How to Open or Shut an Oil Safety Valve
Operating guide for fusible link oil safety valves

OIL LINE SAFETY VALVE TURN DIRECTION to OPEN or SHUT - which way do you turn the valve? How do we know if the OSV valve is open or closed?
- How to Tell if the Oil Line Safety Valve (OSV) is OPEN or SHUT
- Definitions of Types of Heating Oil Line Control Valves
OIL LINE SAFETY VALVES - separate article
FIRE SAFETY CONTROLS - separate article
OIL LINE QUICK STOP VALVES - separate article
Questions & Answers about which way to turn heating oil control valves and fusible link safety valves to open or shut the valve
References

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Oil Line Safety Valve (OSV) controls: this article explains how to open or shut the oil line safety valve used on oil fired heating equipment. We illustrate how to determine if the valve is already open or shut and we explain which way to turn the valve control knob to open or close the OSV.

Which Way do I Turn the Oil Line Fire Safety Valve (OSV or Firematic Valve) to Open or Close it?

Fusible link oil line valve (C) Daniel Friedman

Can you tell me what position the stem should be in to use the valve as a manual shutoff

— when the handle is turned to screw the stem IN the handle comes off as the stem goes into the valve body

— when the handle is turned to move the stem out of the body it reaches end of travel with ~1/4’ of stem exposed

— I want to shut the valve to change the filter feeding the furnace

- Thanks S.N.

Reply: Which Way do I Turn the Oil Line Valve to Open or Close it to Permit or Shut Off Oil Flow?

S.N. Our pair of photos just above at OPEN or SHUT POSITION of OSVs show how to tell if the OSV is open or shut. Details are below.

Fusible-link oil line valves such as the Fire-o-Matic valve work opposite from usual plumbing valves - that is, internally these oil line control and safety valves work backwards from what you'd expect and backwards from ordinary plumbing stop valves.

To Open the OSV - let oil flow: turn the oil line valve counter-clockwise (left to right - in the direction of my finger to OPEN heating oil fuel flow. [The threads on this part are cut opposite from usual plumbing shutoff valves]. As you turn the valve in this direction the threaded valve stem will protrude upwards through the rotating knob. Oil will flow when the valve is open. In my photo the valve was about half-way open.
To Close the OSV - stop oil flow: rn the Firematic type OSV clockwise (right to left) to close the valve and stop oil flow. As you turn the valve know in this direction (opposite to the direction my finger is pointing) the valve stem will disappear down into the valve body, pushed by its internal spring. You are closing the valve - oil will not flow.

Watch out: if the control valve on a heating oil line is not a fusible-link safety valve such as the Fire-o-Matic™, it will probably be an ordinary plumbing stop valve that works as all plumbing valves: clockwise closes those valves and counter-clockwise opens them. Sometimes we find a common stop valve on the oil line at the oil tank and a fusible-link safety valve just at each oil burner.

Details About Fusible Link Oil Line Valve Turning Directions to Open & Close the Valve & How the Valve Works Internally

An internal spring pressure, combined with a fusible link in the valve stem are what shut the oil line valve in event of a fire. In this design, when the valve is open to permit heating oil to flow it is also under spring tension. Because the valve includes a fusible link, in event of a fire the fusible link melts and the internal spring pushes the valve stem down, closing the valve and stopping oil flow.

Oil Line Valve Turned fully CCW (left to right) to Open Position = oil can flow

As you turn the handle on the oil piping safety valve counter-clockwise you will feel increasing spring tension as you are opening the valve (lifting the stem out of the valve body) against the spring pressure.

Because of the use of "reverse" threads on the valve stem, when you turn the OSV knob counter-clockwise the underside of the control knob, remaining in contact with the surface of the valve body, causes the valve stem to move up (against pressure of the valve's internal spring) until the threaded stem protrudes fully through the knob and you cannot turn the knob any more. In my photo the valve is about half-way open.

When the valve is fully open to permit fuel flow, the valve stem is "all the way out" of the valve body and the valve is being pushed-on by the internal spring. In this position the valve's knob has been turned clockwise, all the way down against the body of the valve.

When this oil line fusible-link valve is completely open to heating oil fuel flow, the valve stem is screwed all the way up "out" of the valve body. As you turn the valve knob clockwise you'll feel it moving against the internal valve spring pressure and you will see the valve stem moving up and out through the center of the oil valve knob.

