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This document describes oil safety valves used on oil piping at heating appliances as both a fire safety device and to assist in oil burner servicing. We describe defects in heating oil safety valves and how they should be installed and used. .

All of these oil storage tank and piping installation defects can easily be found by visual inspection. Beyond the costly problem of leaky oil piping, this document lists other important safety or oil-fired equipment operational defects in home and light commercial heating oil storage and piping systems. Our complete list of heating equipment controls can be found in the following articles: BOILER CONTROLS & SWITCHES and FURNACE CONTROLS & SWITCHES. Also see FIRE SAFETY CONTROLS and see DRAFT REGULATORS, DAMPERS, BOOSTERS.

© Copyright 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website.

How & Where do We Install a Fusible-Link Firematic™ Type Oil Safety Valve?

Guide to Fusible-Link Oil Safety Valves (OSVs)

The Firematic fusible-link automatic oil line shutoff valve (photo at left) should only be present on the oil supply line. This is a manual or automatic valve that will stop the flow of oil in the oil line.

This valve controls flow of fuel oil to the oil burner of heating boilers, furnaces, and water heaters.

Inline Fusible link Oil Valve: Oil line safety valves have a lead or other soft metal core that melts and closes the valve so that the system won't keep feeding oil to the heating equipment if the area is on fire. See our photo at below left for an example of a Firematic™ safety valve right at the oil burner. Synonyms: Fire-o-Matic valve, Fusible link valve, oil line shutoff valve, oil safety valve, and Fireamatic valve.

The standard oil safety valve used at the oil burner and often found also at the oil tank is the Firematic™ fusible link safety valve. The Firematic™ oil line valve can be installed in ANY position - (vertical, horizontal, upside down) at least that's what we were taught and what we have seen - the valve is spring loaded. In a fire a lead core melts at 165 degF and a spring in the valve assembly snaps the valve shut to assure that the heating system does not feed oil to a building fire. It has to work in any orientation.

At least three companies produce fusible-link inline oil safety valves (OSVs): ISP Automation (Firematic) [1], Asco Products (Emerson Industrial) [2], and a vacuum-activated OSV from Webster Fuel Pumps & Valves [3].

Watch out: A simple oil line shutoff valve may not be a fusible-link safety valve. The simple shutoff valve might be any plumbing valve that can manually stop oil flow in the line, but it is not a safety device.

Make sure you've installed a fusible-link safety valve at each location where it's most needed - at each oil burner. Even when one of these valves is installed at the oil tank the proper place for this protection is on the fuel oil supply line right at the burner as well. Why?

In the event of a fire, if the return oil line valve closes before the supply line oil valve your oil burner pump may burst the oil line or it may cause a fuel pump gasket or seal to fail, leading to uncontrolled oil flow and perhaps worse, spray heating oil everywhere, possibly feeding the building fire. Thanks to Dave Ferris for this fire safety tip and thanks to reader Rick Johnston for adding clarification. (Note that not oil burners use both an oil supply and oil return line between the oil tank and oil burner.)

Suntec points out in their installation literature for fuel units (oil pumps for oil burners) that pressures over 10 psi on an oil inlet line (normally running at a vacuum) may damage the shaft seal on the pump - i.e., leak heating oil.

SAFETY warning: If the oil line fire safety valves are missing or are not at the right location, we recommend immediate installation of a Fire-o-matic™ type oil line safety valve on the oil line at the burner.

• Recommended (red arrow, photo above left): an automatic oil line shutoff valve on the oil supply line right at each and every individual oil burner: (a type that will shut off oil supply to the heating equipment in the event of a fire, such as a Fire-o-Matic™ valve) is shown in our photo at left.
  
  By every oil burner, we mean for example that if your heating system and also your hot water heater each has its own oil burner then each burner should have an oil safety valve. (As in our photo above left).
• Oil-Tank-Only Valves are Not Recommended: A common but poor practice is to install an oil valve just at the oil tank or perhaps installing a single oil safety valve at the oil burner for the heating boiler but omitting the oil safety valve for the oil fired water heater in the same building.
• A second oil line shutoff valve on the oil supply line at the oil tank (photo above right) is ok as long as you 've also provided the first oil safety valve at the oil burner(s). Some service techs install a second oil safety valve at the oil tank or at another remote location away from the oil burner, such as at the building wall where an outdoor oil tank line enters the building, or right at the oil tank (photo at above right - this oil tank valve is leaking).
  
  This second valve is helpful if it becomes necessary to replace the oil line between oil tank and oil burner. Although our photo above shows a fusible link oil valve at the oil tank, the oil line shutoff valve at the oil tank or at a location remote from the oil burner or other more likely fire sources can be a normal plumbing stop valve.

