DUCT DETECTORS EXPLAINED

[@deviouslick5097]

The best HVAC teacher on KZbin.

[@MrResinrider]

You explain things very well ! I've been in this trade for 20 years and still learn something every time I watch one of your videos! Thanks!!

[@nightone9720]

DUDE, you explained this super well. Thank you!!!! WOW!!! You should be an instructor at a college when you get too old to do service anymore when you are older. I think you would be the best instructor of all time.

[@bobfeng5360]

Your videos are better than learning in the hvac school,you’re the best teacher I’ve ever seen!

[@anklee71]

As a control personnel dealing with JCI, Siemens and other.. This was a great video to explain to me about the fire smoke detectors. I always just leave it alone since I am always afraid to touch it due to life safety. Now I can just verify that it is not my problem and it is a fire personnel problem. Also, now I can understand what my fire control contractor is talking about in their annual troubleshot testing. Thanks for the explanation. Ankle

[@anklee71]

Question: when my fire control person stated that they has to remove the head off to reset the alarm.. What does that mean to me? Is the old smoke detector does not have the remote reset/test panel? Is it the cover?

[@MrWaynesea]

You do an excellent job explaining how these devices operate. You also offer encouragement for those who may not be familiar with many functions of the detector.

[@usbowler716]

This was fantastic knowledge thank you for this component breakdown. As a technician in training, all of your explanation videos are sure to help me thrive as a tech!

[@jdamx_0000]

LOVE those explanation videos. usually learn a lot from your on field videos but man i want more of these too. thanks!!

[@andrewedis9907]

Thankyou I don't do much duct work and this helps.

[@majbummer69]

I've learned more from watching your videos than from several college professors combined. I don't even work in HVAC.

[@watermanone7567]

Good explanation. The last school that I did required both dedicated phone lines and wireless antenna to operate the fire alarms. Many thanks.

[@snowballinflatableandgaming]

I didnt know you knew so much about fire alarms. As a person with a fire alarm hobby i can verify you know more then the average human.

[@HVACRVIDEOS]

I know a little bit too much about a bunch of stuff

[@snowballinflatableandgaming]

@@HVACRVIDEOS Same lol. I have wayyyyyyyyyyyyyyyyyyyyyyyyyy to many hobby were i am really nerdy in.

[@guy872]

Very informative video Chris! I work in the fire alarm business and never thought to see something on here that ties directly into what I deal with. I usually just enjoy your troubleshooting methods as there is some cross over but seeing this topic covered was awesome! Your explanations of everything was very simple to understand and spot on. I always had a hard time wrapping my head around the trouble/supervisory contacts and the way you described the operation helped it finally click. Many thanks for all the great content!

[@AaronCo29]

Ryan McKay I actually come from an alarm background, and here in this area I’m in, with HVAC, after explaining how this one works and why, I usually still have that, “deer in headlights” look and the two places I worked before going out on my own, it was said a lot of times, just send Aaron, he knows those things. I’ve even suggested watching KZbin and guys like Chris to do some self training and the arrogance astounds me, I’ve come to nickname it, “Redneck Mentality” and I’ve seen it in both sides of this fence, we actually had fire alarm techs that didn’t understand a supervisory circuit as well.

[@chriscooley906]

Thank you Chris, This was a great in depth description of the operations and functions GREAT WORK, I appreciate all the time you take to share your knowledge Thanks again

[@brendanmichaelwelsh6260]

This is also a great explanation that can be applied to Alarm systems, They work the same way./

[@arthouston7361]

This is the setup used now for factory detectors for Lennox units, whether they arrive on site with the detectors installed, or in an SD kit for installation into the same type of RTU because the sales guy never included detectors in his proposal, and now YOU have to make it all work once the installation crew leaves, after placing stickers in the units showing their smiling faces. Yes, NAS actually does that. Here is a warning: Lennox does not do a complete checkout of the wiring in the unit on the assembly line, so you can find that the SD setup is not working as intended once you put it all together. The fault is the mis-placement of conductors in the unit harness connector bodies. You need to correct this with a connector tool, placing the correct wires into the correct opening in the connectors. FYI...don't be surprised if you have to "fix" a brand new unit.

