(2) InRow SC unusual activity when set to 'InRow'

[BillP]

Hello,

We have two InRow SC's in a group with the latest firmware (3.5.6 / 3.6.1). When we change the Configuration type to In-Row from Spot (InRow Seems much more efficient and quiet), the units hit the cool point of 72, then they allow the room to rise back up to around 78 before beginning to work again? Am I missing something with this setup? This is our 'Spot' configuration:

Group Setpoints

Cool Setpoint: 72 °F [64.4 to 78.8]
Cool Deadband: 1.8 °F [0.0 to 18.0]
Supply Air Setpoint: 61.0 °F [51.8 to 73.4]
Capacity Control: Proportional

Fan Speed Preference: Medium
Fan Speed Control: Automatic

With the settings above we are getting this sort of overview:

Group Overview

Cool Setpoint: 72.0 °F
Supply Air Setpoint: 61.0 °F
Air Flow: 2297 CFM

Maximum Rack Inlet Temperature: 71.1 °F
Minimum Rack Inlet Temperature: 71.0 °F
Maximum Return Air Temperature: 76.4 °F
Minimum Return Air Temperature: 76.3 °F

Cool Output: 10.2 kW
Cool Demand: 10.2 kW

---

Like I said, when I change from 'Spot' to 'InRow' the two units just seem to not work as intended. I'll even receive this message below:

04/08/2009 13:04:21 InRow SC: Supply air high temperature violation exists.
04/08/2009 13:01:38 InRow SC: Supply air high temperature violation no longer exists.

then the unit will cool to 72'.

Help?

Thanks in advance!!!

Greg

[BillP]

hi,

They have changed the way the logic of the cooling works in the In Row setting. The unit will ramp up and down to meet demand so their old thresholds may be set off when the unit is simply idling. Putting it into Spot more or increasing their threshold should rectify the issue.

[BillP]

Ok, I thought there might be something wrong with it and I might damage the unit. Do you think I should just stick with Spot? I am trying to keep the fans from running so loud.

Greg

[BillP]

per my cooling source..

If you want to control fan speed, you will need to use the Spot mode. InRow is more efficient but we do not always have perfect application settings and as such we have multiple configurations to meet customer needs. If Spot does the job and meets your noise requirements, then Spot mode should be used.*

[BillP · Accepted solution]

Interesting. I'd think that Spot would be louder, and In-Row quieter?

Thanks for the info!