Beckett Pump losing prime

cwaz

Good morning all, I'm hoping to get a little holiday help here as this one's got me stumped. My Weil McLain has been running like a champ since September and all of a sudden I started having issues yesterday.
A quick synopsis: thermostat calls for heat, boiler kicks on, lock out button pops (as some point over night during the set back), I open the bleed valve for a few seconds, close it and she fires right up. After this process she will fire back up a as needed as the vaporstat takes control until the thermostat is satisfied. The priming issue only appears to occur during long periods of the boiler being shut off.
Any thoughts on why I'm losing prime?? I checked for leaks around the connections and valves but can't find any.
Luckily I've trained my wife how to prime the beast, might need to extend that training to my teenage girls lol. Thanks in advance! And Happy Thanksgiving to everyone.

Bob Bona_4

Describe the oil delivery piping.

cwaz

Bare, soft copper tubing from two stand alone Roth tanks, travels approximately 16" up from the top of the tanks to the bottom of the floor joists, travels parallel with the floor approximately 4 feet, takes a 90 degree turn, continues along the joists, drops 6' to the floor via another 90 degree bend, once at floor leve it takes another 90 degree bend on the surface of the cement floor ( a short portion runs through mortar "attaching" it to the side of the boiler slab), then takes another 90 degree bend up to the filter inlet.
The portion running through the mortar is showing signs of corrosion, the copper is turning green, could it be there is a small leak there that is allowing air into the line during the long periods of inactivity?

Bob Bona_4

Any lift scenario demands an oil deareator. The issue only exacerbates as the tank level drops. You may or may not also have a minute air leak. Some checking with a vacuum gauge will reveal this.

Providing the system is tight, your best insurance is a TigerLoop Ultra deareator.

Robert O'Brien

Ridgid tubing in Roth?

EBEBRATT-Ed

If your loosing your prime you have a leak plain and simple. Find it and fix it. Disconnect the piping and pressure test it. A tiger loop is just more unnecessary fittings, restrictions and places for a leak. The other fix is to make it a two pipe system as it will prime itself. (no one will agree with this)

EBEBRATT-Ed

true. but a leak in he suction line below the oil level will send the oil to north korea

Brewbeer

Oil lines buried in concrete can corrode and leak if the oil line isn't sleeved or coated. Consider by-passing the section beneath the concrete.

Robert O'Brien

Two ways this happens without an air leak.
1. The oil is degassing under vacuum, as little as 4-5" can cause this
2. Overhead oil lines are best avoided if possible, tiny air bubbles coalesce over a period of time into one large bubble in the horizontal portion of oil line. Even Tigerloops can be overwhelmed by this sudden appearance of a large quantity of air. Power bleeding can resolve this if it is due to the line not being purged of air.
Steps to power bleed
Bleed the system in the conventional manner
- Close the valve at the tank
- With the bleeder valve open, run the pump until a good vacuum develops
- Open the tank valve
- Repeat this process

Robert O'Brien

"An oil burner that is supplied by an overhead oil line can develop unusual vacuum conditions over
time. When setting up such a burner, the objective is to totally fill the overhead line so that there
is a true siphon. However, if the overhead line is not totally purged, as the burner runs (and it
could be months later) the vacuum can keep increasing until the pump is starved.
As explained by Bruce Marshall of Suntec Pumps, with an overhead oil supply line on a single line
system, it is not enough to just run a pump for a while until the bubbles stop coming out. The
overhead portion may remain partially filled with air. In fact, the tubing may have filled with oil
only as much as is needed to supply the pump and this means there could be a lot of air.
The problem of excessive vacuum develops because, as the burner runs, microscopic air bubbles
can escape from the oil, increasing the amount of air in the overhead portion of the supply line. It
may take several months, but the available spaceî can be so small that vacuum readings can be
excessive"

Bob Bona_4

Thank you Robert for putting it out there. In a lift situation, the pump runs the ragged edge on one pipe. Like Robert said, the oil becomes "stretched", foaming occurs, then pump cavitation, then game over.

Tiger Loop devices should be SOP in any lift jobs. It is NOT a band aid or a means to cover over defective joints.

EBEBRATT-Ed

What Bruce Marshall said is true however this will not happen if the oil line is sized correctly , happens with oversized lines. Hooked up one pipe an overhead line is only moving nozzle capacity .50, .75/hr is not much flow and I suppose you could collect bubbles. On two pipe your moving pump capacity say 7gph and you will have no such problem and will not need a tiger loop if the lines are 100% tight.

Pumps and tanks stay cleaner with 2 pipe as you are constantly moving, pumping and filtering oil. Low flow lets sludge settle out.

JMHO after 42 years and goes against conventional wisdom.

Oilmon

If every joint is tight, AND all air has been purged from the fuel supply run, the likely point of entrance of small amounts of air would be the pump seal itself. I have solved many single pipe, topline oil feed loss-of-prime issues with a fuel unit changeout. Even though there is not any evidence of FUEL leakage from the seal, they can and do sometimes allow small amounts of air in around the shaft, which accumulates inside the pump body until cavitation and loss of pumping ability ensue.
That being said, however, a Tigerloop is a permanent solution to the problem , albeit a bit more costly.

