Hi. I have a potential client that would like to have some sort of sensor that ties into a chiller system to let him know if the chiller has stopped operating. I think a chilled water sensor that somehow ties into a computer is what he is looking for. If the chilled water temperature rises say 3 degrees an alarm goes off and an email or page is sent. Something simple and inexpensive is preferred. Can anyone help with this? Thanks Jim
Sorry I posted this in a different forum earlier by mistake.
Try a current transducer on one of the power legs of the Chiller. That way if you lose the chiller you'll know right away. If you are going to wait for a rise in Temp it may take awhile before your client gets a reaction from his service people. The current transducer is a two wire affair and is easy to install. May need a free ai on the chiller HID if there is one or wire it back to the main BAS and find a free ai on a controller and tie it in from there. Good Luck. czkidd
You can do the same with the pumps (if there is a concern) - and can use on/off current transducers if you don't have analog inputs available. These digital units can even be used with frequency driven equipment if you spec the transducers to correct load profile.Hawkeye is my brand of choice.
Current sensors are a great device , but 1ST ? should be does your customer have a AUTOMATION system to tye them into.
Quick and simple ( without BAS already in place ) remedy would be a AQUASTAT and a AUXILLARY relay tyed into an AUTO DIALER. If temperature goes up triggers an alarm , pager is dialed , if chiller power goes off relay drops out triggers an alarm pager is dialed.
Have a # of old buildings that have no BAS and installed the above , tyed into their alarm company , alarm goes off the call the on call building operator, also have a few using auto dialers.
There are a number of ways to do this, first, does the customer have sime kind of BAS. If he does then it is as simple as attaching a pair of wires to it. I would not do the 3 degree temperature thing, cause that will cause a bunch of false alarms. I do it by looking at run status of the chiller. I have 2 old Carrier's I think 19dg's. I wired a general purpose contactor into the control circuit. Chiller run's, contacts close, digital signal is sent to BAS saying that Chiller is running, Chiller stops, contacts open, digital signal is sent that Chiller is not running. As far as the alarm, can this guy program?
I don;t know what a current sensor on the chiller would do for you in this case,
I don't understand what a current sensor on the pump would do for you either.
I think an alarm output from chiller and sending it to an autodialer or tying it into your BMS or security system is the most sensible thing.
Most chillers have alarm outputs and if it doesn't, get into the lockout circuit and monitor it,this is the best way.If you tie a sensor in you will need to be able to disable it when chilled water is not required.
If feasable install a 1\2 hour time delay before generating an alarm.
Also note that some Carrier units will lockout the chiller on a loss of flow and will not restart it when flow resumes,thats because they are idiots.
[Edited by fat eddy on 03-05-2005 at 08:56 AM]