Constantly bleeding air from oil line to start furnace
#1
03-31-18, 06:33 AM
Constantly bleeding air from oil line to start furnace
I have an Olsen fuel oil furnace with a Beckett AF-63 burner (age unknown). I've lived with this furnace for 13 years and have had numerous problems, mostly due to no fuel line filter. After having several technicians here I finally installed a new copper line and a General line filter. The unit was working fine for most of this winter when the "driveshaft" for the pump needed replaced. That was done by a service man.
About 10 days after that the unit began getting air in the line and needed bleeding to restart. At first, it would run for about five days before it needed bleeding again. This became more frequent until it wouldn't run one full day without bleeding. I replaced the pump screen and gasket, checked all the fittings in the line and looked for any crimps or visible damage to the line. The tank is outside and the line feeds out the top to the furnace about 5 feet below the bottom of the tank. The filter is about two feet from where the line enters the burner. The furnace worked properly for one week then we had a warm day where the unit didn't cycle on for maybe 12 hours. When the outside temp dropped the furnace came on as expected. At some point in the early morning hours the unit failed to fire up. I bled the unit and a lot of air came out.
It has ran through several cycles so far but I'm afraid the fundamental problem isn't solved and it's just a matter of time before I have to bleed it off again. I had a conversation with a tech and he asked me about the nozzle size. That just added to the confusion since the unit works fine except for this "air in the line" issue. I'm considering replacing the line with no filter or connections (I have a shut off valve about a foot from where the line exits the tank) just to see if that works.
Any help with this issue would be appreciated. I'm at wits end with this thing.
thanks
CDguy
About 10 days after that the unit began getting air in the line and needed bleeding to restart. At first, it would run for about five days before it needed bleeding again. This became more frequent until it wouldn't run one full day without bleeding. I replaced the pump screen and gasket, checked all the fittings in the line and looked for any crimps or visible damage to the line. The tank is outside and the line feeds out the top to the furnace about 5 feet below the bottom of the tank. The filter is about two feet from where the line enters the burner. The furnace worked properly for one week then we had a warm day where the unit didn't cycle on for maybe 12 hours. When the outside temp dropped the furnace came on as expected. At some point in the early morning hours the unit failed to fire up. I bled the unit and a lot of air came out.
It has ran through several cycles so far but I'm afraid the fundamental problem isn't solved and it's just a matter of time before I have to bleed it off again. I had a conversation with a tech and he asked me about the nozzle size. That just added to the confusion since the unit works fine except for this "air in the line" issue. I'm considering replacing the line with no filter or connections (I have a shut off valve about a foot from where the line exits the tank) just to see if that works.
Any help with this issue would be appreciated. I'm at wits end with this thing.
thanks
CDguy
#2
03-31-18, 06:42 AM
Member
You have a leak in the line. The line is under suction so you may not see oil leak out, but air will be drawn in.
I’m not sure why you’d want to run without a filter but as you’ve previously learned this can cause issues with the burner.
Don’t start randomly replacing things. Find the leak.
Or install a tiger loop. Which may not fully fix the problem.
I’m not sure why you’d want to run without a filter but as you’ve previously learned this can cause issues with the burner.
Don’t start randomly replacing things. Find the leak.
Or install a tiger loop. Which may not fully fix the problem.
#3
03-31-18, 07:13 AM
Thanks for your reply, roughneck77. Any suggestions on how to find where the air is being drawn in? I've checked all the fittings and they seem secure.
Also, another issue that baffled me when I was trying to figure out this problem. I removed the vent screw from the filter and nothing came out. No air, no oil. The tech that put in the driveshaft for the pump also changed the filter element. could this have something to do with the air problem?
Also, another issue that baffled me when I was trying to figure out this problem. I removed the vent screw from the filter and nothing came out. No air, no oil. The tech that put in the driveshaft for the pump also changed the filter element. could this have something to do with the air problem?
#4
03-31-18, 07:36 AM
Originally Posted by cdguy
". . . Also, another issue that baffled me when I was trying to figure out this problem. I removed the vent screw from the filter and nothing came out . . ."
#5
03-31-18, 08:25 AM
Yep with the plastic washer along with it. Just got a new filter element and some pipe thread sealant for fuel oil lines. Gonna try that and see what happens
#7
03-31-18, 08:30 AM
Originally Posted by Vermont
Do you have a "full" tank of oil . . . . I would think any leak that would suck air under suction would leak oil when idle ?
