Smoke alarm vs code in Omni Pro II

[PaulD]

In a different thread, I discussed the new house delima I ran into related to 2 wire smoke alarms connected to my HAI Omni Pro II. After multiple emails to HAI, discussions with my alarm wiring installer, local building inspectors, I came to the conclusion that I may be technically correct but I was in a battle I would lose. The code requires that an alarm be heard in each sleeping area but does not require a sounder in each room. However, "common industry practice" is to put a smoke alarm with sounder in each sleeping area to insure inspectors are happy.

As a result, I am having my installer put another very basic alarm panel (DSC PC1616) in my house where I will only use it for one function to control the smoke alarms so every alarm sounder will sound off if any one triggers. Obvious overkill but necessary to get past inspectors.

I am posting this as an alert to others who may find themselves in a similar situation. If you are installing an HAI Omni Pro II system, here are some items to be aware of:
1) The Omni Pro II does support 2 wire smoke DECTECTORS. However, the detectors are only there to detect smoke and not to make any noise directly. The alarm comes from your alarm circuit once a dectector has dectected smoke. If you look closely at the approved smoke dectectors for the Omni, you will discover that they do not contain any sounding device. I missed that point until it was too late.
2) Other versions of the approved detectors often include options for sounders but in emails to HAI tech support, they confirmed that their board does not include any provisions to drive the sounders on multiple connected smoke alarms when any one is triggered.

I made the erroneous conclusion in the begining that since the Omni supported 2 wire smokes, I was OK. Obviously that was bad conclusion. It also is very dissapointing to me that the Omni fails to support this feature which appears to be common in other systems typically installed in homes by professional installers.

 

[CDC]

We use 4wire audible base detectors and a DPDT Reversing relay. (System Sensor RR mod. I think.) When the alarm sounds, the panel triggers the relay to sound all the bases on the circuit. It works just like the 120v smokes.

 

[CollinR]

Yeah the designer for him used 2 conductor wire and had both 2WTBAs and thermals on the same zone.

 

[Digger]

You can never use thermals or pull stations on the same circuit as converntional 2 wire smoke detectors with sounders built in as the thermal would be a dead short across the siren if the thermal was to trip.

Most mfg of the reversing modules state that in their instructions.

I think the installer goofed but maybe I am missing something in his logic.

 

[PaulD]

I think the installer goofed but maybe I am missing something in his logic.

Installer did not goof...I did. He told me up front that he was going to install 2 wire and I told him that was OK since I saw that 2 wire was supported by the Omni Pro II. I failed to recognize that the OPII 2 support was for detectors only with no function to drive sounders in smoke alarms. His wiring approach was the same he uses when he installs DSC alarm panels. In that scenerio, he mixes smoke alarms (with thermal dectectors) and plain thermal dectectors in the same loop. Thermals go in kitchen and garage.

I can make it work but it is causing me a few extra headaches.

 

[Digger]

I think the installer goofed but maybe I am missing something in his logic.

Installer did not goof...I did. He told me up front that he was going to install 2 wire and I told him that was OK since I saw that 2 wire was supported by the Omni Pro II. I failed to recognize that the OPII 2 support was for detectors only with no function to drive sounders in smoke alarms. His wiring approach was the same he uses when he installs DSC alarm panels. In that scenerio, he mixes smoke alarms (with thermal dectectors) and plain thermal dectectors in the same loop. Thermals go in kitchen and garage.

I can make it work but it is causing me a few extra headaches.

So how are you going to have thermals and the smokes with sounders on the same 2 wire zone?

 

[PaulD]

So how are you going to have thermals and the smokes with sounders on the same 2 wire zone?

I do not know other than they claim to do it routinely with a DSC panel (PC1616). Smoke alarm model 2WTA-B and thermal model 5300 all both made by System Sensor. Both units have a 135 degree thermal detector (.... smoke alarm also functions as a thermal detector). I am assuming if a thermal detector is triggered, the alarm panel would treat it just as it would a smoke alarm if the smoke alarm thermal fuse was triggered.

In my simple view, I am thinking that the thermal dector functions the same as the smoke alarm but without the smoke feature or the sounder. If it does not work, I am sure the home inspectors will throw a flag.

