Freshman year of high school we had a kind of "prom" style party for freshmen only and they had fog machines that went off every so often for specific songs... well the duct detector threw a fit and set off the fire alarms lol at least we knew they worked but it stopped the party for about an hour while fire crews double checked to make sure it wasn't something else
HVAC Tech here. Great video and demonstration! What probably happened about the air handler not shutting down was most likely because of the variable speed blower motor, which stays on for 90 seconds after the call for cooling/heating/fan is no longer calling, on most Tranes (American standards) this does occur and on other brands too.
@@nics-systems-electric Variable speed or ecm/x-13 motors have their own separate board inside the actual motor, if the air handler still has power going to the legs it still will run no matter if the board lost power. They run 90 seconds after 24v power has been disconnected (voltage from the 24 volt thermostat line), unless if the high voltage 240v power is disconnected as well
You may need to change to a relay that interrupts the high voltage to the HVAC unit to ensure shutdown. Great content. Fire alarm system looks good. Still anticipating the video on the garage link.
Yes that's what I've done so it now kills power to the primary side of the transformer and the power directly to the blower motor that will be the video on Saturday
Great video! Doing tests like this helps to see where the system still needs improvement. I work in production and can defiantly verify that fog machines set of fire alarms. Its always a fun time when we have to evacuate the place because someone went to heavy on the fog haha.
the reason why they say supply air is to prevent the furnace from spewing smoke into the living space if it catches on fire or the core starts leaking combustion gasses
Yeah I understand that if it's a gas furnace this is pure electric though so it doesn't pose as much more of a risk than fan forced heaters for my location duct detection is only required if a AHU supplies multiple levels or zones so is purely just for the spread of smoke
You may have already figured it out but on these blower motors there is a signal wire or wires that come from the board you're interrupting power to; and a 24 volt that is the "G" terminal from the stat or in your case the EIM below your duct detector. I'm guessing if you're taking away board power but not all of the control power the motor will just not change its status or be able to vary the speed. I still recommend interrupting the 24 volt secondary on the trans or using the S/D terminals if they exist and it's practical. But I'm sure you've already whipped it.
Hey Nic, I noticed since the last Duct Detector test You installed what appears to be a Honeywell Wireless Thermostat System, I wonder if that's why your experiencing your issues.
ECM motor in the furnace may stay in its' last configuration when power to the board is dropped... you might have to break R between the thermostat and the board to eliminate the call for fan (I assume you have FAN on the thermostat to on). EDIT: Simpler to put both of the wires off the right terminal on the 24V transformer on the load side of the fire relay (IIRC, you only interrupted one of them (power to the board),
Never mind on the transformer... just went back and looked, and it was one of the primary side connections that I thought was paired with the red wire... I'd break R between the board and the thermostat.
That might work if I had a conventional thermostat however it's a wireless thermostat where it just is two wires for power but will still communicate if that power is dropped
@@nics-systems-electric So the wireless radio is built into the furnace? (I do commercial HVAC, not residential...) All of the wireless stats I've dealt with had a radio that connected to the furnace like a standard stat.
@@nics-systems-electric According to American Standard's applications guide, break the R wire between that module and the furnace board, and it should shut down. (youtube won't let me post the link to the applications guide)
Definitely not it's just circulating air through the house and it's not humid anyways maybe it's different in other parts of the world I don't know but I do know it's not a problem here
@@SDPP992 i'd have to look there's 14 different wires coming out of the wireless control board that communicates wirelessly to the thermostat either way it's not in a convenient place to tie into
Hey nic I got a great idea, why don't you connect both fire alarm system's together and when one fire alarm system turns on the other turns on. Your system will be extra safe like middle schools with portables. Do you agree.
Yes I did they are tied together to put each other into a non-latching supervisory but they can't put each other into alarm as an alarm condition is always latching and you would have to reset both systems which is difficult to do without it re-setting off another one so it ends up like a dog chasing its own tail if you get what I'm saying
