wiring a 4 wire CO sensor

[dsiroky]

I'm trying to wire up a 4-wire carbon monoxide sensor from System Sensor.

Unfortunately, the information in the installation manual doesn't go into a lot of detail on how to wire up a CO sensor, and what zone to configure it as.

I'm using the System Sensor CO1224T detector, and I have 2 of these daisy chained to each other. 4 wires run to the first sensor, and 6 wires run from the 1st sensor to the 2nd sensor.

The system sensor wiring diagram seems to indicate that the CO sensor has it's own power supervision relay built in.
http://www.systemsensor.com/pdf/I56-3111.pdf

It also says to configure it differently to standard 4-wire smoke alarms.

It should be noted the installation, operation, testing and maintenance of ​

the CO1224T/CO1224TR is different than System Sensor conventional 4-wire ​

smoke detectors, such as the i3 Series. Below are specific installation requirements for the CO1224T/CO1224TR:​

• Connect to a non-resettable power supply​

• Connect to a non-fire zone: Per NFPA 720 section 9.6.7.2 the CO1224T/​

CO1224TR shall not be connected to a zone that signals a fire condition​

• Per NFPA 720 section 9.6.7, do not connect the CO1224T/CO1224TR on ​

a zone with other fire or intrusion initiating devices - i.e. do not connect ​

on the same zone as smoke detectors​

• Wiring of the trouble relay is mandatory: Per UL Standard 2075 section ​

17.1.1 a detector shall send a trouble signal to the control panel upon an ​

open circuit, a ground fault, sensor removal or sensor end of life​

• If wiring one CO1224T/CO1224TR per zone: Use 4 conductors​

• If wiring multiple CO1224T/CO1224TR detectors per zone: Use 4 conductors from panel to first CO1224T/CO1224TR, then use 6 conductors ​

from the second CO1224T/CO1224TR to other detectors on the zone​

My Questions.

#1 I am connecting to Zone #2. Should the jumper be in the NRM or SMK position

#2 Which wiring diagram do I follow - do I wire it up like a 4 wire smoke on Z1-4 (i.e. only use one of the zone terminals, and the other goes to switch 12V).

#3 Looking at the diagram, is this considered a normally closed circuit which opens on either power fail, or gas detection?

The above wiring information makes me think it should be configured as NRM, and wiring it like a regular 4-wire zone. If I do that, what zone type should I pick in PC Access. Fire Emergency, Gas, or Auxiliary Emergency? I would like to have it dial out if a gas leak is detected, and always be monitored regardless of arming status.

 

[dsiroky]

A bit of trial and error, and I made some progress.

The relay does appear to have it's own power supervision / trouble built in, so no need for an EOL relay, but I did include the EOL resistor.

I set the jumper to NRM, and wired it up the auxiliary 12V (contrary to the HAI manual which suggested switched 12v for a gas detector, but following the system sensor CO manual), then I wired both the zone inputs to Z+ / Z- and configured it as a zone Auxiliary Emergency.

The panel now seems to be correctly reading the status as ready.

Next step - pull the power line and verify the circuit goes into trouble mode.
Also - buy a can of CO gas to test it to ensure it's triggering correctly and the alarm.

Now if only I could work out what I am doing wrong with the Zone 1, 4 wire Smoke detector.... whenever I wire that one up according to the HAI manual, I seem to cause a Fuse Trouble status - so something is wrong with my wiring - I just haven't worked out what yet. It might be my EOL power supervision relay.

This non standard wiring on Z1-Z4 is very confusing.

 

[N49atv]

well if its fues trouble your pulling too much current. So either you have a short, bad detector, or need a larger EOL.

 

[Del91574]

Wiring would be the suspect here, assuming a proper supervision relay was being installed. Chances of a bad detector are small, not unheard of, but the wiring would be the first suspect.

Unless specifically needed by a particular CO detector, they should be on constant power, not switched. Zone should be normal and then the EOLR wired through the supervisiory contacts as shown in the documents.

 

[dsiroky]

The Co detector is working fine now on constant current, but I moved it to off Zone 1-4 so that I could correctly set the zone type to Gas.

The fire detector is also working fine. It turned out I had wired it wrong - I mis-interpreted the directions thinking I only needed 4 wires for a smoke alarm.

What I should have done, is daisy chained the smoke detectors with a 6 conductor cable, or used 6 conductor cable between the first and the last (like I did with the CO detectors), and 4 conductor cable to the smoke detector

Basically, the smoke detectors (4 in my daisy chain), use 2 wires for power daisy chained, and 2 wires for their communication bus daisy chained which controls the interlinking so that they all go off at once.

There's a 2nd set of alarm contacts on the smoke detector which I should have wired up for the alarm relay.

the communication bus and the alarm relay aren't interchangeable - I was trying to put the power supervision relay on the communications bus between the smokes.

Once I had that worked out, I had 2 choices.

1) disconnect the communication bus interconnecting them, and use the alarm relay instead (i thought this would probably violate fire code - even though the omni pro would trigger the internal house alarm, I didn't feel I could guarantee all the smokes would sound off together)

2) leave the communications bus in place for smoke interconnection, and wire it as a 2 wire smoke alarm. The omni pro can the monitor it, but the alarms will be correctly interlinked and go off and all sound when there is a fire. I did this on Zone 1 and set the jumper to SMK and it seems to work. All the alarms sound off, and the panel reads the alert status correctly.

 

[Del91574]

Sounds like a non-standard or UL listed smoke? Not familiar with a smoke that has communication lines in addition to dry circuit wiring.
I've seldom seen modern units that take more than either 2 or 4 wires unless connecting to external notification or supervisiory devices.

 

[dsiroky]

The smoke detector is UL listed, it is a System Sensor 2012J.

Here's a link: 1012 Ionization and 2012 Photoelectronic Smoke ... - System Sensor

The CO detector was also a System Sensor model.

Just wasn't great information on exactly how to wire it to a monitored panel vs a power supply

 

[Del91574]

It's odd, but the big item of contention is the unit is not supposed to be connected to a FACP or similar, but installed with a stand-alone power supply and it's looking like the circuit is designed to only to trigger the other smokes, not a panel. Also, it's not available through the US distributors, so that's another huge red flag for me.

Looks almost like a retrofit item, to allow smokes to be installed without a panel in a location that was wired for LV units originally. with no FACP being installed.

 

[dsiroky]

It's a challenge - but I've moved from Seattle to Australia, and the building codes are different. For example, the 4WTB models aren't approved by the fire department/authority here, but the 2012Js are.

In light of that I had to ensure that the system would meet building codes first, and then be able to be monitored by the panel 2nd.

I wound up with both requirements met, but would have gone with a different smoke detector if I was still based in Seattle.