Exhaust Fan and Actuator
Exhaust Fan and Actuator
(OP)
We just replaced an existing dishwasher exhaust fan (utility set) with an uplast 2500CFM at 3.5" ESP. We installed a motor operated damper in the curb adapter so when the fan starts up the damper opens up. This was an internal mounted fast acting actuator 120V. Since the owner wanted to use existing electrical and not run any new circuits (cost), we pulled 480/3/60 from the disconnect to a transformer (Nema 4) and then 120V from the transformer to actuator. The owner wants the actuator on the curb exterior, not a big deal find an actuator with nema 4 enclosure. Well I cannot find a Nema actuator that is fast acting, the quickest is a 75s run time. Now besides ordering the actuator with an auxillary switch and putting in a relay prior to the fan starter so when they turn on the fan it will not start till damper is open.
Anyways would it be fine if I use a 75s run time actuator? So when fan turns on the actuator starts opening the damper. Will this "hurt" the fan or motor? The factory initially sent it with a 25s fast acting actuator with no auxillary. Thanks!
Anyways would it be fine if I use a 75s run time actuator? So when fan turns on the actuator starts opening the damper. Will this "hurt" the fan or motor? The factory initially sent it with a 25s fast acting actuator with no auxillary. Thanks!





RE: Exhaust Fan and Actuator
Might be noisy as heck when the damper first cracks open.
RE: Exhaust Fan and Actuator
Are you trying to avoid wind rattle from airblast/gravity operated dampers?
B.E.
The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor
RE: Exhaust Fan and Actuator
RE: Exhaust Fan and Actuator
Backdraft damper has the advantage of not failing so often as a motorized damper, especially in a wet environment, nema 4 enclosure or not.
RE: Exhaust Fan and Actuator
RE: Exhaust Fan and Actuator
I also took pictures of what we did so I can send them to you.
RE: Exhaust Fan and Actuator