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Oil burner oil line switch (C) Daniel Friedman Guide to Heating Oil Burner Fire Safety Valves

  • OIL LINE SAFETY VALVES, OSVs - CONTENTS: What is an Inline fusible-link oil line fire-safety valve (OSV),and how are they used on oil fired heating equipment: boilers, furnaces, and water heaters? Fire-o-Matic or Fireomatic or Firematic® fusible link oil line shutoff valves.
  • POST a QUESTION or READ FAQs about heating oil control valves and fusible link safety valves
  • REFERENCES
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    Guide to OSVs - Oil Line Safety Valves: this article describes check valves and fusible link oil safety valves used on oil piping at heating appliances as both a fire safety device and to assist in oil burner servicing. We explain the purpose of OSVs, which way to turn the OSV or oil line safety valve to open or close it, and we describe common oil line valve installation or use mistakes.

    How & Where do We Install a Fusible-Link Firomatic™ Type Oil Safety Valve? This article series explains the installation & use of OSBs, or Fusible Link Oil Safety Valves. We describe and explain the differences in function and use among fusible link fire safety valves (OSVs) like the Firomatic®, vacuum operated OSVs like the Webster OSV and Suntec PRVs, oil line check valves, Tiger Loop and other oil system air removing devices, and oil delay valves or quick-stop valves that are also referred to as oil safety valves.

    We explain where each valve is installed and what it does. We include oil safety valve and check valve troubleshooting advice, and we describe defects in heating oil piping & control valves.



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    What is an OSV & How & Where do We Install a Fusible-Link Firomatic™ Type Oil Safety Valve?

    What are Fusible-Link Oil Safety Valves (OSVs) - definition

    Oil line safty valve in the OPEN (oil flows) Position (C) 2013 Daniel FriedmanThe OSV or oil safety valve controls flow of fuel oil to the oil burner of oil-fired heating boilers, furnaces, and water heaters. This inline oil valve is intended to close automatically and thus stop the flow of oil in the oil line in the event of a fire.

    [Click to enlarge any image]

    Some suppliers use other names for this valve including the "Firomatic" valve (R.W. Beckett) or the "Oil Safety Valve OSVA-38" (Capital City Tool, Inc.).

    Article Contents:

    [Click to enlarge any image]

    Fusible Fire Safety Valves are designed to reduce fire damage by shutting off the flow of oil from the oil tank in the event of a fire. These valves conform to UL/ULC 842 and are listed in the US and Canada. They are required by code in residential oil heating installations in conformance with NFPA 31. - R.W. Beckett [4a]

    [Click to enlarge any image]

    When the oil safety valve is open to permit heating oil to flow its movable stem and thus its internal stop valve are under spring tension.

    Because the valve includes a fusible link (a lead or other soft metal core), 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.

    Closing the oil valve or OSV means that we stop feeding oil to the oil burner in the event of a fire in the area.

    Where are Oil Line Safety Valves (OSVs) usually Installed?

    Oil burner oil line switch (C) Daniel FriedmanUsually the OSV is installed close to the oil burner both for safety reasons (close to heating equipment means close to a more likely fire source) and also for service convenience (minimizes oil spillage and maximizes convenience for the heating service tech working on the burner or oil filter).

    In our photo you can see from left to right the OSV, an oil filter, and the fuel unit (oil pump) and air intake for the oil burner.

    That vertical pipe below the fuel unit is the return line - so we know this is a two-pipe or two line heating oil set-up.

    Sometimes additional stop valves or OSVs may be installed at other locations (such as at the outlet of an above ground oil storage tank), but the critical location is at the oil burner since that's a more likely location at which a fire may occur.

    Watch out: the Firematic™ fusible-link automatic oil line shutoff valve (photo at left) should only be present on the oil supply line. We explain below
    at FIRE SAFETY for OSVs on 2-LINE OIL PIPING SYSTEMS that installing an OSV on the return line of a two pipe oil system can lead to disaster. Instead, where it is necessary to prevent leakage from the return oil line during oil burner servicing we can install a simple one-way check valve on the oil return line (if the oil burner's fuel unit manufacturer permits.)

    Our photo at below left shows an example of a Firematic™ safety valve right at the oil burner. Synonyms people use for this valve include OSV, fire safety valve, oil line valve, Fire-o-Matic valve, Fusible link valve, oil line shutoff valve, oil safety valve, and Fireomatic valve.

    Location of Fire Safety Controls at the Oil Filter

    The best place for the fusible link oil valve (Fire-o-Matic Safety Valve™ for example) is on the oil supply line just before the inlet to the oil filter canister (red arrow, below left), not between the canister and the oil burner as shown at below right (orange arrow). This allows the service tech to shut off oil just before the filter canister in order to open the canister and change the oil filter cartridge.

