cost on installing a second line (both the tubing cost and the additional labor). Resolves cold oil thru a second pipe at the higher GPH rate as you indicated, and makes every system a self priming system. Saving on the mess and fuel waste associated with priming a fuel pump.
I have included a TL on every oil burner installation as part of the jib regardless of the tank to burner location, lift, or drop. It was a great selling feature, especially to those that were not on automatic delivery. Seems those fuel oil users ran out of oil on a regular basis, and needed to prime the burner more often than the customers on automatic delivery.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
0 -
If I had my way everything would be 2 pipe. Filter the oil while you run start with a clean tank and the tank will build less sludge because the oil is moving. I have yet to have anyone come up with an answer for that.
1 -
What I don't get is the fact that someone may recommend a new oil tank with a good reason, and the customer does not want to spend the $$$ on storing Thousands of dollars worth of product that will cost up to Hundreds of thousands of dollars to clean up after the $2000.00 tank fails. And that is from my 10 year old price book. I shutter to think about what a tank install might cost today!
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
0 -
About double or slightly more………………….thankfully most of them don't fail catastrophically. I worry about the underground tanks!!
0 -
If I had my way, there would be a government issued check sent to me every month for the rest of my life!
Edit… Never mind, they already do that.
If I had my way, oil would not have any sludge in it at all.
Edit… Never mind, that would put all the filter workers across the world out of a job.
If I had my way, heating your home would not be needed, because the outdoor temperature would always be 72°F so there would be no need for heating equipment. And that government check to start sooner in life.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
1 -
Thanks everyone. Sorry I have been absent here. Busy with work and family. Any-who my parents AC is done. Hopefully I can get to this issue soon and post some pics and information. This thread has been helpful with everyone sharing their experiences and ideas.
Since this is my Aunts house and I am not charging her I will take this time to mess around and learn. I will start with pulling a vacuum as Ed has mentioned. Then also use the powder he has shown.
I do find it interesting that this issue arose once the oil line was changed from being below the oil level (coming off the bottom of the tank) to know running up out of the top of the new tank. I cannot help but think a slight air leak may have always been there.
I need to think about this more.
- With the old tank, and the line coming off the bottom could the weight of the oil been keeping air out of a small existing leak that was just never noticed before.
- Now with the pump having to lift the oil up and out of the tank, if there is /was a leak at the tee, firomatic valve or the pump itself could it now be pulling in air.
Thanks again. I may not post for another week or two but I will update everyone. Thanks!
0 -
As you have discovered, overhead lines must be absolutely airtight. Ideally, in fact, there should be no fittings of any kind at least above the oil level in the tank — but that is usually not possible. Any joints must be made with the best craftsmanship!
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England2 -
You are absolutely correct. The weight of the oil that is pressing down on the bottom tank valve will always leak oil out of a small leak. It may not drip on the floor, but it will make an oil stain on the fittings. That oil stain will attract household dust. That dust will stick to the damp surface. Many service people think this is normal and don't much bother with it. Sometimes they think it was just left over from the last time the filter was changed or the valve packing is just a little loose. No big deal.
But when that flare fitting is placed at the top of the tank, then the leak becomes a vacuum leak, letting air in, ever so little. It may not be a problem in the colder months when there are longer on cycles and shorter time between off cycles. In the fringe months, the off cycles are longer allowing that air to build up and cause the pump to lose the prime.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
1
Categories
- All Categories
- 86.3K THE MAIN WALL
- 3.1K A-C, Heat Pumps & Refrigeration
- 53 Biomass
- 422 Carbon Monoxide Awareness
- 90 Chimneys & Flues
- 2K Domestic Hot Water
- 5.4K Gas Heating
- 100 Geothermal
- 156 Indoor-Air Quality
- 3.4K Oil Heating
- 63 Pipe Deterioration
- 917 Plumbing
- 6.1K Radiant Heating
- 381 Solar
- 14.9K Strictly Steam
- 3.3K Thermostats and Controls
- 54 Water Quality
- 41 Industry Classes
- 47 Job Opportunities
- 17 Recall Announcements