Oil Line Valve Turned fully CW (right to left) to Closed Position = oil cannot flow

When the oil safety valve handle is screwed clockwise (right to left) so that the threaded rod has disappeared fully down into the valve body the valve handle will become loose and the valve internal components will be in the closed position - heating oil fuel will not flow.

Because of the use of "reverse threads" on the valve stem, when you turn the OSV knob clockwise , as the knob itself remains in contact with the valve body, the spring-loaded valve stem will move down into the valve body, closing off the oil flow.

As you turn the oil valve knob clockwise you will see the valve stem move back into the valve body and you will feel the spring tension on the device lessen.

For the last few counter-clockwise turns on the valve stem/screw you should feel a complete release of tension of the spring mentioned just above and if you keep turning the valve knob counter-clockwise it will unscrew and come off. Don't panic if this happens. The threaded portion of the valve stem protrudes up through the valve body and you can simply screw the knob back on.

How to Tell if the Oil Line Safety Valve (OSV) is OPEN or SHUT

In our OSV photos below, the first photo (below left) shows the oil line safety valve in the OPEN positin - oil will flow when the threaded portion of the valve shaft extends fully up through the rotatable knob pointed to by my pencil. [Click any image to see an enlarged version. Thanks to reader Bernie Daraz for pointing out the need for these two photos]

Oil line safty valve in the OPEN (oil flows) Position (C) 2013 Daniel Friedman

Oil tank drain valve leak (C) Daniel Friedman

In our heating oil line valve photo at above right the valve has been manually CLOSED - no oil will flow. The threaded valve stem has disappeared down into the valve body and has shut off the valve and oil flow.

Watch out: if (for example in case of a fire) the fusible link inside of an OSV has melted permitting the spring to close the valve, then from outside the valve may look as if it is in the open position - the threaded stem will still be poking out - but the valve has snapped and closed internally. Most likelyl you'll know this also because there will have been a fire or other horrible event that melted the OSV fusible link.

Summary of Oil Line Control Valve Open & Closed Positions

Put another way: if you turn the oil line valve until the handle begins to come off, the valve is in the CLOSED position. You will see that at this point you have removed all tension against the valve's internal spring and the spring has pushed the valve shut or closed. The valve stem has moved into the valve body.

If you turn the valve against its spring tension the valve is in its OPEN position. You will see that in this position you have turned the valve against its spring tension - the spring tension is increased - and the valve is open. The valve stem has moved out of the valve body.

We discuss using this valve for service to shut off the oil supply in our article on heating fuel oil filters found at OIL FILTERS on HEATING EQUIPMENT where during heating equipment oil filter servicing the valve is used to close and later open the oil line feeding the oil burner

Details about the different types of valves and controls used on heating piping and at oil burners are found at

Frequently Asked Questions (FAQs about Fusible Link Oil Safety Valves (OSVs) on Heating Equipment

Question: Freeing up a stuck oil line control valve?

I think I have a valve that doesn't seem to turn off when fully turned counter clockwise. Any idea why? - P.C.

Reply:

If you have a fusible link valve that doesn't seem to turn off you might try tapping the exposed end of the valve stem. I have found a stuck, or slow to close OSV on a few rare occasions. A gentle tap, not hard enough to damage threads, loosens it after which I open and close the valve a few times to convince myself it now moves freely. A burr on the brass interior or more likely internal sludge or debris could be the culprit.

Because at the oil burner the OSV is likely to be used at least once a year during service, that's a good opportunity to discover if the valve is not closing fully.

Question: What is the difference among all these different kinds of valves used on oil piping and at the oil burner or oil tank

What is the difference among all these different kinds of valves used on oil piping and at the oil burner or oil tank: check valve, fusible link valve, fire-o-matic type valve, vacuum operated valves, quickstop valves, solenoid valves, and oil delay valves. It's really confusing.

Reply:

We agree that there are enough valves and enough similarity in their names that the controls used at oil tanks, on oil piping, and at the oil burner to manage the flow of oil can be confusing. Worse, valves that do different things and have different purposes may all be called "oil safety valves" in marketing and technical literature.

