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Fire Protection System Firestat
NOTE: There must be adequate clearance above the hood to access components. 18-inches of
service clearance is recommended.
The Firestat is a device installed in the riser of the hood, at the duct connection, that measures
temperature. The standard temperature setting is 360°F. Depending on heat produced by appliance, a
higher rated temperature Firestat will be required. If a temperature higher than the setpoint is sensed, the
Firestat contacts will close and energize the electrical control board. The fire system will activate, the
system will run for a minimum of 15 minutes and then recheck the temperature. If the temperature is still
higher than the setpoint, the process restarts immediately.
The Firestat has 2 black wires and 2 white wires. These wires must be connected to the supervised loop.
Use high-temperature wiring when installing Firestat components. High-temperature wire-nuts or terminal
blocks must be used. There must be one sensor installed for every 12 feet of hood length.
Multiple sensors are wired in parallel in the supervised loop. The Firestat may be installed on the opposite
side of the quick seal for access in the duct.
Non-Solid Fuel Appliances (Rated 450°F)
Non-solid fuel appliances rated for 450°F will not require additional firestats, regardless of the configuration
and length of ductwork.
Non-Solid Fuel Appliances (Rated 600°F)
Non-solid fuel appliances rated for 600°F will require downstream detection if the duct run contains any
horizontal section over 25 feet in length. Downstream detection should be installed at the end of a
horizontal section. Duct layouts that include less than 25 feet of horizontal ductwork will not require
additional detection.
NOTE: When additional Firestats are required, install in an accessible location near an access
door, hood riser, or fan. The door will provide access to install, clean, and replace the Firestat
when needed. If a PCU is equipped with electronic detection, PCU Firestats can serve as
downstream detectors, if present. The temperature rating of the Firestat in the duct must always
match the temperature rating of the Firestat in the riser.
Summary of Contents for EWC
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