BACKUP PACKAGE AC UNIT FOR SERVER ROOM GOING OFF BY MORNING

[raven22]

IM WORKING ON A SERVER ROOM AC SYSTEM WHICH HAS A CONTROL BOX WITH PRIMARY AND BACK UP SWITCH AUTOMATICALLY SWITCHES TO BACKUP WHEN PRIMARY GOES DOWN SO THE PRIMARY IS DOWN BAD COMPRESSOR WAITING FOR NEW ONE I HAVE UNIT AIRHANDLER AND CONDENSOR ITYS A SPLIT SYSTEM AIR COOLED SHUT OFF AT DISCONECT SWITCHED OVER TO SECONDARY SYSTEM PACKAGE AIRCOOLED UNIT RUNS GOOD PROBLEM IS IT WILL NOT SHUT OFF RUNS CONTINUEOUSLY HAS ACCUTEMP SENSOR T-STATS ALL CHECKED OUT WORKS ALL DAY NO PROBLEMS CUSTOMER SAYS THEY FIND ROOM HOT EVEY MORNING PRESS BUTTON TO RESTET BACK TO PRIMERY SYSTEM THEN BACK TO SECONDARY AND IT WORKS ALL DAY UNTIL IT GOES OFF IN THE NIGHT AGAIN OUT OF IDEAS THE ONLY THING I THINK IS HAPPENING IS THE UNIT IS CONTINUEOUSLY RUNNING AND TRIPPING THE INTERNAL OVERLOADS ANY THOUGHTS WILL BE BACK THERE IN THE AM NEED SOME IDEAS

[welling service]

What button are they pushing? Take your caps lock off. All caps are hard to read. Is this button a manual change over switch from primary to secondary system? Is there some kind of timer on this system?

[raven22]

yes its a manual change over switch from primary to secondary,it seems like there is a timer but i check system did not see one

[beenthere]

Could be its going off on low pressure switch at night.

What have you checked.

[raven22]

Yea at night low ambient control working could it be going off on low pressure from unit running non stop

[viceman]

http://www.partsguy.com/cgi-bin/PartsGuy/JB12016.html

[raven22]

cool went there this morning unit still running room 65 temp unit didnt shut off had to bypass control switch over box add t-stat back up unit turning on and off fine found that though the control box when i reset unit contactors were chattering only getting 12 volts pushed in contact and all pulled in now showing 24 volts did this over and over once i switched to t-stat from control box no more voltage drop so for now this is how its going to work think i solved the problem need to tear into that switch over box and go through all the wires for possible short

[bearfromobx]

http://www.partsguy.com/cgi-bin/PartsGuy/JB12016.html

I prefer the Diversitec 007 control checker http://www.diversitech.com/Product-S...000000JpCt9IAF

It's reusable, works from 24 to 460V controls and has been reliable for everything I've used it for (I usually use a baggie and a cable tie if I suspect it might be exposed to water).

[welling service]

Not trying to be mean, but would please use punctuation like periods and such. It's hard to tell where your sentences sentences begin and end. I am glad that you are making progress with your problem.

[raven22]

oh buddy if i wanted an english lesson i would have asked mo

[raven22]

update problem fixed,the problem was the back up system was wired where on a call for cooling during switchover all four contactors where getting pulled in at the same time causing a voltage drop,the blower moter,condensor fan motor,and cooling stage one and two,was causing contactors too only pull halfway in most of the time causing arking,so i added a couple delay on makes,and its working great

[bearfromobx]

update problem fixed,the problem was the back up system was wired where on a call for cooling during switchover all four contactors where getting pulled in at the same time causing a voltage drop,the blower moter,condensor fan motor,and cooling stage one and two,was causing contactors too only pull halfway in most of the time causing arking,so i added a couple delay on makes,and its working great

Isn't it amazing how the simplest things can cause the most problems and take the longest to find!