Need help understanding zone 16 and 2 wire smokes

CORT

Active Member
Hello,

I am trying to understand what happens when the jumper on Elk's M1 zone 16 is placed in the 2 wire smoke detector mode. Electrically, what does this do to the M1? Does it process the signal coming into zone 16 differently? Why does this call for and 820 ohm EOL instead of a 2200k EOL? Thanks.
 
Hello,

I am trying to understand what happens when the jumper on Elk's M1 zone 16 is placed in the 2 wire smoke detector mode. Electrically, what does this do to the M1? Does it process the signal coming into zone 16 differently? Why does this call for and 820 ohm EOL instead of a 2200k EOL? Thanks.

A 2-wire smoke gets power on the same pair of wires that are used to monitor the zone. This requires some different circuitry so you have a jumper and a different EOL resistor value.
 
Hello,

I am trying to understand what happens when the jumper on Elk's M1 zone 16 is placed in the 2 wire smoke detector mode. Electrically, what does this do to the M1? Does it process the signal coming into zone 16 differently? Why does this call for and 820 ohm EOL instead of a 2200k EOL? Thanks.


The jumper allows the power for Zone 16 to come off of the SVAUX buss. This buss will power down for 5 seconds during a smoke detector reset thus resetting the smoke detectors on Zone 16. The jumper should only be used in that position when 2 wire smoke detectors are used (otherwise it is a normal zone).

The 820 ohm EOL resistor is used to maintain the proper "trip window" for 2 wire smoke detectors that were specifically evaluated for use with the ELK M1. The trip window for a 2 wire smoke is different than a 4 wire smoke or a contact switch etc for burg. When zone 16 is used for anything other than 2 wire smoke detectors the 2200 ohm resistor should be used.
 
So basically, setting the jumper on zone 16 for 2 wire smoke detectors allows for resettable 12v power to reset the detectors without making the M1 go nuts. Zone 16 in 2 wire smoke mode is only for active devices such as smoke detectors. Right?

If I install heat only detectors, how are they configured? I suspect they should be on a separate zone from any 2 wire smoke detector; configured as 24 hr fire alarm zones; optioned as 4 wire devices (even though only 2 wires are used); and wired with a 2200 ohm EOLR. Does this sound right?

Thanks
 
I never tested the clean me feature so I am not familiar with it.
That's one of the advantages of the 2 wire detectors. They send a "clean me" signal to the M1 and flash their led's when they need to be cleaned/inspected.
 
If I install heat only detectors, how are they configured?
Heat detectors are just a NO switch you can configure them with or without an EOL. They can be set to any zone and I configure them as a 21=Heat Alarm.

Edit: NO not NC.
 
What is the "clean me condition"? Is it a certain resistance across the zone?
I think it actually checks the dirtyness of the screen and the internal workings. When you get the signal you take the smoke apart and vacuum/clean the parts according to the instructions.
 
What is the "clean me condition"? Is it a certain resistance across the zone?
I think it actually checks the dirtyness of the screen and the internal workings. When you get the signal you take the smoke apart and vacuum/clean the parts according to the instructions.


Clean me is usually when the detector self test function determines that it is out of its sensitivity range. It then notifies a compatible panel so that you can perform the maintenance recomended by the manufacturer (usually vacuuming as you stated).

I personally feel that a homeowner should not take a smoke detector apart.
 
If I install heat only detectors, how are they configured?
Heat detectors are just a NC switch you can configure them with or without an EOL. They can be set to any zone and I configure them as a 21=Heat Alarm.
What is the difference between heat alarm and fire alarm?

A heat alarm (thermal detector) senses a fixed temperature (usually 135 or 194 degrees) or a rate of rise (usually 15 degrees within a minute). It then closes a contact.

A smoke detector senses smoke by using either a ionization chamber or a photoelectric chamber.
 
If I install heat only detectors, how are they configured?
Heat detectors are just a NC switch you can configure them with or without an EOL. They can be set to any zone and I configure them as a 21=Heat Alarm.
What is the difference between heat alarm and fire alarm?

A heat alarm (thermal detector) senses a fixed temperature (usually 135 or 194 degrees) or a rate of rise (usually 15 degrees within a minute). It then closes a contact.

A smoke detector senses smoke by using either a ionization chamber or a photoelectric chamber.
I should have made my question a little clearer. What is the difference between configuring a heat sensor as a fire alarm and configuring it as a heat alarm? Does the Elk panel respond differently to fire and heat alarms?
 
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