Programming Class A fire circuits


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Old 02-25-24, 03:57 PM
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Programming Class A fire circuits

Class A fire circuits are characterized with two sets of two-conductor wire going out to the device and back with the intention of having a continuous connection to the device if one of the wires is compromised. That being said, I do not believe that they have an EOL and the panel [an old Silent Knight 5207] goes into alarm on an open in the circuit. Is this correct?

I need to add a zone on the panel and the only free zones are 1 & 2 which are both Class A.

Thanks for any insight you can provide.
 
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Old 02-25-24, 07:55 PM
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There is no EOL used on Z1 or Z2. Strictly class A open circuit.
For example: If the wire going from the switch to #2 opens...... #5 still carries the circuit.
An open wire would create a fault..... not an alarm.


 
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Old 02-26-24, 04:33 AM
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[size=22px]Note the second line to the right of the terminals in Post #2. [/size]

[size=22px]Depending on the age of the panel, activation of a Class A zone might affect output operation.[/size]

[size=22px]For example: Class A zones were often included to signal water flow in a sprinkler system (I believe Class A is still required for waterflow in many jurisdictions). Fire alarm panels [/size][size=22px]did not allow silencing if water was still flowing.[/size]

[size=22px]If they are still made, there is a zone expander for the 5207. Otherwise, sounds like it's time for a new panel.[/size]
 
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Old 02-26-24, 03:55 PM
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The zone type selected in programming determines if the zone is silenceable, and with these old 5207 panels, individual zone inputs can be selected as silenceable or non-silenceable. You can use the class A Input for any normally open, contact closure circuit, but you have to make the wiring conform to class A specs.

You can make pseudo-class A by wiring your new circuit with 4 conductor wire, using the 2nd pair to return from the last device back to the fire panel. That will provide mechanical supervision to the circuit.
 
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Old 02-26-24, 07:25 PM
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Thanks for the input.

It is a restaurant's Ansul system in an old strip mall that is near the waterfront so I don't think the building will be around much longer -- Not sure I can still get the expander so hopefully the Class A will fill the bill. Just going to use a 4-conductor -- Not to code, but I don't think it will matter at this point.

Not sure why the fire marshal is just now requiring it since the restaurant has been there many years without coverage.
 
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Old 02-26-24, 08:31 PM
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I've had the same issue recently with tying the Ansul to the panel.
Two older restaurants where nothing has changed.


 
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Old 02-27-24, 02:23 AM
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Most likely, your state updated it's fire/life safety code. Fire marshals have been moving away from the "grandfathering" of existing installations for quite some time.

The 4 conductor solution isn't a true class A circuit, but it is still a supervised circuit, so you can treat it as a class B for all functional (and code compliance) purposes.

The SK5207 is _long_ discontinued, so, short of a lucky "new old stock" find, you are unlikely to find any parts like that expander board. Heck, SK quit making conventional fire alarm controls a couple of years ago.
 
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Old 02-27-24, 02:51 PM
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A little off topic.....
We are shaking right now.... many current panels are no longer code compliant and parts are no longer available.

We are a Bosch dealer and their current basic fire panel FPD-7024 is no longer NEW code compliant and is discontinued..... as well as the peripherals. That means in and out modules, expanders are all gone. We've been buying parts from out of the country.

We have a ton of Silent Knight 5820 panels running Hochiki devices.
I have one building with 350 Hochiki devices.... I'm to replace all of them to be code compliant.

Existing sites can replace all Hochiki SD devices with Farenhyt IDP devices to continue using the existing panel.
Honeywell will take a phased approach to the product end-of-life to allow customers time to transition installed systems to other products. Additionally, the Hochiki SD photoelectric detectors are only listed to UL268 6th edition; this timing will ensure the conversion is complete well before the UL268 7th edition 2024 effectivity date. The product line will be fully discontinued on December 31, 2023.


Geez... thanks.
 
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Old 02-27-24, 05:27 PM
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Yikes! I'd not spotted the notice that Honeywell is ditching the SD protocol devices. That explains why the modules I just got were back-ordered for weeks. I guess I have some letters to make to send to some of our service customers. We don't install SK products, generally, but a _lot_ of our service customers have existing installations...
 
 

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