    Heating oil filter at the oil burner (C) Daniel Friedman Oil burner oil line switch (C) Daniel Friedman

    With the shutoff valve between the filter canister and the oil burner (above right), changing the oil filter in the canister will require the service tech to go to the more distant oil tank to find and close a valve in that location (if one is even present).

    11 May 2015 NHFireBear said:

    Regarding "the best location of an oil filter", NFPA 31 (2011): 7.5.8, for indoor tanks up to 330 gallons, requires that a thermally activated shutoff valve be placed inline as close as practical to the outlet from a tank and that a proper filter or screen be installed downstream and WITHIN SIX INCHES of the required thermally actuated valve. If it's required in the code, it doesn't have to "the best" - it just has to comply with the code.

    Discussion:

    Note that many oil heat technicians sensibly want to install a fusible-link oil supply line valve at the oil burner, not only because this makes servicing the oil burner easier but because it also recognizes that the most-likely location of a fire is at the oil burner rather than possibly at a more distant oil storage tank.

    The photograph at above left shows the right location for this safety device: at the input end of the oil filter. This permits the service technician to conveniently turn off the oil supply inorder to change the oil filter cartridge.

    Dual oil line hookup at oil burner (C) D FriedmanThe photograph at above right shows an improper fusible link oil line safety valve (OSV) - on the outlet side of the oil filter. This location means that the service tech has to find the more remote oil line shut off at the oil tank outlet - the location discussed in NHFireBear's comments above.

    At left is an OSV installedon the supply line of a 2-pipe oil tank piping system at the tank top outlet.

    The writers of NFPA 31 (2011) 7.5.8 as specified above were focused on safety including wanting to avoid oil spills from the tank, but they might also have recognizede that putting an oil filter at the oil tank protects the oil line (between tank and oil burner) from sludge-clogging.

    Some heating service techs agree with NFP31.

    (Jan 23, 2014) oilman said: Your info is wrong. the filter belongs on the tank so it also protects the oil line. If you must install at the burner, it must be piped at least 12" from the pump. Hence why they make 12" flexible oil lines.

    Reply: We agree that there is an advantage to protecting the oil line. However some HVAC instructors teach that if the filter is not installed by the burner it is too often forgotten at service time. Also putting the filter at the burner means there is a convenient shutoff valve location and air bleeder location outside the fuel unit.

    When the oil tank is a bit more remote - across the garage and buried by the homeowner's stored surfboards and hiking boots and boxes of tax receipts, the service tech enjoys being able to find the oil burner. Having inspected several thousand heating systems, my [DF] experience is that most of the time the OSV and filter are installed where they are convenient for service - which is usually close to the burner, notwithstanding the very good reasons for locating a filter at the inlet end of the oil line.

    Our OPINION [DF] is that if the technician installs an OSV at the oil burner (and ahead of a filter if one is installed there), s/he should install a second OSV on the same oil supply line at the outlet from the oil tank, particularly if the oil tank outlet piping exits at the tank bottom, and ahead of the oil filter (if that's where it's installed).

    Watch out: do not install an additional OSV on the return line of a 2-line oil piping system. Use a check valve instead.

    See FIRE SAFETY for OSVs on 2-LINE OIL PIPING SYSTEMS

    The discussion above appeared originally at OIL FILTERS on HEATING EQUIPMENT.

    Oil Line Safety Valve Manufacturers List - where to buy an OSV

    Fusible link oil line valve (C) Daniel FriedmanThe standard oil safety valve used at the oil burner and often found also at the oil tank is the Firomatic™ fusible link safety valve. The Firomatic® 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 the fusible link, a lead core, melts at 165°F 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.

    This list provides some of the companies produce fusible-link inline oil safety valves (OSVs). The footnote links point to the companies' contact information in our REFERENCES section, but generally you would purchase an OSV from your local heating equipment supplier or plumbing supplier.

    1. Asco Products (Emerson Industrial) [2]
    2. R.W. Beckett (U.S. & Canada) Firomatic Fire Safety Valves [4a] . Beckett Corporation produces /distributes a wide range of oil burners & oil burner accessories * equipment including the oil safety valve (OSV) referred to as Firomatic® fusible fire safety valves, oil line check valves, and fusible link thermal switches

      See FIREMATIC FUSIBLE ELECTRICAL SWITCH - Website: www.beckttcorp.com

      Beckett's Firomatic® OSVs are provided in both 3/8" and 1/2' sizes and in flare and threaded designs. OSVs are provided designed for installation at the oil burner and in a different model at the oil storage tank.
      • Beckett Corporation describes the Firomatic® fire safety valve as follows:

        Fusible fire safety valves are designed to reduce fire damage by shutting off the flow of oil from the oil tank in the event of a fire. These valves conform to UL/ULC 842 and are listed in the U.S. and Canada. They are required by code in residential oil heating installations in conformance with NFPA 31.