Guide to Vacuum-Activated Oil Safety Valves, OSVs

How are vacuum type OSVs different from fusible link OSVs?

Most residential heating equipment is supplied by oil piping that moves to from oil tank to oil burner by gravity (above ground oil storage tanks) and that is under negative pressure (a vacuum) when the oil burner is running: the oil burner fuel unit is pulling oil from the tank to the burner. Typically a spring-loaded fusible-link oil safety valve such as the Fireomatic type is used on those systems.

Vacuum-activated Webster OSV valves provide protection for pressurized oil line piping systems that may be found on central heating oil supply systems for multiple mobile homes, on commercial heating systems and at other installations in which a stand-alone heating oil supply pump is delivering oil to the equipment. Webster provides instructions for OSV use on both conventional gravity-fed oil fired heating equipment and pump-fed oil fired heating equipment.

Vacuum Operated Oil Safety Valves Protect Against Oil Spills

Webster's vacuum-activated OSVs provide protection against oil spills by preventing oil siphoning out of the oil tank should there be a break or leak in the oil piping between the oil tank and the oil burner(s). These valves are used with oil supply pump or booster pump systems and they also protect against excessive oil pressure at the oil burner inlet. Quoting Webster [4],

The OSV® valve will not open during fuel unit operation if there is any air leak in the the system between OSV® and burner that prevents development of the operational vacuum required.

Where to Install Vacuum Operated Oil Safety Valves OSVs

For vacuum-operated OSVs, unlike fusible link OSVs, an OSV device is installed not at the oil burner (since this is not a heat-activated fusible link device) but rather close to the oil tank, and an individual OSV and oil feed line is provided from the tank to each heating appliance. [Webster's sketch, above-left.] In the illustration shown above left (courtesy Webster Fuel Pumps & Valves [3].) the OSVs are at the oil tank and additional service shut-off valves are at the individual oil burners.

Watch out: Webster's instructions for OSVs include this warning:

Do not mount the oil safety valve more than three feet above the lowest point in the fuel pump inlet [in most residential cases this means the oil burner fuel unit], nor more than three feet above the lowest point in the fuel line connecting the OSV to the burner fuel pump. In-line mounting with the burner fuel pump inlet is recommended.

Failure to observe the above caution may result in siphoning action in the event of failure of the fuel line between the burner fuel pump and the OSV. [3]

Fire Safety for Two-Line Oil Piping Systems

Watch out: If two oil lines are used to supply an oil burner, Do NOT install an automatic oil line shutoff on the return oil line between the oil burner and the oil tank.

Use a check valve instead. The automatic oil line shutoff valve should only be present on the oil supply line. Further explanation is below.

Our photo (left, red arrow) illustrates this hazard: you will see fusible link safety valves on both the oil feeder line (blue arrow, left side of photo before the oil filter canister) and the oil return line (red arrow, right side of the photograph).

SAFETY WARNING: If oil line valves are missing or are not at the right location there is risk of system malfunction, oil leaks, and fire damage.

We recommend installation of a Firematic™ fusible link (Fire-o-matic)™ type oil line safety valve on the oil line at the burner. This valve controls flow of fuel oil to the burner, and has a lead core which melts and shuts the valve, stopping the flow of oil in event of a fire in the building.

Even when a fusible link oil line valve is installed at the oil tank, the proper place for this protection is right at the burner as well. A valve in that location also makes servicing the heating equipment easier, faster, and cleaner.

Where do we Put the Check Valve on a Heating Oil Line?

If two oil lines are used to supply an oil burner, install a fusible link oil line shutoff valve only on the oil supply line at the oil pump on the oil burner. Do NOT install an automatic oil line shutoff on the return oil line between the oil burner and the oil tank.

Use a check valve instead. Check valves like this one permit oil to flow just in one direction. They do not close down in event of a fire. Installed on the oil return line a check valve permits oil to flow from the oil pump back to the oil tank. This makes service easier since we won't spill oil backwards out of the return line when working on the oil burner.

Check valves suitable for placement on the oil return line are available from various oil heat equipment producers including Webster.

The valve shown at left should not be used as a check valve in the application we just discussed. This is a Webster OSV & requires a vacuum to open.

If installed in the return line the valve would be pressurized, not open, cause the shaft seal to rupture or blow out & result in a major oil leak. Thanks to reader Rick Johnston for adding clarification.

Where do I Install a Tigerloop™ or similar oil line de-aerator/prime-protection device?