Don't confuse the built-in check valve in the fuel unit with external check valves, fusible link oil safety valves, solenoid operated quick-stop oil valves, and their sisters, solenoid operated oil delay valves.

See DEFINITIONS: OIL PIPING CONTROLS for details

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Questions & answers or comments about heating oil control valves and fusible link safety valves

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Technical Reviewers & References

Related Topics, found near the top of this page suggest articles closely related to this one.

[1] Audels Oil Burner Guide, Installing, Servicing, Repairing, Frank D. Graham, Theo. Audel & Co., New York 1946, 1947, 1955 (out of print, copies occasionally available from antique book dealers and on EBay)
[2] Beckett Model SR Oil Burner Instruction Manual, R.W. Beckett Corporation, PO Box 1289, Elyria OH 44036 and R.W. Beckett Canada, Ltd., 430 Laird St., Guelph, Ontario, Canada N1G 3x7
[3] Thanks to Bottini Fuel service tecnician Bob for discussing the buzzing aquastat relay problem, 4/18/2012. Bottini Fuel is a residential and commercial heating oil distributor and oil heat service company in Wappingers Falls, NY and with offices in other New York locations. Bottini Fuel, 2785 W Main St, Wappingers Falls NY, 12590-1576 (845) 297-5580 more contact information for Bottini Fuel
[4] Beckett Model SF Oil Burner Instruction Manual, op.cit.
[5] Sunstrand Corporation - Sunstrand Fuel Units, 4949 Harrison Avenue P.O. Box 7003 Rockford, Illinois 61125-7003 U.S.A. Telephone: (815) 226-6000 Fax: (815) 226-5399 http://www.sundstrand.com
[6] Sunstrand Transmission Service Manual, May 1974, web search 08/19/2011, original source: http://www.cushmantrackster.com/pay-pdfs/sundstrand.pdf - Sunstrand Series 15 hydrostatic transmissions
[7] Webster Fuel Pumps & Valves, Capitol City Tool, Inc., http://www.websterfuelpumps.com/
[8] Suntec Model A-7400 Fuel Unit Solenoid Dumping Pump,
Suntec Industries Inc., 60 Aberdeen Drive - PO Box 5000 Glasgow, KY 42142-5000 - USA Tel : 270 651 7116 - Fax : 270 651 9276 e-Mail : info@suntecpumps.com and
Suntec Industries France, 1 Rue Lavoisier - B.P. 102 F-21603 LONGVIC Cedex - FRANCE Tel : +33 (0)3 80 70 60 70 - Fax : +33 (0)3 80 70 61 11 e-Mail : information@suntec.fr, [copy on file as /heating/Oil pumps fuel units/Sunted_Solenoid_DumpingPPump.pdf] ,
Also /Suntech_Solonoid_Safety_Valves.pdf (brochure)
web search 4/19/12, original source: http://www.suntecpumps.com/Suntecus/PDFs/Form%202740%20
-%20Solenoid%20Dumping%20Pump.pdf
[9] Suntec Model PRV-38 Oil Safety Valve Installation Information, untec Industries Inc., 60 Aberdeen Drive - PO Box 5000 Glasgow, KY 42142-5000 - USA Tel : 270 651 7116 - Fax : 270 651 9276 e-Mail : info@suntecpumps.com and
Suntec Industries France, 1 Rue Lavoisier - B.P. 102 F-21603 LONGVIC Cedex - FRANCE Tel : +33 (0)3 80 70 60 70 - Fax : +33 (0)3 80 70 61 11 e-Mail : information@suntec.fr, [copy on file as /heating/Oil pumps fuel units/Form 2155 - PRV-38 Installation.pdf]. You can download this file from Suntec's website. ,
[10] Firomatic Globe Type Oil Line Valves & Lever Type Fusible Link Control Valves: ISP Automation, Inc., 1035 Old Georges Road, North Brunswick, NJ 08902, Phone: 866-383-3481, FAX 866-383-3482, Email: support@ispautomation.com
[11] Fusible link oil line control valves for commercial equipment: ASCO products by Emerson Industrial Automation, P.O.Box 160, 17 Airport Road Brantford, Ontario Canada N3T 5M8 Tel: (519) 758-2700 Fax: (519) 758-5540
[12] Fuel oil safety valves, Webster Fuel Pumps & Valves, 219 Hahn Road Frankfort, Ky. 40601, Tel: (800) 766-1233 Email: czahalka@cctoolinc.com (Curtis Zahalka Sales Mgr/Mkt /Cust Service/Tech Support/Webmaster ) web search 10/12/2011 original source http://www.websterfuelpumps.com/pdffiles/osv1.pdf
[13] Webster Service Technicians' Handbook, Webster Fuel Pumps & Valves, 219 Hahn Road Frankfort, Ky. 40601, Tel: (800) 766-1233
[14] "The Oil Safety Valve (Service)", Charles Bursey, Sr., Fuel Oil News, February 2006 (Still trying to get the full article - October 2008 - DF) Charles W. Bursey Sr. can be reached at F.W. Webb Co. www.fwwebb.com/
[15] "Installation Information for Suntec A-2000, A-7000 Single Stage and B-8000 two stage fuel units"Suntec Industries, 60 Aberdeen Drive, Glasgow KY 42141, 270-651-7116 (1725 rpm black label, 3450 rpm white label)
[16] Tigerloop: oil line de-aerator devices, Westwood Products Inc., 330 William St., PO Box 610, South River, NJ 08882-0610 - (732) 651-7700
[19] Thanks to reader Bernie Daraz for suggesting the need for clear photographs illustrating the OSV or oil line safety valve in the open and closed positions. Personal correspondence 2/15/2013.
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. (416) 964-9415 1-800-268-7070 info@carsondunlop.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides:
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Dave Ferris - M&S Environmental Systems, Dutchess County, New York. Mr. Ferris was an HVAC expert. Personal communication to DJF 1987. Remove the firematic or fusible oil supply line valve on return oil-line side - in case of fire if this one closes first the pump continues to run, blows its seal, and sprays oil all over the fire. Proper installation is to have a fusible link valve only on the supply side, and to install a check valve on the return line to prevent back-siphonage from the tank.
Thanks to Rick Johnston for pointing out that the more likely cause of a fire safety valve in the return oil line is a burst seal on the fuel unit 4/6/2009
Thanks to reader T.R. for suggesting clarity on where oil safety valves should or should not be installed and for discussing the proper hook-up location for the Tigerloop and similar oil line prime protection & air removal devices. April 2011.