Side note...I think a lot of concerns on this issue have been related to a thermal detector shorting out the circuit when it is triggered. I am not sure on this point but I think I heard them say that the thermal has a NC circuit via a solder joint and at 135 degrees the solder melts and opens a circuit which can be detected by the fire panel.

After the dust settles on this, I will report back on what happened.

 

[Digger]

So how are you going to have thermals and the smokes with sounders on the same 2 wire zone?

I do not know other than they claim to do it routinely with a DSC panel (PC1616). Smoke alarm model 2WTA-B and thermal model 5300 all both made by System Sensor. Both units have a 135 degree thermal detector (.... smoke alarm also functions as a thermal detector). I am assuming if a thermal detector is triggered, the alarm panel would treat it just as it would a smoke alarm if the smoke alarm thermal fuse was triggered.

In my simple view, I am thinking that the thermal dector functions the same as the smoke alarm but without the smoke feature or the sounder. If it does not work, I am sure the home inspectors will throw a flag.

Side note...I think a lot of concerns on this issue have been related to a thermal detector shorting out the circuit when it is triggered. I am not sure on this point but I think I heard them say that the thermal has a NC circuit via a solder joint and at 135 degrees the solder melts and opens a circuit which can be detected by the fire panel.

After the dust settles on this, I will report back on what happened.

An open on a fire circuit is a trouble. A short is an alarm. Ask the installer to demonstrate the thermal to you in the circuit while he is there and before you pay him (my opinion only). See if the sounders in the detectors work.

I just dont want you to have a problem if god forbid you need this to work someday.

 

[CollinR]

The used single use thermals, I listed part#s in the other thread that both didn't have obvious markings and where resettable and hence easily testable with a hairdryer.

Also they are NO switches with EOL installed across them just like a 2 wire smoke.

 

[CDC]

Are there no spare wires anywhere to add a new heat detector zone to the HAI and be done with it? That is another reason as installers we always pull 4-conductor FPL. We have had carpenters/drywallers drive a nail through a conductor and still been able to configure a solution. It is more expensive but, it is life safety after all.

 

[Digger]

Either we are all missing something or the installer does not understand how the 2WTA-B works and that you can not mix thermals on the same 2 wire zone. I have tested the 2WTA-B extensively a few years ago and I am currently testing a new similar type of detector from another mfg. Currently in the middle of writing the installation instructions for the detector and reversing module and I am very clearly stating that you cannot put a thermal detector or pull station on the same zone as these detectors.

If a smoke detector goes off everything will work correctly. If a thermal trips the sounders will not sound and depending on where the power from the siren is being taken may disable other devices. The panel will dial our though as that is a basic requirement for any UL panel to not be affected by a short on a external connection that could affect the dialer (other than the phone line being shorted).

 

[PaulD]

Either we are all missing something or the installer does not understand how the 2WTA-B works and that you can not mix thermals on the same 2 wire zone. I have tested the 2WTA-B extensively a few years ago and I am currently testing a new similar type of detector from another mfg. Currently in the middle of writing the installation instructions for the detector and reversing module and I am very clearly stating that you cannot put a thermal detector or pull station on the same zone as these detectors.

If a smoke detector goes off everything will work correctly. If a thermal trips the sounders will not sound and depending on where the power from the siren is being taken may disable other devices. The panel will dial our though as that is a basic requirement for any UL panel to not be affected by a short on a external connection that could affect the dialer (other than the phone line being shorted).

I will get back with the installer and make sure I understand what he is doing. He is a reputable installer in my area and routinely installs systems for new construction. It is very possible that I have not picked up on some angle of the installation. I do know he has the wire in a single loop because I checked on that before they closed the walls. No components installed yet. I will get with him and see about putting the smoke and thermals on a seperate loop. In my case, I am pretty sure the loop runs thru all the smokes and then the 2 thermals are the last 2 devices at the end of the loop. Since the last thermal is in the garage and the wire is easy to access from the open attic, he should be able to run a new 2 wire to the garage thermal and then run the 2 thermals on a new loop while terminating the original loop at the last smoke.

I am convinced we will get it worked out in the end. My dissapointment is that I did not pick up on this issue early in the game. If I had, I would made him run 4 wire which would have alowed me to deal with this issue more effectively.

I really appreciate your responses and your concern about making sure I get a proper installation. Thanks