Duct Smoke Detector question

Why a sensor in the ducts?

My gut says you will need a power source separate from the furnace. The control voltage from the furnace would then be put through the NC portion of one of the form C contacts to cut power to the furnace when smoke is detected.

Testing - push the test button as described in the data sheet.


I will echo engineered - why?

It’s required by code for a legally finished basement..

BargainHunterCan wrote: ↑ It’s required by code for a legally finished basement..

Is this multi unit?

Is that finished basement being used as a separate residence? AFAIK - If not and it is just for your own dwelling then it is not required, specifically 9.10.18.5 addresses a single dwelling, however it also addresses a building that requires Fire Alarm System. Does your dwelling fit that requirement?

9.10.18.5. Smoke Detectors in Recirculating Air Handling Systems
(1) Except for a recirculating air system serving not more than one dwelling unit, where a fire alarm system is required to be installed, every recirculating air handling system shall be designed to prevent the circulation of smoke upon a signal from a duct-type smoke detector where such system supplies more than one suite on the same floor or serves more than 1 storey.

Refer to Sections 3.2.4.12 and 9.10.18.5 of OBC

https://www.ontario.ca/laws/regulation/120332

Now I could very well be misinterpreting the OBC and I will let others, more knowledgeable, comment.

BargainHunterCan wrote: ↑ It’s required by code for a legally finished basement..

OK, so it looks like it's designed to stop the HVAC from running if it detects smoke in the ducts. Hopefully it's required to be interlocked to the other smoke alarms as well.

That’s correct, I need it as I am building a completely independent unit in the basement.

I am wondering if anyone can talk about any experience with wiring the sensor.. There are hardly any instructional videos on it online

BargainHunterCan wrote: ↑ That’s correct, I need it as I am building a completely independent unit in the basement.

I am wondering if anyone can talk about any experience with wiring the sensor.. There are hardly any instructional videos on it online

You say completely independant. I'm assuming this is not true and thst they are sharing hvac given your statement.


As per my above:

you will need a power source separate from the furnace. The control voltage from the furnace would then be put through the NC portion of one of the form C contacts to cut power to the furnace when smoke is detected.

That’s correct, I meant with a separate entrance etc.

For the separate power source.. are we talking about 120Vac or 24 Vdc?

BargainHunterCan wrote: ↑ That’s correct, I meant with a separate entrance etc.

For the separate power source.. are we talking about 120Vac or 24 Vdc?

Cut sheet for device you mentioned specifies it can be 24vac or 24vdc in terminals 9 and 10 ot 120vac to the specified terminals.

Edit: personally I would look at hardworking a 24vac transformer to your furnace shutoff switch to provide power to the detector.