It seems to me the air is being pulled in when the unit is idle. During that time there isn't enough pressure on the line to force oil out anywhere. Could be the vacuum on the line when the unit is off is enough to draw in the air.
Last edited by Cdguy; 03-31-18 at 08:36 AM. Reason: additional comment
#8
03-31-18, 08:56 AM
C,
You said a tech replaced pump shaft. I'm guessing you meant the whole pump.
My thought is you have an air leak, which you know but shows up more when the burner is off for longer periods allowing the leak to break the vacuum and return the oil to the tank like filling a straw with liquid with your finger on top and then removing your finger to release the vacuum and draining the water. That sounds like what is happening. The oil is syphoning back to the tank due to the leak.
As was mentioned running without a filter is asking for trouble. When you put in the filter and line did you use compression or flair fittings.. You want to use only FLAIR fittings and make sure everything is tight.
You can install a vacuum gauge to see what is going on.
You mentioned an underground tank. Are you running your oil lower than the supply line is in the tank. They usually have the supply about 4" from the bottom of the tank. If the oil gets below that point you will suck in air even though you still have oil.
I wouldn't worry about the nozzle size at this point. It has nothing to do with your problem.
Hope this helps a little.
You said a tech replaced pump shaft. I'm guessing you meant the whole pump.
My thought is you have an air leak, which you know but shows up more when the burner is off for longer periods allowing the leak to break the vacuum and return the oil to the tank like filling a straw with liquid with your finger on top and then removing your finger to release the vacuum and draining the water. That sounds like what is happening. The oil is syphoning back to the tank due to the leak.
As was mentioned running without a filter is asking for trouble. When you put in the filter and line did you use compression or flair fittings.. You want to use only FLAIR fittings and make sure everything is tight.
You can install a vacuum gauge to see what is going on.
You mentioned an underground tank. Are you running your oil lower than the supply line is in the tank. They usually have the supply about 4" from the bottom of the tank. If the oil gets below that point you will suck in air even though you still have oil.
I wouldn't worry about the nozzle size at this point. It has nothing to do with your problem.
Hope this helps a little.
#9
03-31-18, 10:25 AM
You misunderstood. The tank is outside and sets about 3-4 feet above the pump, not buried.
All the fittings are flared, the shut-off valve, the filter and at the pump. It's all new this summer. I just disassembled the line and applied Permatex (for fuel lines) thread sealer to all the unions. Also, changed the filter cartridge and gaskets. I bled the line out and started the furnace. It's only been through one cycle so far. It's warm here today (Md) so I might have to up the therm periodically to see if it starts. I'll know better tonight when it cools down.
If I still have the air problem I'm going to get a new pump (Suntech A2VA-7116) and see if that's it. Is it possible the pump could have "weakened", for lack of a better term, to the point it won't hold the vacuum on the line?
The teck only replaced the "driveshaft". He showed me the old one and noted where the end that fits to the pump will "strip out" over time. He didn't recommend a new pump.
All the fittings are flared, the shut-off valve, the filter and at the pump. It's all new this summer. I just disassembled the line and applied Permatex (for fuel lines) thread sealer to all the unions. Also, changed the filter cartridge and gaskets. I bled the line out and started the furnace. It's only been through one cycle so far. It's warm here today (Md) so I might have to up the therm periodically to see if it starts. I'll know better tonight when it cools down.
If I still have the air problem I'm going to get a new pump (Suntech A2VA-7116) and see if that's it. Is it possible the pump could have "weakened", for lack of a better term, to the point it won't hold the vacuum on the line?
The teck only replaced the "driveshaft". He showed me the old one and noted where the end that fits to the pump will "strip out" over time. He didn't recommend a new pump.
Last edited by Cdguy; 03-31-18 at 10:27 AM. Reason: P.S.
#10
03-31-18, 03:19 PM
Very possible for the pump gears to be worn and lose the vacuum. Never heard of changing just the pump shaft. Guess it depends what part of the country you're in.
I did misunderstand, thought you had an underground tank. A vacuum gauge could tell you if you're loosing your prime.
I think that's a good idea to change the pump if you are sure everything else is tight and secure. The pump is the last link and I don't know how much I would trust a shaft change. What made him change the shaft in the first place.
Usually it's the gears or seal that goes.
I did misunderstand, thought you had an underground tank. A vacuum gauge could tell you if you're loosing your prime.
