Switch with indicator light?

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Aledrell

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I have an unusual request from a customer who owns a smoke shop. The neighboring store complains that they can smell the smoke and that the smoke shop own is not using the roof top exhaust fans as he is supposed to. Therefor the smokeshop owner wants a 120v switch with an indicator light that lights up illustrating roof top exhaust fan proper operation. Not only does he want to know through the indicator light that the motor is running he wants the light to show people air is moving in the duct. So if the belt breaks on the unit above we will not get a false indicator light showing proper operation. My thoughts include some sort of duct detector, someone mentioned a sailboat switch. Need some thoughts and opinions on this one guys, thanks in advance.:confused:
 
The technology exists. After the reactor accident at Three Mile Island, one of the required upgrades that all plants had to make was to install sound detectors in the relief valve exhaust lines, so that if a valve were to stick open, they had a diverse (i.e., different technology) detection system (other than just valve position indication) to report the fact. :smile:

Kidding aside, this is a waste of effort. Presuming you can trust the man's statement that he really does use the fan, and presuming you can trust the complaining person's statement that they can smell the smoke, then installing a light to prove the fan is on will not solve the real problem. I would bring in a ventilation contractor, and get something done about the (apparently) inadequate smoke removal system.
 
Agreed

Agreed

iwire said:
First off I agree with Charlie, they should get an HVAC person that can look at the entire situation and understand all the variables involved.

But the customer is the customer and what is often used for air flow proving is a Differential Pressure Switch.

http://www.bapihvac.com/ZPS_Pressure_Switch.htm
Click to expand...


I would agree with the both of you. The customer is not concerned with fixing the problem, he wants to prove he is using and maintaining his exhaust fans. In this economy I'll do whatever wants if the check clears, but this definately looks like an HVAC partnership venture. Also when I said indicator light I meant like the switch you typically see for a commerical walkin freezer, with toggle at the top and the orange light at the bottom. This switch will also control exhaust fan function. Thanks for your input.
 
use one of these-

http://customer.honeywell.com/honeywell/ProductInfo.aspx/S688A1007

normally they will just handle a control circuit load so you'll have to use an contactor or icecube relay depending on how big your fan is.
This type of set up does not rely on the switch that controls the fan. Also is not prone to false readings like a CT could give you if the fan did, like you mentions, not run because of a broken belt or something like that.
 
Even bagel stores by me are required not to force everyone to endure your smoke or smells in thier neighborhood and rooftop precipitators are required by code which puts a high voltage charge on plates and the smoke is attracted to the plate which can be cleaned on a regul;ar basis. Look into a precipitator system for your exhaust gasses and noone will smell smoke.
 
Aledrell said:
I have an unusual request from a customer who owns a smoke shop. The neighboring store complains that they can smell the smoke and that the smoke shop own is not using the roof top exhaust fans as he is supposed to. Therefor the smokeshop owner wants a 120v switch with an indicator light that lights up illustrating roof top exhaust fan proper operation. Not only does he want to know through the indicator light that the motor is running he wants the light to show people air is moving in the duct. So if the belt breaks on the unit above we will not get a false indicator light showing proper operation. My thoughts include some sort of duct detector, someone mentioned a sailboat switch. Need some thoughts and opinions on this one guys, thanks in advance.:confused:
Click to expand...

The sail switch, differential pressure switch and others are all good suggestions. I have a better solution that your client should thank you for. Doesn't matter if you live in a hot or a cold climate the cost of heating or cooling that make-up air that is lost to the exhaust could be sizeable. Install a speed controlled ducted fan that exhaust the air far away from the adjacecnt shop and controll it with a draft-gauge pressure transmitter. Set it to 1" or so, and it will speed up whenever the door is opened and slow down when there is no loss of negative pressure.

Sounds like one of my cigar shops.
 
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