• Volume 18, Issue 1 | 1st Quarter

    Feature Article

    Restaurant System
    Replacement Parts

    By Mark Conroy


    Every six months or after a system actuation, a system maintenance technician services the wet chemical extinguishing system that protects kitchen appliances, hoods, and the exhaust ducts. The work is conducted in accordance with the manufacturer’s service manuals. Some components and parts are routinely replaced, while others that might cause impairment or failure of the system are also replaced at that time. Knowledge of system parts/components and their purpose is essential in order to ensure the system will function as intended. Here is a description of some of those essential components and parts along with things to keep in mind while performing the semi-annual maintenance of restaurant systems.

    NFPA requires that all discharge nozzles be provided with caps or other suitable devices [17A:]. As part of the 6-month maintenance service, these components need to be examined. Missing or loose caps and damaged foil seals need to be replaced. Additionally, silicone grease should be applied to caps every 6 months. Here are the most common types of nozzle protection devices in use today.

    Rubber Blow-Off Caps

    A rubber blow-off cap keeps the orifice of a nozzle free of grease and contaminants, which can interfere with proper agent distribution. An integral part of the blow-off cap is the retaining strap, which attaches to the nozzle. The strap keeps the cap attached to the nozzle after system discharge.

    Metal Blow-Off Caps

    Metal blow-off caps are sometimes used as substitutes for rubber blow-off caps. A metal blow-off cap is attached to the nozzle with the integral stainless steel wire. The wire keeps the cap attached to the nozzle during discharge and prevents it from falling into or onto an appliance.

    Nozzle Caps and Seals

    For some system nozzles, a cap and foil seal is used to keep grease and contaminants from accumulating in the nozzle orifice. The foil seal ruptures when agent discharge occurs and must be replaced before the system is put back into service. The foil is held in place by the nozzle cap.

    Blow-off Cap Grease

    Dow Corning® Silicone Grease No. 111 (P/N SL111) is the recommended grease for both rubber and metal blow-off caps. Grease is applied at the 6-month maintenance interval.NFPA allows penetrations in hoods to be sealed by devices that are listed for such use [96: 5.1.5]. Also, any penetrations that result from the removal of conduit or piping are required to be sealed with liquid-tight sealing devices [96:].

    NFPA allows penetrations in hoods to be sealed by devices that are listed for such use [96: 5.1.5]. Also, any penetrations that result from the removal of conduit or piping are required to be sealed with liquid-tight sealing devices [96:].

    “Grease-Tite” Adaptors

    Jiffy “Grease-Tite” adaptors are UL listed mechanical fittings that form a liquid-tight seal around distribution piping or detection cable conduit. These adapters are installed wherever there is a need to penetrate a restaurant hood or duct.

    Corner Pulley “Grease-Tite” Adaptors

    These Jiffy adaptors’ intended use are with a high-temperature corner pulley. Adaptors create liquid-tight seals around 1/2 inch EMT conduit. Typically, these adaptors are needed where a corner pulley is needed to make the 90° change in direction from a detector bracket through the top of a hood.

    Seals for Holes in Hoods

    Whenever pipe or conduit is removed from a hood, the remaining hole in the hood must be plugged and form a grease-tight seal. UL listed Jiffy Patch “Grease-Tite” Seals are installed to cover un-wanted holes without welding.

    Restaurant systems are mechanical, and stainless steel cable is used for actuation of the system, including connections to fusible links and pull stations. Cable is also used to trip mechanical gas valves. To work properly, and with little friction, pulleys with ball bearing rollers are installed to provide a 90° change in direction. Here are some of the most common pulleys used in the industry.

    High-Temperature Corner Pulleys

    There are two types of high-temperature corner pulley elbows that are installed, whenever a 90° change in direction of conduit is needed within a hood. P/N CP8 has socket connections and set screws for connecting to 1/2 inch conduit. P/N CP5 has compression fittings for connecting to 1/2 inch conduit.

    Corner Pulleys with Swing-Covers

    All swing-cover corner pulleys are intended for low temperature installations (outside restaurant hoods). P/N CP6 has socket connections and set screws. P/N CP7 has 1/2 inch threaded (NPT) connections.

    Tee Pulleys

    Tee pulleys are installed where two cables from a mechanical release module each need to make a 90° change in direction. Typically the application is a cable for mechanical gas valve shutdown and cable for connection to a pull station. Tee pulleys are never installed for detection cable applications.

    Stainless Steel Cable

    FireTech™ aircraft type (7x7) stainless steel cable is used for all restaurant system applications, including connections to fusible links, pull stations, and mechanical gas valve trips. Make sure to have an adequate supply of metal crimps and S-hooks for connections to the stainless steel cable. The tools to use with stainless steel cable are P/N CC093 cable cutters and P/N ST116 crimping tool.