[@James_Bowie]

Regarding the 'tweaker' theft alarm, that's a good idea in principle but the fire alarm monitoring company we use rates supervisory/fault alerts as low priority, and we'd be lucky to get even an email about them. They consider such alerts to be something that the fire service contractors deal with during their monthly service calls, when they are supposed to check out the panel for any fault alerts showing. If that were an issue at our site, I'd have rooftop perimeter security in place to alert the security company to trespassers.

[@Cleofizoid]

The "Supervisory" relay is a Normally Energized relay. So with power applied to the detector and no Trouble condition, the Supervisory contacts are in the opposite state of what's silk screened. The Supervisory/Trouble relay must be normally energized or "Fail-Safe" by code to properly signal Trouble in the event of duct detector power loss.

[@sebastiannielsen]

This is EXACTLY why you always need to MEASURE. Not just trust labels. Same with magnetic door contacts. Some magnetic door contacts are labeled in the state without the magnet attached, so if wiring up the magnet to a burgular system, you need then to think in the opposite way. Other companies label the magnetic contact as with the magnet attached, so you need to wire accordingly with the label. Best way to avoid any trouble - use your trusty multimeter! Same here, some circuit boards for duct detectors label their supervisory relay with power applied, which would mean you would have to think "normally". So multimeter is the only way to be 100% sure. The problem is the definition of "normal". Is "normal" the state it is in when you unbox it out of its shipping packaging, or is "normal" the state when it is, when its installed in a properly working system? Different manufacturers define it differently, so just pick up your multimeter and measure your way to success.

[@bobcasseus7381]

Best training video ever WOW very good explanation and clear!

[@CrownRider]

Excellent explanation. Thanks. Smoke alarms on the air inlets should trip the air handling system in order to avoid sucking in smoke from the outside. Smoke alarms on the air outlets should activate the evacuation alarm panel and/or the fire alarm panel. In Europe a short or break in the cable to a fire detector should initiate a fault condition on the fire panel. Besides an "end of line resistor" the alarm zone therefore also has an "alarm resistor". It is a bit more complicated and lot's of installation mistakes can happen. The trouble relay is mostly a "power-on" relay when no active fault detection or automatic self-test is involved.

[@Robyrob7771]

Thx for the video! Clarified a lot of things for me.

[@Ronnocbot]

Fire alarm systems have always been a huge hobby of mine. Your videos got me into HVAC. It's really cool to see them both come together. System Sensor is a brand I'm very familiar with.

[@FireTech7]

Ayyyyy

[@sebastiannielsen]

Also some systems use a double end-of-line resistor, one in series with the alarm contact, and one parallel, to be able to differentiate a fire condition to a wire that is severed such as it is shorted (shaved against for example a sharp metal plate or similiar). Then 0ohm is a trouble(short), 15kohm is a fire, 30kohm is normal operating, and inf is a trouble(severed wiring). This is more common for burgular systems however, but some systems, especially systems that are designed to work either as fire or burgular, can act like this.

[@bob_c2997]

The reason you supervisory contacts are "backward" is because they are power supervised. The alarm wires go in and out of the alarm contacts. The neg of the alarm goes to the common of the SPV contacts and the EOL goes from the NO terminal to the pos of the alarm contact. This way, if the DD should lose power, the alarm contacts still work but the SPV will cut the EOL out of the loop and cause the fire panel to report a trouble. Typically you would daisy all DD alarm wires and then send them back through the SPV contacts in series putting the EOL on the last one so all alarm contacts will trip but any SPV will put the circuit in trouble. I am a fire tech and have been for years.

[@nilborne1]

You will want to call alarm company and have them put system in test mode before shutting off disconnect if using RTU transformer. Found that out the hard way. Good explanation!

[@j.r.1223]

Helps to keep the instruction with the unit. Good info.