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Carson Dunlop, Associates, Toronto, have provided us with (and we recommend) Carson Dunlop Weldon & Associates' Technical Reference Guide to manufacturer's model and serial number information for heating and cooling equipment
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Oil Tanks - The Oil Storage Tank Information Website: Buried or Above Ground Oil Tank Inspection, Testing, Cleanup, Abandonment of Oil Tanks
Abandon a Buried Oil Tank, How To - Abandoning Commercial Underground Tanks, Russ Brauksieck, ASHI Tech. Journal, Vol.3 No.1 Spring 1993, P. 40-41 [Reprint]
Primer on Petroleum Bulk Storage Tanks & Petroleum Contamination of Property Paul H. Ciminello, ASHI Tech. Journal, Vol.3 No.1 Spring 1993, p 35-39
Petroleum Bulk Storage J. Sibblies, NY State DEC, Advice to Home Owners and Home Inspectors about Oil Storage Tanks - summary from ASHI Chapter Seminar.
...


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Which Way do I Turn the Oil Line Fire Safety Valve (OSV or Firematic Valve) to Open or Close it?

Reply: Which Way do I Turn the Oil Line Valve to Open or Close it to Permit or Shut Off Oil Flow?

Details About Fusible Link Oil Line Valve Turning Directions to Open & Close the Valve & How the Valve Works Internally

Oil Line Valve Turned fully CCW (left to right) to Open Position = oil can flow

Oil Line Valve Turned fully CW (right to left) to Closed Position = oil cannot flow

How to Tell if the Oil Line Safety Valve (OSV) is OPEN or SHUT

Summary of Oil Line Control Valve Open & Closed Positions

Frequently Asked Questions (FAQs about Fusible Link Oil Safety Valves (OSVs) on Heating Equipment

Question: Freeing up a stuck oil line control valve?

Reply:

Question: What is the difference among all these different kinds of valves used on oil piping and at the oil burner or oil tank

Reply:

Questions or comments about this article

Technical Reviewers & References

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair