May 2016 Tech Challenge
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A rooftop utilizing R-410A with a fixed orifice has a customer complaint of insufficient cooling. The symptoms confirm a warm building and the compressor appears to be running all of the time. What are the “possible causes” (Note: There is only one problem intended) with the following measured conditions on this field service check sheet?
Field Service Check Sheet
| Compressor Discharge Temp. | 210 deg. F. |
| Condensing Press./Temp. | 316 psig / 100 deg. F. |
| Condensing Outlet Temp. | 89 deg. F. |
| Condenser Sub cooling | 11 deg. F. |
| Condenser Split | 12 deg. F. |
| Entering Feed Device Temp. | 49 deg. F. |
| Evaporator Press./Temp. | 102 psig / 32 deg. F. |
| Evaporator Outlet Temp. | 68 deg. F. |
| Evaporator Superheat | 36 deg. F. |
| Compressor Inlet Temp. | 78 deg. F. |
| Total S. H. | 46 Deg. F. |
| Ambient Temp. | 88 deg. F. |
| Room/Box Temp. | 80 deg. F |
| Compressor Volts | 240 V. |
| Compressor Amp. Draw | Low |
Looking for the answer? Check hvac-blog.acca.org on June 30, 2016 for the answer to this Tech Challenge.
Posted In: ACCA Now, Tech Challenge