[@harrydickson4575]

Excellent explanation. 👍👍👍

[@JuanTodoli]

Good explanation Chris 👍

[@brianmcdermott1718]

Great subject and description. Thanks, Chris

[@RayRay-nb7tn]

Great explanation of how the detector operates. In a hospital setting, it is set to the FD notification of a direct short= fire potential/ then enunciaters and strobes. You didn't touch on the filter that goes in there? We usually use Honeywell. Installed many of these. On final inspection we do a smoke test that operates with fire/ smoke combo dampers that close on alarm to many. Like you said it can operate just about anything you want IT'S ALL ABOUT HOW YOU WIRE IT AND CODES.thank you for the video and explanation of this. Great job.

[@HVACRVIDEOS]

Thanks for watching Ray, I plan on talking about the filter on the livestream this evening....

[@RayRay-nb7tn]

Thank you I will tune in and watch, been trying to relax my wife as she is on the front lines in the ER.

[@ikehvac30]

Very informative Chris, I learned quite a bit from this video. Keep it up.

[@mikeashton249]

Just a suggestion from what I see in your videos. You’d be a great teacher.

[@James_Bowie]

You read the manual? You're definitely supervisor material. 👍

[@andygalindo8978]

This is gold.

[@HVACRVIDEOS]

I have a few more if you just search duct detector on my channel and or on KZbin they will come up

[@rickmarchand5033]

You should show how it interfaces with shutting down the HVAC unit. Some interupt the thermostat common hot wire and some other equipment have a terminal(s) on their control boards for a form C relay to control the HVAC equipment depending what was activated; full alarm, trouble or supervisory.

[@iuliandobrin]

I Like you’re video, you are the best teacher!

[@ghwizz]

Where did you get that super cute small fluke that you put above the panel? I want one!

[@Ted_E_Bear]

Great job !

[@leokumarg8104]

Hi smoke detector auxiliary contact A we can use 240VAC stop AHU

[@jordanhenshaw]

Okay so this might be why my building’s fire alarm has been in a Trouble mode for months. I shut down an indoor FCU unit because I condemned it (still waiting on contractor to replace it). So maybe it was wired to put system into Trouble when that is powered down. Interesting. Will investigate tomorrow.

[@mikeashton249]

Wyo tech would definitely need you. Just a suggestion

[@andrewmcdonald3411]

Have had a lot of dead shorts on the smoke bases on those detectors, you have to be careful on the current as well, forget how much those contacts can take to actuate power Dampers,

[@goalie2998]

Usually the contacts are for control circuits only. The contacts have a very low current rating.

[@rickmarchand5033]

I'm in New Hampshire and it depends how the AHJ wants the action of the detector from town to town. Some AHJ want the presents of smoke to go into full alarm, where other AHJ want the presence of smoke to activate a supervisory condition and simply shutting down the equipment to lessen the spread of smoke being moved around from fans. how the detector and it's relay base is most generally accomplished in the programming of the FACP. Also, in NH and the NFPA fan control are not required for anything under 5 tons of AC which is about 1750CFM of air volume. 350/ton. Does Cal. follow these guidelines?

[@FireTech7]

I think you should buy a little panel like a Fire-Lite MS-4. Then you could hook up all your devices and get the troubles and supervisories and alarm conditions

[@kelvinmorris1938]

Makes sense why the trouble condition is n/c. Bc it’s a safety. Like how pressure switches in a schematics are shown n/c.

[@Ronnocbot]

What model are the smoke heads within the duct unit by the way? 2151?

[@palamidi13]

We thank you for that video!

[@HVACRVIDEOS]

You bet! I will be going live on KZbin this evening 4-20-20 @5:PM (pacific time) to discuss my most recent uploads and answer questions from comments, the live chat, and emails come on over and check it out if you can. kzbin.info/www/bejne/bGOqZntrpKaebq8

[@frankjackson2439]

Ah, so that’s what’s been hanging up behind you.

[@Tommy_boy007]

I have a duct detector at a gymnastics facility. All the chalk in the air trips the duct sensor. Fun times 🙄

[@AaronCo29]

Tom sounds like a really great time, especially trying to figure it out

[@j.r.1223]

Smart twickers- funny.

