| Phenomenon | Reason | Treatment Measures |
| Indicates zero or very small movement | 1. The balance valve is not fully closed or leaking. | 1. Close the balance valve and repair or replace it with a new one. |
| 2. The high and low-pressure valve at the root of the throttling device is not open. | 2. Open the high and low-pressure valves. | |
| 3. The valve and pipeline between the throttle device and the differential pressure meter are blocked. | 3. Flush the line, and repair or change the valve. | |
| 4. The vapor guide tube is not completely condensed. | 4. Wait for complete condensation and then turn on the meter. | |
| 5. The liner between the throttle device and the process piping is not tight. | 5. Tighten the bolt or change the pad. | |
| 6. Internal failure of differential pressure meter. | 6. Inspection and repair. | |
| The indication is below zero | 1. Reverse connection of high and low-pressure piping. | Check and connect properly |
| 2. Reverse signal line connection. | Check and connect properly | |
| 3. Severe leakage or rupture of high-pressure side piping. | 3. Change the parts or change the pipe. | |
| Low indication | 1. The high-pressure side piping is not tight. |
1. Check and eliminate leaks. |
| 2. The balance valve is not tight or not closed tightly. | 2. Check, shut down or repair. | |
| 3. High-pressure side pipeline air is not purged. |
3. Exhaust the air. | |
| 4. Differential pressure meter or secondary meter zero position is out of adjustment or dislocation. |
4. Check and adjust. | |
| 5. The throttling device and differential pressure gauge are not matching and do not meet the design requirements. | 5. Replace the matching differential pressure meter. | |
| High indication | 1. The low-pressure side piping is not tight. |
1. Check and eliminate leaks. |
| 2. Air accumulates in the low-pressure side line. |
2. Exhaust the air. | |
| 3. The pressure of the vapor is lower than the design value. |
3. Correction according to the actual density. |
|
| 4. Zero drift of differential pressure meter. |
4. Check and adjust. | |
| 5. Throttle device and differential pressure gauge do not match. |
5. Replace the matching differential pressure meter. |
|
| Large fluctuations in indications | 1. The flow parameters themselves fluctuate too much. |
1. High and low-pressure valves are properly closed. |
| 2. The pressure measuring element is more sensitive to parameter fluctuations. |
2. Properly adjust the damping effect | |
| Pointer does not move | 1. Frost protection facilities fail, and the differential pressure gauge and the hydraulic pressure inside the guide tube freeze. |
1. Strengthen the effect of anti-freezing facilities. |
| 2. The high and low-pressure valves are not open. |
2. Open the high and low-pressure valves. |