even if you replace the manual reset pressure switch with an automatic one the liebert control has already seen the high limit and shut down on alarm. i guess you could go into the programming and adjust the alarm priority for the head pressure switch but at this point you are just messing with the design of the safety system built into the unit.
at this point i would look into the flow issues and how to fix them rather than taking a chance on completely destroying a liebert.
we have dealt with similar issues and have added a second water loop and towers to take some load off. seems these data guys racks get smaller yet more powerful creating more heat in tighter space. then they add racks with the new found space. it's a never ending battle.

what temp are they trying to maintain in the data room. we did some experimenting with a data room that had been maintained at 71* and changed that to 80*. this was a traditional room without hot/cold isle containment. the racks could easily handle the temp rise and they saved tons on cooling costs.

 

Yep, auto hp reset is a bad idea.

Is this your loop or are you tapped off a building loop ?

I believe the HP is single pole double throw opening a control circuit and also closing a switch that sends a signal back to the micro.

 

add an inline booster pump on the first floor? Those units have strainers, and are clean, correct?

 

Instead of wasting your time trying to put a bandaid on it you should solve the problem. Do you have any email or phone notification of room temp? If not it is easy and can be inexpensive to install. You can also install ICOM in all the units and then link it to sitelink, but its not cheap. There are alot of things you can do. Look into AFCOM, it is a organization for IT people that go over all aspects of a data center, you can get good info from them on local mechanical companies that will give you the options that best serve you. I could go over alot of things but not knowing what your room is setup like, I'm just pissing in the wind. Hopefully this helps

 

Bingo. No excuse in this day and age for critical environments to not be monitored 24 hrs a day by computer or phone. Sitelink is the way to go. Hell, you can even have it call the service company so your IT guys don't get bothered at 2 AM.

 

Manual HPS are installed for a reason, If you trip it you need to look at it and see why it tripped. I dont know how many compressors I have replaced because it went into high head then auto reset untill it died. It will destroy the compressor ie. cook the oil, high pressure = high tempature. It has been mentioned here already and I agree with setting up some type of room tempature monitor that will send an alarm to a phone or email. We use ALC in my data rooms, in the critical areas we use sensors in the hot and cold rows so we can prevent problems. What would happen if you did not know that your condenser water pump died and your systems all had auto HPS's? Its cheaper to get some type of monitoring installed that to replace a half dozen 06D compressors. JMO :cheers:

 

Fix the flow problem.

Then, if the data floors really mean anything, address the single point of failure in your cooling system.

 

All,

The loop issue cannot be fixed. Its not even a long term issue, its a weird anomaly that occurs due to my location in the building. Landlord refuses to fix it.

It only happens 1-2 times a year, we lose flow for about 20-30 seconds, then the flow returns. The loop is redundant, in 18 years we have never lost flow long-term. I am at the very bottom of the building, if the pumps hiccup or get hit with air bubble, the momentary loss of flow is worst for me and causes my units to trip. Once I reset, everything is back to normal.

Problem is.... if I am not here to reset, the room will over heat.

 

YOU HAVE RELIEF VALVES ON YOUR WATER OR GLYCALL CONDENSER THAT COULD RELEASE IF YOU DO THAT; I WOULD HOOK UP FLOW CONTROLE THAT IF I LOOSE FLOW MY BACK UP PUMP WOULD COME ON ,ALSO I WOULD TEST IT 4 TIMES A YEAR ..ALSO WOULD INSTALL 2 BALL VALVES TO ISOLATE IT FROM SYSTEM SO IF HAD TO BRING SYSTEM DOWN I COULD USE WATER BACK UP FROM THE BUILDING ; THIS WHAT IVE DONE ; R,S,E,S BETTER SEVICE THROUGH KNOWLEDGE;

 

You could install a differential pressure control to monitor your
Loop Flow and program the Liebert Units to shut down in the event of loss flow and restart when the flow is re-estabilished.......

 

What if you add a second, lower setting, high pressure switch with an automatic reset and time delay in series with the solenoid coil? This will pump down the compressor and shut it down before it trips the head safety. Put a 30 minute or so time delay on it so you don't get short cycle alarms.

 

We installed sensaphone systems tied right into contacts on liebert units and programmed our phone numbers in, cheap and easy notification of hi temp, excess noise, etc.