Placement of OSV in Oil Fired Boiler Heating System With Above Ground Outside Tank

fiddletank

My boiler tech placed a Webster OSV in the fuel line On The Top of my OUTSIDE oil tank to prevent an oil spill from a potential break in the fuel line between the top of my tank and the wall of the crawl space beneath my house 7 feet away.

NOTE: The top of the oil tank is 6 1/2' above grade.
The TOP of the oil tank is approximately 7 1/2' above the lowest point in the fuel
line run to burner.( fuel line runs 1' underground to the crawl space wall)
The top of the tank is also 4 1/2' above the burner 55' away.

The Webster OSV installation sheet notes that the OSV should be placed on fuel line as close to the tank as possible..AND " no more than 3' above the fuel unit inlet or more than 3' above the lowest point in the fuel line connecting the OSV to the burner fuel unit"

Looks like I am out of the acceptable range for OSV placement.
Why is this range so critical?
What kind of problems might I encounter if I keep the OSV on top of the tank?

I tried to connect with the Webster tech folks but was not successful.

Will appreciate all that collective wisdom out there.

STEVEusaPA

I can’t actually picture your set up, but I’d place it the farthest from the burner and 3’ higher than the burner.
The OSV job is to prevent high inlet pressure to the fuel pump and prevent a gravity leak from the tank. Putting it at the top of the tank will probably create more problems.

fiddletank

If OSV is designed to prevent/stop oil spills between tank and burner, why wouldn't the best location of OSV be on top of my above ground tank where the fuel line enters the tank? Wouldn't this prevent any oil coming out of fuel line by siphon/gravity?

As for inlet pressure to fuel pump, i have had an underground tank for 27 years and never had a inlet pressure problem. Does having an aboveground tank where the oil out flow at tank top is 4 1/2' above the burner expose me to new inlet pressure problems?

leonz

Hello fiddletank,

here is a link if you do not have the sheet in your paperwork and the installation manual.

The section for the OSV starts on page 126. The page you need to look at is page 127.

It would be wise to have a paper clip tied to the fuel line at the Oil Safety Valve with nylon twine to allow you to manually activate the OSV by depressing the diaphragm plate if the burner is not firing.
Having a vacuum gauge installed at the burner would also help you if there is a problem with no fuel flow to the oil burner.


www.websterfuelpumps.com/trouble.htm#


www.websterfuelpumps.com/pump_docs/LL4640.pdf

STEVEusaPA

Here's pretty much all you need to do/know.

HVACNUT

leonz said:

Hello fiddletank, It would be wise to have a paper clip tied to the fuel line at the Oil Safety Valve with nylon twine to allow you to manually activate the OSV by depressing the diaphragm plate if the burner is not firing. 

Or you could get one of these.

PatN

https://www.preferred-mfg.com/products/fuel-handling/fuel-oil-components/valves/anti-syphon-
Different valves for different applications. See links below.



https://www.preferred-mfg.com/products/fuel-handling/fuel-oil-components/valves/anti-syphon-valves.html
Anti-Siphon Valves | Preferred Utilities Mfg

Installed in a vertical position at the highest point in the suction line with no part of the line between the valve and the tank below the maximum oil storage level. UL listed; Approved by the New York City Board of Standards and Appeals.
www.preferred-mfg.com

http://www.haseloh.ca/oil-safety-valve.html
Oil Safety Valve
oil line safety valve, oil tank safety valve, oil safety valve
www.haseloh.ca

https://www.websterfuelpumps.com/osv.htm

STEVEusaPA

HVACNUT said:

Or you could get one of these.

I never bought one of them.
Webster-bent piece of bare 14ga wire and a pony clamp.
Suntec-Just a pony clamp.

seized123

PatN said:

http://www.haseloh.ca/oil-safety-valve.html Oil Safety Valve oil line safety valve, oil tank safety valve, oil safety valve www.haseloh.ca 

@PatN made the above suggestions (the Preferred Utility one too, thanks again Pat) in another thread when I was asking about anti-siphon valves to go at the top of my tank. In my own quest I discovered that at least anecdotally (pros welcome to provide contrary evidence, I’m not a pro) even though an AS valve right at the source makes a lot of sense to me, it is just not done residentially, at least around here. Three successive techs looking at my system (similar to yours) had no idea what an anti-siphon valve is. But I’m actually surprised such a thing at the tank is not mandated, given the immense downsides to an oil spill.

I did not want the OSV’s mentioned (Suntec,Webster) which I’m sure are great products, but at 3’ max above burner they would leave most of the oil line uncovered (top of my tank is about 8’ above burner).

So I looked into the Preferred Utilities valves Pat mentioned and even talked to one of their engineers who seemed surprised that I was considering using theirs since they are really for commercial and he said I could certainly find one cheaper than theirs.

I looked into the Haseloh valve (could find no other similar thing which I find amazing) and it is a tiny Canadian company with almost zero internet presence (great customer service if you call them) and it’s affordable and I got one and if it holds up it is just what I was looking for. Below are links to a couple videos they made about the valve and another showing an installation (very simple). And for good measure there’s a photo of the valve I got, the silver thing is an adapter the valve goes into.

Be aware that they require you have a Tigerloop or similar and the valve wouldn’t cover the small return line between the pump and the de-aerator, but I believe no anti-siphon valve would.

If I hadn’t found the Haseloh I probably would have shelled out the bucks for the Preferred Utilities if it could work for my setup.

https://www.youtube.com/watch?v=vjzR7K8JVjo


https://www.youtube.com/watch?v=_95Q1gqQJ1A

https://www.youtube.com/watch?v=7rUrVjNjuN4