Michaelmechanic
Member
- Location
- Ft lauderdale fl Lu 728
Is it unusual for an exhaust fan in a commercial building bathroom to be wires on 24/7
Exhaust fan
- Thread starter Michaelmechanic
- Start date
- Status
fmtjfw
Senior Member
- Location
- Fairmont, WV, USA
Is the building occupied 24/7?
Michaelmechanic
Member
- Location
- Ft lauderdale fl Lu 728
No. The lights are on a sensor but not the fan.
- Occupation
- Licensed Electrician
Not typical but not unprecedented either.
I know of two places I work on regularly that have bathroom exhaust fans that run non-stop. When they quit it soon becomes apparent right why they run all the time. Bad plumbing maybe.
- Location
- Massachusetts
If they have floor drains pour some water down them, the water in floor drain traps evaporate when not used regularly allowing sewer gases out the pipe.
- Occupation
- Licensed Electrician
Dammit Jim! I'm an electrician, not a water boy.
- Location
- Illinois
- Occupation
- retired electrician
I have installed a couple of timer operated solenoid valves to prevent that problem. They were both for floor drains in a hospital.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
The plumbing code calls for special intermittent low flow valves called trap primers for this type of floor drain. It is used with an air gap to prevent back siphoning.
If no air gap, it would be a violation.
- Location
- Illinois
- Occupation
- retired electrician
I don't know how the plumbers connected it, I just hooked up 120 volt power and I was done with my part.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
I've run into the 24/7 fart fan issue before, and it is sometimes done by the HVAC folks as an issue related to air exchange regulations and air balancing issues. So don't change anything unless you check with them first, you can get things really screwed up.
How I came to know this is that I put timers on some in an office building at the request of the owners when doing some retrofit work on VFDs, seemed reasonable to me. But by those fans not running and exhausting all the time, the minimum speed setting on the building supply fans ended up pressurizing the building and the inward opening doors could not be opened. People panicked, called the fire dept, who broke glass doors to let them out! (Nobody realized in the panic that any of the automatic sliding doors would work fine, and the main front door opened out). I got hit with the bill for it but luckily I had the email from the building owner authorizing me to do it.
How I came to know this is that I put timers on some in an office building at the request of the owners when doing some retrofit work on VFDs, seemed reasonable to me. But by those fans not running and exhausting all the time, the minimum speed setting on the building supply fans ended up pressurizing the building and the inward opening doors could not be opened. People panicked, called the fire dept, who broke glass doors to let them out! (Nobody realized in the panic that any of the automatic sliding doors would work fine, and the main front door opened out). I got hit with the bill for it but luckily I had the email from the building owner authorizing me to do it.
Michaelmechanic
Member
- Location
- Ft lauderdale fl Lu 728
I was thinking maybe they run because the want to make sure there's no fumes left. Like In a janitor closet that has chemicals or bathroom for obvious reasons
Last edited:
Michaelmechanic
Member
- Location
- Ft lauderdale fl Lu 728
I'm sending an rfi. Good to have documentation
- Status