[@ryanstanford6172]

How does an event venue set up duct sensors to not go off with haze, fog or other atmospheric effects? Most churches and theaters are able to run haze without tripping fire alarms and no fire marshal monitoring a disabled system.

[@sebastiannielsen]

Some fire alarms have a "Pause" function (atleast here in sweden). Usually a timer button located in the event area, or a mechanical clicky timer. You push it or turn it to the time you want to run the event, and it will "silence" the zone in the prescribed time. It works like "Home" and "Away" arming in a burgular system works, where "Home" bypasses all inner zones. in many homes for the ederly, kitchens do have such a "Pause" button, so you can pause the alarm during food cooking, so not the fire brigade is summed just because youre cooking. These "Pause" or "Silence" function can work in a multitude of different ways, and sometimes in combination. For example. - A detector might have 2 sensitivity settings, where the "Pause" or "Silence" puts the sensor in the higher mode. Another, a "Pause" or "Silence" might put the alarm into a "local mode" where it will not call the fire brigade, but it will simply go off the local sirens. It can enable a delay, that means the alarm will not call the fire brigade if its resetted within a specific delay. It can also completely silence that particular zone, practically disconnecting it completely. Some fire alarms also have a "Occupy" input like many of the HVAC units. This can be wired either to a motion detector, or the best: Wire it inverse to a burgular alarm's "armed" output, so when the burgular alarm is disarmed from the code panel, the building is marked as occupied in both the fire alarm and HVAC units, and in the same way, when burgular alarm is armed from the code panel, the building is marked as unoccupied and air units etcera can go into power saving mode. If theres no burgular alarm, but a night lock or "extra lock" on the front door - wire up that to the building occupy signal. When the night lock is unlocked, building is occupied. When the night lock is locked, building is unoccupied. This occupy signal on fire alarms can control the delay in the same way, so if the building is marked as unoccupied, any alarm will immidiately be sent to the fire brigade, and any silence/pause timers are ignored (all zones active forcefully) while if building is occupied, there will be a delay of usually 1-3 minute before the alarm is sent to the fire brigade so if you reset in that time, its ok, and same with silence/pause timers, they have effect. In this way, if someone would forgot to turn off the pause timer, and then go home, a fire that happens shortly after closure but before pause timer has expired would still be detected, as the building is marked as unoccupied, and the pause timer is ignored.

[@chipethecat]

Sebastian Nielsen Even residential smoke alarms have an temp silence mode now.

[@mikeashton249]

You should apply too be a teacher at Riverside Community College. I sense that’s your passion. Too teach refrigeration and hvac. Just a suggestion you would be a great teacher for the new comers in the trade. They need your help.

[@mikeashton249]

I’ve got an awesome idea it’s just a suggestion if you want too hear it just message me.

[@HVACRVIDEOS]

give me your email and or send me an email [e-mail]

[@adamhvacr6536]

So if you have a small cigarette lighter and you hold it near it Will it go off and shut off the exhaust fan too?

[@jeremyhundley3142]

Not unless there is a heat head, which is different than a smoke head :-)

[@snoopyjc]

Ohhhhh - it’s a duck detector! :-) 🦆

[@jordanhenshaw]

I am so confused. I’ve been staring at this for 5 minutes straight and I still have no idea what I’m looking at. Why is the meter cut in half vertically?!?!

[@jordanhenshaw]

I found it on Google. Apparently it’s a “remote display meter” and the top part sort of slides off the body. Looks super trippy in a video without context though lol.

[@HVACRVIDEOS]

Ha ha yeah it’s an older model that work perfectly for training

[@kjetilpp]

Simple, RTFM :)

[@mrgreen2646]

These things can be a bitch to put on in a commercial setting

[@johnfrye3368]

My bosses first question to anyone that calls him for tech support: "Did you read the installers guide?"

[@michaelcollier6390]

boom First..

[@rickmarchand5033]

The remote test and status device should never be field altered to accommodate other manufactures equipment. Once you alter the device you just destroyed the UL rating of that unit.