Robert O'Brien

No reason for 2 pipe systems to exist. The vacuum may be below the level that causes gassing but with 20GPH through the filter, how long until it loads up enough to cause problems? In addition, air that does pass through the pump and it does, plays havoc with combustion. Clean enough boilers that use 2 pipe and those using single or a tigerloop and get back to me.

Robert O'Brien

Hatterasguy said:

Robert O'Brien said:

In addition, air that does pass through the pump and it does, plays havoc with combustion. Clean enough boilers that use 2 pipe and those using single or a tigerloop and get back to me.

If air would go through the pump, even a minute amount of it, we would never have the stated problem on one pipe and a Tiger Loop would never be necessary.

The cleanliness, or lack thereof, of your boiler has nothing to do with one pipe or two pipe.

You're incorrect!

Robert O'Brien

Hatterasguy said:

Robert O'Brien said:

but with 20GPH through the filter, how long until it loads up enough to cause problems? .

In theory, you would conclude that it loads up 50X faster than the one pipe.

But, practice shows a different result.

You can only clean oil once. If you flow 20 GPH, you clean all the oil in less than one day. The flow rate is so high that no additional sludge accumulates during that one day. So, after that one day elapses, and the filter has done 99% of the work and it basically coasts until it sees another oil delivery.

The one pipe has to work for the entire time, albeit at a slower rate, to achieve the same result.

So, the conclusion that it "loads up" more than a one pipe is factually incorrect. It will load faster than a one pipe but never more than a one pipe.

Faster is more isn't it, when discussing an annual service interval?

Bob Bona_4

I can't imagine any joints (copper) inside of a tank. The leak paths are typically from the duplex on. The Loop wasn't designed to circumvent poor joint makeup. If that were the case, you'd have drain back every off cycle and foam in the Loop chamber every start cycle.

HUGE difference in filter load up between 2 pipe vs one pipe.

Thoeretically the boiler cleanliness should have no bearing on piping but it does real world as the system ages. 

Robert O'Brien

You are thinking of sludge as being in a fixed state and finite quantity.There are many different types of sludge, many are biological and hence reproduce.

EBEBRATT-Ed

Hattersguy said"The two pipe also has the distinct advantage of PREVENTING some sludge accumulation at the bottom of the tank due to the high flow rate.

You fellows are biased against the two pipe for all the wrong reasons. "

I couldn't agree more. The old rule of thumb to me still applies, if you have lift use two pipe. If you don't have lift use 1 or pipe

Robert O'Brien

Hatterasguy said:

Robert O'Brien said:

You are thinking of sludge as being in a fixed state and finite quantity.There are many different types of sludge, many are biological and hence reproduce.

And..........???

Would I prefer to send it to the filter as soon as it develops or would i prefer to let it sit and accumulate on the bottom of the tank and pray that it never reaches the pickup tube?

You're just being dishonest to the HO and kicking the can down the road. Someday he'll have to replace (or power flush) his tank due to your use of a one pipe system. It's inevitable.............just a matter of time.

Fix 30 or 40 thousand oil burners and get back to me, you know nothing of what you speak.

Robert O'Brien

Hatterasguy said:

Robert O'Brien said:

Hatterasguy said:

Robert O'Brien said:

You are thinking of sludge as being in a fixed state and finite quantity.There are many different types of sludge, many are biological and hence reproduce.

And..........???

Would I prefer to send it to the filter as soon as it develops or would i prefer to let it sit and accumulate on the bottom of the tank and pray that it never reaches the pickup tube?

You're just being dishonest to the HO and kicking the can down the road. Someday he'll have to replace (or power flush) his tank due to your use of a one pipe system. It's inevitable.............just a matter of time.

Fix 30 or 40 thousand oil burners and get back to me, you know nothing of what you speak.

Doing the wrong thing 30 or 40 thousand times doesn't make you any better at it.

You still don't have a technical reason for using one pipe. I use both and I know the advantages and disadvantages of both. Keeping the tank clean is most definitely not the purvey of a one tank system.

Just as you repeating the same misinformation ad nauseum doesn't make it right!

spoon22

I agree with Robert 100 percent 2 pipe is not the way to go it does clog filters faster in fact you need a bigger filter with 2 pipe because you have tripled the gph trough it. Add to that the added expense time and risk of leak not to mention oil siphon backwards at time of tune up there is no need for 2 pipe especially when there are other options for lift like a tigerloop. BTW you will never clean the tank with the filter proper additives and treatments will the filter is supposed to protect nozzle and fuel pump not clean the tank

Robert O'Brien

Some sales pitch in there but the info about air in pumps and nozzle lines is spot on.

http://www.westwoodproducts.com/images/tigerloop_is_reliability_us.pdf

Bob Bona_4

Perfect, Robert.