I think that's a good idea to change the pump if you are sure everything else is tight and secure. The pump is the last link and I don't know how much I would trust a shaft change. What made him change the shaft in the first place.
Usually it's the gears or seal that goes.
#11
03-31-18, 04:04 PM
Member
I think by “driveshaft”, the OP means the pump coupler in between the pump and motor shafts. A common part that wears and requires replacement.
#13
03-31-18, 06:27 PM
this whole issue began when I thought I had run out of fuel because when I installed the new fuel line I kept it up about 4"s from the bottom and I thought my guage may be off. It said 1/4 but I wasn't sure so I called my supplier and told them I think I"m out of fuel. They sent a tech with 10 gals and when he attempted a restart he couldn't get any fuel up the line. He hooked a pump up to the line and drew fuel to the pump. It still wouldn't start. That's when he pulled the motor and found the pump coupler was badly worn. When he replaced it the furnace started right up. It was about 10-12 days later when this "air" issue started.
The unit has been cycling ok since I sealed the threads and changed the filter element. Hopefully, it will continue to work as expected. Darned thing tends to have a proclivity for shutting down in the wee hours so I'll see if I can get through the night and beyond. If it shuts down again I'll replace the pump asap. Aside from that, I'm out of options other than calling the tech back for a professional assessment.
The unit has been cycling ok since I sealed the threads and changed the filter element. Hopefully, it will continue to work as expected. Darned thing tends to have a proclivity for shutting down in the wee hours so I'll see if I can get through the night and beyond. If it shuts down again I'll replace the pump asap. Aside from that, I'm out of options other than calling the tech back for a professional assessment.
#15
04-01-18, 02:52 AM
You've replaced the Line and the Filter and the Coupling . . . . how about the Fuel Strainer inside the Pump ?
Clean it, or replace it BEFORE changing the entire Pump; it's made of a rigid micro fabric and an old toothbrush and a solvent works well. It collects a lot of paraffin and crud from the tank that manages to make it through the Filter.
Clean it, or replace it BEFORE changing the entire Pump; it's made of a rigid micro fabric and an old toothbrush and a solvent works well. It collects a lot of paraffin and crud from the tank that manages to make it through the Filter.
#17
04-01-18, 05:01 AM
Originally Posted by Vermont
You've replaced the Line and the Filter and the Coupling . . . . how about the Fuel Strainer inside the Pump ?
Clean it, or replace it BEFORE changing the entire Pump; it's made of a rigid micro fabric and an old toothbrush and a solvent works well. It collects a lot of paraffin and crud from the tank that manages to make it through the Filter.
Clean it, or replace it BEFORE changing the entire Pump; it's made of a rigid micro fabric and an old toothbrush and a solvent works well. It collects a lot of paraffin and crud from the tank that manages to make it through the Filter.
The furnace ran through the night so I'm hopeful.
Happy Easter, Vermont and roughneck77. I really appreciate your willingness to help me out with all this.
#18
04-01-18, 05:22 AM
Member
Do not change the pump just to change the pump. It’s things like this that derail many a DIYer, as then they’ve spent a lot of money by throwing parts at the problem and still have a unit that doesn’t work.
You can buy a tank fitting, and put an adaptor fitting in it to accept an air hose. Then you can plug the supply line by the pump and lightly pressurize the system (very lightly, ~5 psi). This positive pressure should show you where any leaks are.
I’d also want gauges connected to the system to know what suction and nozzle pressure were. I use these-
https://www.amazon.com/gp/aw/d/B00EI...vuL&ref=plSrch
You can buy a tank fitting, and put an adaptor fitting in it to accept an air hose. Then you can plug the supply line by the pump and lightly pressurize the system (very lightly, ~5 psi). This positive pressure should show you where any leaks are.
I’d also want gauges connected to the system to know what suction and nozzle pressure were. I use these-
https://www.amazon.com/gp/aw/d/B00EI...vuL&ref=plSrch
#19
04-01-18, 05:49 AM
Originally Posted by roughneck77
Do not change the pump just to change the pump. It’s things like this that derail many a DIYer, as then they’ve spent a lot of money by throwing parts at the problem and still have a unit that doesn’t work.
You can buy a tank fitting, and put an adaptor fitting in it to accept an air hose. Then you can plug the supply line by the pump and lightly pressurize the system (very lightly, ~5 psi). This positive pressure should show you where any leaks are.
