Possible deviation from specification | Possible causes of fault | Fault elimination |
l
| High pressure increases above specification |
l
| Low pressure quickly drops to value in graph or below |
l
| Required cooling output is not attained |
| Constriction or obstruction in refrigerant circuit | –
| Run hand over refrigerant circuit to check for differences in temperature |
l
| If difference in temperature is found at one component: |
–
| Renew hose or pipe if kinked or constricted. |
–
| In the event of clogging, clean refrigerant circuit (flush with refrigerant R134a → Chapter or blow out with compressed air and nitrogen → Chapter). |
–
| Clean refrigerant circuit (flush with refrigerant R134a → Chapter or blow out with compressed air and nitrogen → Chapter). |
|
l
| High and low pressure normal at first |
l
| After some time, high pressure increases above specification and |
l
| low pressure drops to value in graph or below, |
l
| Required cooling output is no longer attained |
| Moisture in refrigerant circuit | –
| Check and if necessary renew reservoir (with dryer) and restrictor, then evacuate refrigerant circuit for min. 3 hours (see note) |
–
| Clean refrigerant circuit (flush with refrigerant R134a → Chapter or blow out with compressed air and nitrogen → Chapter). |
|
l
| High and low pressure normal at first. |
l
| After lengthy operating period, low pressure drops excessively (evaporator ices up). |
| | |