InRow RP Compressor Starting Up Every 5 Minutes

[Anonymous user]

I have a small data center consisting of:

Rack 1 - Radio control cabinet
Rack 2 - Battery rack
Rack 3 - Symmetra 20K
Rack 4 - Inrow RP
Rack 5 - Network/Switch cabinet, with ISX Management Module, Ethernet switch and various switches, bridges and routers.
Rack 6 - Server cabinet, with 6 servers, 5 rackmount, one freestanding on a shelf.

Rack 5 and 6 have temp sensors located on the front doors.

Group Setpoints:

Cool Setpoint and Supply Air are at 68 F
Humidify Setpoint is 45 % RH
Dehumidify Setpoint is 55 % RH
Dehumidify Deadband is 5 % RH
Reheat Setpoint is 64 F

Config is set to InRow

The InRow RP is cooling as it should, even moreso than expected. I am trying to determine why the compressor in the unit starts up about every 5 to 10 minutes. I've been told that the open spaces in each equipment rack need to be sealed off completely (we're getting the 200 piece airflow managment panel kit soon) to reduce the amount of cool air coming back into the InRow RP.

Any chance of reducing this startup and wear on the compressor, or will sealing the room a bit better and installing the airflow management panels reduce this occurrence?

Thanks,

Matt

[TheNotoriousKMP_apc]

Hi Matt,

I asked one of our ISX Cooling team members to take a look at the thread yesterday (Friday the 20th). They're a little busy so apparently the gentleman did not get back to me in time before the end of my shift. I will shoot the entire team an email Monday (the 23rd) and see where we get.

[TheNotoriousKMP_apc · Accepted solution]

Matt,


Not sure if you're still lookin' for a reply, but one of our cooling techs was gracious enough to leave me an email pertaining to this:



The Inrow RP needs to be given a constant heatload of at least 10-12kW. If there is empty rack space without blanking panels, the cold air flowing to the hot aisle will reduce the heat load that the RP is given. With the supply air and cool setpoints both at 68F, you will likely see very high fan speeds. In the Inrow configuration, the supply air setpoint controls the temperature of the air the unit supplies to the cold aisle with compressor control. The cool setpoint controls the fan speed based on the maximum rack inlet temperature. The higher the rack inlet temperature is, the higher the fan speed will be (relative to the cool setpoint). These 2 setpoints should typically be 3-7F apart. In low load situations, the optimal setpoints often differ based on the specifc room configuration.


I would recommend setting the cool setpoint between 72-74F and monitoring the unit performance, adjusting the cool and supply air setpoints as needed. You can also enable the heat assist function. This will enable the unit to use the heater to help prevent excessive cycling (this can be enabled under "configure unit" on the front display or from the web interface under the unit tab, then the configuration section). Changing these settings and installing blanking panels will definitely help prevent cycling, but if the load is still too small then you may still have cycling issues. If you won't be getting blanking panels soon enough, you can use anything to block the airflow as a temporary blanking panel. If the compressor cycles 12 times within an hour it will go into an excessive compressor cycling alarm that has to be cleared manually. Regardless of whether or not it goes into the alarm, if you notice a large amount of cycling it is not good for the compressor life as you expected.




If you have any further questions on this, I would recommend contacting the Cooling ISX Tech Support Team via phone.