I’d also want gauges connected to the system to know what suction and nozzle pressure were. I use these-
https://www.amazon.com/gp/aw/d/B00EI...vuL&ref=plSrch
You can buy a tank fitting, and put an adaptor fitting in it to accept an air hose. Then you can plug the supply line by the pump and lightly pressurize the system (very lightly, ~5 psi). This positive pressure should show you where any leaks are.
I’d also want gauges connected to the system to know what suction and nozzle pressure were. I use these-
https://www.amazon.com/gp/aw/d/B00EI...vuL&ref=plSrch
#20
04-01-18, 09:20 AM
Member
In that case I’d let your oil guy do more troubleshooting. It’s easy to replace parts and get nowhere with the money spent on them.
Best to diagnose first then buy only the parts you need.
DIY or not, I can’t encourage anyone to blindly replace parts. I wouldn’t be happy doing work like that and neither would my customers.
Best to diagnose first then buy only the parts you need.
DIY or not, I can’t encourage anyone to blindly replace parts. I wouldn’t be happy doing work like that and neither would my customers.
#21
04-01-18, 10:04 AM
Think Ahead, Avoid Heating Problems on Cold Winter Night.
This thread reflects a common chain of fuel issues. Instead of focusing on motor coupling as smoking gun think of things starting from oil tank. The pump/coupling failure may have resulted from lack of oil to pump.
1. A good way to monitor and diagnose fuel issues is with $6.00 vacuum gauge in line between pump and filter.
https://www.supplyhouse.com/Westwood...-Hg-1-8-NPT-LM
2. Install a cartridge type fuel filter before the pump. Vacuum gauge indicates filter status. When it rises to 12 hg replace filter. Replacing filters annually is wishful thinking.
3. Reduce fuel oil related issues using$10 oil treatment on a regular basis See post #9 in:
Oil Boiler falls below low set point overnight
Here is link to burner motor couplings. Typically package comes with adapters for several shaft sizes. For less than $3.00 keep a spare.
https://www.supplyhouse.com/sh/contr...oupling%202454
1. A good way to monitor and diagnose fuel issues is with $6.00 vacuum gauge in line between pump and filter.
https://www.supplyhouse.com/Westwood...-Hg-1-8-NPT-LM
2. Install a cartridge type fuel filter before the pump. Vacuum gauge indicates filter status. When it rises to 12 hg replace filter. Replacing filters annually is wishful thinking.
3. Reduce fuel oil related issues using$10 oil treatment on a regular basis See post #9 in:
Oil Boiler falls below low set point overnight
Here is link to burner motor couplings. Typically package comes with adapters for several shaft sizes. For less than $3.00 keep a spare.
https://www.supplyhouse.com/sh/contr...oupling%202454
#22
04-03-18, 04:53 AM
Originally Posted by Vermont
You've replaced the Line and the Filter and the Coupling . . . . how about the Fuel Strainer inside the Pump ?
Clean it, or replace it BEFORE changing the entire Pump; it's made of a rigid micro fabric and an old toothbrush and a solvent works well. It collects a lot of paraffin and crud from the tank that manages to make it through the Filter.
Clean it, or replace it BEFORE changing the entire Pump; it's made of a rigid micro fabric and an old toothbrush and a solvent works well. It collects a lot of paraffin and crud from the tank that manages to make it through the Filter.
I want to thank all you guys for your input. I have to admit I'm one of those guys who knows just enough to get into deep trouble, sometimes. I've certainly learned quite a bit about this particular problem but have also learned there's more to it than just replacing a couple moving parts and an old fuel line when it comes to having a safe and efficient furnace. Thanks again.
#23
04-04-18, 02:59 PM
Cdguy: It appears there was a point in the line where air was getting sucked in while the unit was idle. (Never did find any evidence of fuel leaking out of the line.)
Air leak is obiously at high point on line and oil drains away from leak point when burner is not pumping .
This is suction line with negative pressure. There is not need for expensive gauge sets.
First visually inspect the line where possible. Look for damage or stress points.
Every few years line from my outside tank has too be blown out. Made life easier putting a tee in line before filter with 1/4” ball valves and pipe plug in third port. Can shut valve to filter, remove plug and blow out line to tank.
Port can be used for very low pressure air to check for leaks.
Setup is also helpful when changing filter to shut off oil reducing mess.
Last edited by doughess; 04-04-18 at 03:20 PM.
