Fire Suppresion System Question

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[LarryFine]

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[LarryFine]

I wondered why the two exhaust contactor coils are wired for non-coincidental operation. Explain, please, including why only one is switched?

You could omit the relay; standard micros have a 20a capacity, and can even run a 120v motor; they only do so when testing or an actual system trip.

Imagine incoming power goes to the exhaust switch and the micro C. Micro E feeds out from exhaust switch, so they're in parallel; either turns on exhaust.

Micro N feeds light switch and MU switch, along with any appliance contactors, so a trip energizes the exhaust and removes power from everything else.

We usually have horn/strobes to energize, too; every system control head I've seen has two micros, so the second can be used for that, shunt-trips, etc.

Make sure shunt trips can withstand continuous power. Also, you show contacts atop shorting your power supply. Are there supposed to be coils?

 

[gadfly56]

I wondered why the two exhaust contactor coils are wired for non-coincidental operation. Explain, please, including why only one is switched?

You could omit the relay; standard micros have a 20a capacity, and can even run a 120v motor; they only do so when testing or an actual system trip.

Imagine incoming power goes to the exhaust switch and the micro C. Micro E feeds out from exhaust switch, so they're in parallel; either turns on exhaust.

Micro N feeds light switch and MU switch, along with any appliance contactors, so a trip energizes the exhaust and removes power from everything else.

We usually have horn/strobes to energize, too; every system control head I've seen has two micros, so the second can be used for that, shunt-trips, etc.

Make sure shunt trips can withstand continuous power. Also, you show contacts atop shorting your power supply. Are there supposed to be coils?

In addition to the 20 amp capacity, the most popular systems, Ansul, Kidde, Pyrochem, Badger, Range Guard, and Buckeye can accommodate up to 4 switches. You would only need a contactor if you are over the amp range or switching multi-phase loads. Kidde's switches will also handle up to 250 volts.

 

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[LarryFine]

The power that trips the shunt-trip breaker should be supplied from that breaker, so the coil is immediately de-energized after it trips. Is the range its only load, or does it supply a sub-panel?, Since it's already there, how was it wired to trip before? :?

Contactors for both fans, obviously. Are the lights and receptacle separate circuits? Is this a single 120v receptacle? It can possibly run through the micro or be on a contactor. If more than one circuit, they can share one multi-pole contactor. Details!

 

[AC\DC]

Rang is its only load

it’S an old KFC that has been vacant for 15 years. I don’t know how it worked. The fire marshal said it was decommissioned “forgot his exact word” the only pipe/wires going to it are from the emergency shut off.
The MUA goes straight from Main distribution panel to disconnect on roof
Original breaker looks like so it was not swapped out

lights and receptacles are desperate circuits in spectatet Panels

Another good idea for the single contact and just switch the lights after the contact.