Watch out: Tigerloop™ warns that you should never install an oil line shutoff device between the de-aerator device and the oil pump.

Or as reader T.R. clarifies: ... I've been reading about TigerLoop oil fuel line de-aerators. When they are used, the manufacturer recommends that the fusible valve near the burner be attached at the inlet of their de-aeration device.

Details about this device are found at Tigerloop and other Oil Line Devices to Maintain Prime and Simplify Oil Piping

Frequently-Asked Questions (FAQs) about using the Oil Safety Valve on Heating Equipment

Question: What is the position of the valve stem when a Fire-o-Matic oil safety valve is OFF (closed) nd ON (open)?

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: Fusible-link oil line valves such as the Fire-o-Matic valve work opposite from usual plumbing valves

These oil line control and safety valves work backwards from what you'd expect and backwards from ordinary plumbing stop valves. The turning directions to open or close an oil line safety valve are opposite to usual water plumbing system valves.

• Turn the oil line valve clockwise (left to right) to open heating oil fuel flow. [This is opposite from usual plumbing shutoff valves]
• Turn the Firematic type valve counter-clockwise (right to left) to close the valve and stop oil 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

Oil Line Valve Open Position:

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.

As you turn the handle on the oil piping safety valve 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.

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 Closed Position:

When the oil safety valve handle is screwed all the counter-clockwise (right to left) the valve handle will become loose and the valve internal components will be in the closed position - heating oil fuel will not flow.

As you turn the oil valve knob counter-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.

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.

Frequently-Asked Questions (FAQs) about oil heating control valves & fusible link oil safety valves (OSVs)

Question: Freeing up a stick 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.

Questions & Answers regarding this article

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

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BOILER CONTROLS & SWITCHES
DRAFT REGULATORS, DAMPERS, BOOSTERS
FURNACE CONTROLS & SWITCHES
OIL TANK PIPING DEFECTS
  CAULK PIPE ENTRANCES
  FIRE SAFETY CONTROLS
  HEAT TAPE HAZARD ON OIL TANK
  OIL FILL & VENT
  OIL FILL PIPE EXPOSED
  OIL FILL / VENT PIPE CAP LOST
  OIL FILL & VENT PIPES UNDERSIZED
  OIL FILTERS on HEATING EQUIPMENT
  OIL FILTER MISSING
  OIL LINE CLOGGING FIX
  OIL LINE EXPOSED
  OIL LINE SINGLE, UP HIGH
  OIL LINE SINGLE ON BURIED TANK
  DUAL OIL TANKS - PIPING
  OIL LINE LEAKS
  OIL LINE SAFETY VALVES
  OIL TANK FILL & VENT LINES APART
  OIL TANK VENT PIPE MISSING

• [1] 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
• [2] 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
• [3] 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
• [4] Webster Service Technicians' Handbook, Webster Fuel Pumps & Valves, 219 Hahn Road Frankfort, Ky. 40601, Tel: (800) 766-1233
  
  
• Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. (416) 964-9415 1-800-268-7070 info@carsondunlop.com. Thanks to Alan Carson and Bob Dunlop, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education including the ASHI-adopted Home Inspection Training Program (home study course), publications such as the Home Reference Book, report writing materials including the Horizon report writer, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
• 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.
• "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/
• "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)
• Tigerloop: oil line de-aerator devices, Westwood Products Inc., 330 William St., PO Box 610, South River, NJ 08882-0610 - (732) 651-7700

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

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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]
• Above Ground Oil Tanks: Visual Inspection of Oil Storage Tanks for evidence of leaks, damage, improper piping - photos and text
• Above Ground Oil Tanks Checklist, an Oil Company's advice
• Above Ground Tanks UL Standards, UL Tank Listing Standards, guidance for home owners, buyers, and inspectors
• Buried Oil Tanks - Finding How to Find Buried Oil Tanks and "Nearly Hidden" and Leaky Oil Tanks - photos and text.
• Buried Fuel tank - Advice - Buried FUEL Tank - GAS or OIL advice for home buyers, inspection report language
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• Home Inspection Report Language Library: Buried Oil Tanks, Basic home buyer advice - home inspection report language suggestions
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• Leaky Heating Oil Tanks - Advice for Home Owners or Buyers: caused of leaks in oil tanks, oil tank testing alternatives, what to do about leaky tanks: D.J. Friedman, ASHI Tech. Journal, Vol.2 No.1, Winter, 1992 p. 42-43 Illus
• Leak or Failure Rates for Home Heating Oil Tanks
• Legal Issues Regarding Buried Oil Storage Tanks K.S. Rea, Attorney, summary from ASHI Chapter Seminar.
• 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
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