ACSC100 No Output

[Anonymous user]

I am at my end with our ACSC100. We have had it installed in our server closet for about two years. For the first several months it worked great, then due toa failed internal component, it stopped working completely. APC responded promptly by replacing the component and all was back to normal. However, over the last year or so, performance has steadily degraded. We attributed this to two things. One, environmental conditions, we were concerned that our plenum could simply not absorb the exhaust air. And second, because of additional equipment added over the last year. Since these concerns were recognized, we have taken the steps to, exhaust the condenser air out of our plenum, and we have retired equipment no longer in use to offset the equipment added.

Nevertheless, we still cannot get the ACSC to run higher than 600 CFM and no more output than about 2.3kw in In-Row mode, and no more that 4.1kw in Spot Mode.

I have reset and checked factory defaults numerous times and have insured that we have the most current software updates.

Since we have started working on it intensively over the last few days, I have also been getting a "Persistent Low Suction Pressure" alarm causing it to shut down. Upon inspecting the unit, I discovered that when the failed component had been replaced last year, the tech had crimped both of the suction tubes between the side panel and the bar behind it. I fixed this but still am getting the alarm.

Any advice would be much appreciated. My company cannot afford a new AC unit at this time, and I am convinced this one can do what we need it to.

Michael

[Erasmus_apc]

I will be checking with our Air Support team in regards to this question, and either I or a member of their team will post shortly. If you feel you need quicker support please call 1-800-800-4272 and select the option for Air/Cooling support.

[Erasmus_apc]

Based on some discussion with our air team, the general understanding of the issue is there is a persistent low suction alarm with the existence of increased load and poor performance? Without more detailed unit status/numerical information or pressure data, the most accurate estimation of the issue is that it is probably a refrigeration-related issue. The best course of action would be to have a refrigeration tech come on side to check for any leaks in the system (system is 410a), or call APC Air Support at 1-888-695-6500 to check on any existing services/entitlements of yours.

[Anonymous user]

Erasmus, thanks for the response. I think refrigerant would be an easy solution.

Here is the current status of the unit:

Group Overview

Cool Setpoint: 72.0 °F
Supply Air Setpoint: 64.0 °F
Air Flow: 613 CFM

Maximum Rack Inlet Temperature: 81.7 °F
Minimum Rack Inlet Temperature: 81.7 °F
Maximum Return Air Temperature: 88.0 °F
Minimum Return Air Temperature: 88.0 °F

Cool Output: 2.6 kW
Cool Demand: 2.6 kW

Unit Overview

Operating Mode: On
Compressor State: On
Cool Output: 2.5 kW
Cool Demand: 2.5 kW
Rack Inlet Temperature: 81.8 °F
Supply Air Temperature: 75.1 °F
Return Air Temperature: 88.1 °F
Condenser Outlet Temperature: 110.8 °F
Condenser Inlet Temperature: 81.4 °F
Suction Temperature: 86.3 °F
Air Flow: 613 CFM
Evaporator Fan Speed: 51.1 %
Condenser Fan Speed: 40.4 %

Unit Detailed Status

Input State: Open
Output State: Closed
Filter Differential Pressure: 0.02 "WC
Suction Pressure: 114 psi
Discharge Pressure: 391 psi
Superheat Temperature: 48.4 °F

[Anonymous user]

One other additional detail. When switched into Spot mode (Discrete), the system will sharply ramp up to 1200CFM/12kw then quickly fall back down to 600CFM/4kw regardless of setpoints.

[Erasmus_apc]

Ok, well again after some discussion with our air team the amount of information and nature of the issue apparently is believed to be handled best by phone, especially if you need to discuss a site visit. That's at least the "preferred suggestion", the number is the same one I provided in my previous post.

[Anonymous user · Accepted solution]

I spoke with Cooling support and they have advised, as you did earlier, that it is likely that our refrigerant is low. I will post back with results after a recharge.