    Upon activation of any restaurant system, NFPA requires that the fuel and electrical power that produces heat to the appliances, requiring protection, be shut off [96: 10.4.1]. Shutoff devices require a manual reset [96: 10.4.4].


    Mechanical Gas Valves

    Upon actuation of a restaurant system, the mechanical gas valve automatically shuts off. The most common type of gas valve is the Trip-to-Close ASCO™ mechanical gas valve (P/N GVB). These valves are available to connect from 3/4 to 3 inch pipes.

    Electrical Gas Valves

    ASCO™ electrical gas valves (P/N GVC) are the industry standard and come in sizes 3/4 to 3 inch. They are normally closed without power, so the valve is held open when the solenoid is energized. Valves must be installed so the solenoid is vertical and upright.

    Manual Reset Relays

    A manual reset relay (P/N SRR) is a safety feature and is required where an electrical gas valve is employed. When an electrical gas valve closes, due to system actuation or a power outage, the valve cannot be opened until the reset relay button is pressed.



    There are many electrical devices that must either be turned off or turned on when a restaurant system actuates. These devices include, but are not limited to, building fire alarms, electrical gas valves, contactors, lights, and electrical power shutoffs. P/N MIC1 is a single-pole, double-throw and P/N MIC2 is double-pole, double throw. Other switches specific to system manufacturer are also available.

    NFPA requires the wet chemical that is used in the system to be listed for the particular system [17A: 4.6.1]. After any discharge, the piping must be flushed and blown out with dry air or nitrogen [17A: 7.4.3]. The supply of wet chemical for recharging the system needs to be stored in the original closed shipping container [17A: 7.4.4].


    Wet Chemical Recharge Agent

    Wet chemical extinguishing agent is a solution of water and potassium acetate, potassium carbonate, potassium citrate, or a combination of these chemicals. When the extinguishing agent is discharged onto a cooking appliance fire, soap-type foam is created on the surface of a cooking oil fire (excluding air), extinguishing the fire. Wet chemical recharge agent must match the system manufacturer.

    Servicing wet chemical extinguishing systems every 6 months helps ensure the system will work as designed. Your knowledge of how system parts play a role in system operation is critical. Also routinely placing parts, according to the manuals, and replacing potential problematic components and parts is essential to keep the system operational. The system owner can rest assured that your knowledge and compliance with the national standards and the manufacturers’ service manuals will ensure safety and maximizes the ability of the system to extinguish a fire, should one ever occur.

    Mark Conroy is an engineer in our Boston office and a member of the NFPA Technical Committee on Venting Systems for Cooking Appliances.

    Employee Spotlight

    Meet Chelsea Lord

    Strategic Accounts Representative

    On August 1st, 2016, Brooks welcomed a new employee—Chelsea Lord. Coming from the Hospitality Industry, she brought a lot of customer service experience with her. And that experience has paid off big time, both with her customers and with her colleagues. Always smiling, her enthusiasm for her work is down right infectious. As she simply puts it, “I exchanged Hotel Reservations for Fire Extinguishers and have never looked back.”

    A proud member of the Brooks Strategic Account Team, Chelsea works hard building relationships with her Brooks customers. She appreciates their position and goes the extra mile to assist them, because she really cares. Whether it’s a quote, order, question, concern—whatever, she manages to find the best solution to each and every customer query.

    When asked what she enjoys most about working at Brooks, she smiles and quickly says, “Learning. I learn something new every single day, which is my absolute favorite part of working at Brooks.” Spending the majority of her time on the phone, she appreciates the unique perspectives and specific knowledge her customers bring to the table.

    And it’s not lost on her how important it is what her customers do—protecting lives and property. “I care about my customers and their businesses. I come to work every day with the intention of making sure they have my undivided attention as well as every resource at my disposal to help them succeed,” she says. She means it too. So the next time you’re on the phone with her, know that she’s got your back, and that she’s smiling, even though you can’t see it.

    A “bibliophile” (bookworm) since she was knee-high to a grasshopper, you’ll find Chelsea reading or writing when she’s away from work. And when she’s not feeding her literary fancy, she’s probably curled up on her comfy couch with a bowl of pasta (I hope with sauce) and her four-legged owner, Soukie the cat, on her lap meowing orders (a very possessive feline). Of course the TV’s on, and they’re most likely watching some documentary on the British Monarchy (Soukie’s favorite). Long Live the Cat...I mean Queen!

    Disclaimer: The opinions expressed in these articles are the author’s only and provide limited information. Although the information is believed to be reliable, Brooks Equipment Company, LLC expressly disclaims any liability for errors or omissions. The user of this article(s) or the product(s) is responsible for verifying the information’s accuracy from all available sources, including the product manufacturer. The authority having jurisdiction should be contacted for code interpretations.