15 - How Duct Detectors Work - Introduction to Fire Alarms

I'm explaining how fire alarm systems work for new technicians or other employees who deal with these systems. This is my 16th video in a string of many Khan Academy-styled lessons. This video explains how duct detectors work.

[@MrSuper_416-jx1rs]

11 years since posted and still helps students like me. Thanks

[@jicnfpa122]

The best ever video series I found for fire alarm...amazing and outstanding job..Thanks Joe !

[@kleattomassetti6394]

Really helped me. Most videos on these are more HVAC related, and not so much fire panel related. Thank you.

[@Kenneth_H_Olsen]

I am a student myself these days. and your instructions give a fast catching up with the formal books for the Exam ! I learn alot , thanks. Fire alarm is a big thing in the electric business .

[@virtualtreadmillwalknature1488]

amazing explanation. Helping people.. Keep it up..

[@jnagel161092]

thank you very much for all of these videos

[@maheshpradhan9401]

I really liked the explanation. Thanks Joe ...keep good work

[@wildtrain]

well done as usual Joe

[@Sam-pg7nj]

These videos are awesome

[@saidajanane2146]

i cant thank u enough wow thank u so much

[@xabel3]

Thanks for the video!

[@engosamadawood]

man you are amazing

[@maxiepattie85]

good stuff, thank you

[@wichita711]

Been there thanks you mr jeo

[@Vitamin-Q]

Joe when testing differential pressure between the sampling tubes with a digital manometer... Do you take an average reading or a peak reading? I've seen some fluctuations from pass to fail.

[@aronjohn84]

And also a relay with a mmf

[@mebrn5337]

i know he's no longer around to answer. but maybe others know.. if I wanted to change the duct detector, what wires would I short together so as to keep the FACP happy and not go into alarm? can I just disconnect the power and the zone wire?

[@JoeKlochan]

I'm still around

[@aronjohn84]

Wish youd hook up the switch to it now

[@robertcortez6815]

Can the duct detector be installed on the supply or does it have to be on the return?

[@JoeKlochan]

+Robert Cortez The international building code requires them to be on the one side and the international mechanical code requires them to be on the other. I don't remember which is which. Some towns adopt IBC, some adopt IMC. I've seen them both ways, and I've also seen many buildings that have detectors on both the supply and the return.

[@tonybignell4621]

What causes the Aux Alarm relay to change state?

[@JoeKlochan]

That changes state when the detector activates, same as the regular alarm relay. It just allows for another circuit to be controlled by the detector in addition to the alarm panel.

[@maf1986mf]

Why is my duct detector keep getting full of water??

[@JoeKlochan]

Probably condensation