Tech Challenge – July 2014
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A split air conditioner that has been retrofitted from R-22 to R-438A (M099) with a TXV metering device (and receiver) has a customer complaint of “warm, no cooling”
The condensing unit appears to be running 100% of the time. What are the “possible causes” (Note: The unit was retrofitted per the manufacturers guidelines and there is only one problem intended) with the following measured conditions on this field service check sheet?
Field Service Check Sheet
| Compressor Discharge Temp. | 220 deg. F. |
| Condensing Press./Temp. | 195 psig / 95 deg. F. |
| Condensing Outlet Temp. | 81 deg. F. |
| Condenser Sub cooling | 14 deg. F. |
| Condenser Split | 10 deg. F. |
| Entering Feed Device Temp. | 81 deg. F. |
| Evaporator Press./Temp. | 50 psig / 32 deg. F. |
| Evaporator Outlet Temp. | 51 deg. F. |
| Evaporator Superheat | 19 deg. F. |
| Compressor Inlet Temp. | 75 deg. F. |
| Total S. H. | 43 Deg. F. |
| Ambient Temp. | 85 deg. F. |
| Room/Box Temp. | 80 deg. F. |
| Compressor Volts | 240 V. |
| Compressor Amp. Draw | Low |
Check hvac-blog.acca.org in early September for the answer.
Posted In: ACCA Now, Tech Challenge