        All
        [Firomatic® fire safety] valves are embossed with the direction of oil flow and include unique part number identification ring on each valve. The seal stem uses a double seal washer/o-ring system with high grade Viton® equivalent materials suitable for No. 2 fuel oil, kerosene, and jp to 205 biodiesel blend.
    3. ISP Automation (Firematic) [1]
    4. Suntec Industries: Suntec PRV. [8][8a][9]
    5. Webster Fuel Pumps & Valves, a vacuum-activated OSV [3][7][7a].

    The current fusible link valve product properly named Firomatic is so widely also called "Firematic" and "Fireomatic" that we include those terms to assist readers in finding this information. Who manufactures the Firomatic fusible link valve? R.W. Beckett. Who manufactures vacuum-operated OSVs? Webster & Suntec (the PRV). We explain the differences among these products in this article series.

    See OIL TANK PIPING & PIPING DEFECTS for a table of normal running vacuum levels in heating oil piping installations.

    How to Tell if the Firomatic 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 position - 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 likely you'll know this also because there will have been a fire or other horrible event that melted the OSV fusible link.

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

    Oil Line Safety Valve Hazards, Mistakes, Problems

    Other Oil Safety Valve SNAFUS & Warnings

    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.

    See OIL TANK PIPING & PIPING DEFECTS for a table of normal running vacuum levels in heating oil piping installations.

    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.

    Oil burner oil line switch (C) Daniel Friedman Oil tank drain valve leak (C) Daniel Friedman

    Fire Safety for Two-Line Oil Piping Systems

    Improper use of two oil fusible link valves (C) D FriedmanWatch 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.

    The concern is that should a fire occur in the building, and should an OSV on the oil return line close before the OSV on the supply line, the fuel unit may over-pressurize the oil lines, causing a burst oil line that then sprays high-pressure oil into the fire, increasing its size and spread-rate.

    Use an oil line check valve instead. Or if the heating equipment manufacturer recommends against using a check valve in the oil piping system (Suntec prohibits, Webster recommends) then leave it out.

    The automatic oil line shutoff valve should only be present on the oil supply line.

    Further explanation of the use or prohibition of check valves in oil piping systems is
    at OIL LINE CHECK VALVES.

    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 supply 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 fire protection is right at the ol burner as well. A valve in that location also makes servicing the heating equipment easier, faster, and cleaner.

    Vacuum-Activated Oil Safety Valves, OSVs & PRVs (Webster & Suntec)

    Webster vacuum operated oil safety valve installation - Webster A vacuum-operated Webster OSV™ provides both oil line pressure protection & oil line leak protection but is not a fire protection device.

    Details about vacuum-operated OSVs and the Suntec PRV that combines the vacuum-operated valve with an oil filter are
    at OIL LINE VACUUM-ACTIVATED OSVs & PRVs.

    Here is a brief summary:

    Unlike a fusible link OSV that shuts in response to high temperature to provide fire protection at the oil burner, a vacuum operated OSV opens only in response to a "sustained vacuum" created at its outlet end when the oil burner's fuel unit pump is drawing oil from the supply.

    Vacuum-operated safety valves offer protection against oil line leaks and against overpressure conditions on the supply side of the fuel unit. They are not a fire-safety valve.

    Protection against over-pressure from the supply piping prevents leaks at the fuel pump inlet or seals that might occur when the fuel pump is not operating but the supply piping is under pressure from the oil source.

    Oil Piping Check Valves - Non Return Valves

    OSV & check valve location on oil piping - Webster Technician's Manual p. 122

    Details about check valves used (or not to be used) on heating oil piping systems are
    at OIL LINE CHECK VALVES. Excerpts are here.

    If two oil lines are used to supply an oil burner, (a supply and a return) install an oil safety valve or OSV or 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.

    If a protection against oil back-flow at the return line is a concern, and if the manufacturer recommends it, 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 in one direction only: back to the oil tank.

    [Click to enlarge any image]

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

    TigerLoop oil line de-aerator installation (C) InspectApediaWatch 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.

    Typically the oil line de aerator device such as the Tigerloop is installed at the same location as the oil filter - just before oil enters the fuel unit (oil pump), as shown in our photograph at left, provided courtesy of reader E.I..

    Our photo, left, shows a Tigerloop™ installed at a property discussed in the Q&A link given just above.

    Gas Line Safety Valves

    Fire safety valves for gas fuel lines that can shut off fuel supply in the event of a fire are also available - see our separate discussion
    at GAS SHUTOFF VALVES or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

    ...


    Continue reading at OIL LINE SAFETY VALVE TURN DIRECTION to OPEN or SHUT or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

    Or see OIL LINE CHECK VALVES

    Or see OIL LINE VACUUM-ACTIVATED OSVs & PRVs

    Or see GAS LINE FIRE SAFETY VALVES

    Suggested citation for this web page

    OIL LINE SAFETY VALVES, OSVs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

    INDEX to RELATED ARTICLES: ARTICLE INDEX to HEATING OIL, OIL BURNERS, OIL FIRED HEATERS, OIL TANKS

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