March 2017 Tech Challenge
Posted on:
An R-410A rooftop system with a fixed orifice has a customer complaint of insufficient cooling. The symptoms confirm a warm building and the blower and 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. | 243 deg. F. |
| Condensing Press./Temp. | 431 psig / 122 deg. F. |
| Condensing Outlet | 100 deg. F. |
| Condenser Sub cooling | 22 deg. F. |
| Condenser Split | 42 deg. F. |
| Entering Feed Device Temp. | 85 deg. F. |
| Evaporator Press./Temp. | 143 psig / 50 deg. F. |
| Evaporator Outlet Temp. | 59 deg. F. |
| Evaporator Superheat | 9 deg. F. |
| Compressor Inlet Temp. | 65 deg. F. |
| Total S. H. | 15 deg. F. |
| Ambient Temp. | 80 deg. F. |
| Room/Box Temp. | 82 deg. F |
| Compressor Volts | 240 V. |
| Compressor Amp. Draw | High |
Looking for the answer? Check hvac-blog.acca.org on April 28, 2017 for the answer to this issue’s Tech Challenge.
Posted In: ACCA Now, Tech Challenge
