# Troubleshooting {% hint style="info" %} When the flow meter shows an abnormal condition, users can follow this page for basic troubleshooting. Most issues can be resolved on site without returning the unit to the factory or waiting for technical support. If the issue is not listed below or cannot be resolved: * Use parameter [**H06**](/qr/fp-as310-english-v5/parameters/h-system/h06-reset.md) to restore factory settings. * Repeat the setup process ([mechanical installation](/qr/fp-as310-english-v5/installation-and-setup/mechanical-installation.md), [electrical installation](/qr/fp-as310-english-v5/installation-and-setup/electronic-installation.md), and [parameter settings](/qr/fp-as310-english-v5/installation-and-setup/parameter-setup.md)). * If the problem persists, refer to the **“**[**Advanced Support Procedure**](#advanced-support-procedure)**”** at the bottom of this page and provide a photo of the debugging screen(Status Page) to the manufacturer.. {% endhint %} ### **Common Issues and Self-Troubleshooting** #### 1. Abnormal Measurement Results
Q1-1. Unable to Measure Flow (No Flow Display on the Screen) If the main unit does not display flow data, please follow the steps below to troubleshoot: **Check Installation and Pipeline Conditions** * **Ensure Full Pipe:** Verify that the sensor is installed at a fully filled section of the pipe. Avoid mounting at the highest point or on downward vertical sections. * **Eliminate Air Bubbles:** If air may be present in the pipeline, purge the air or relocate the sensor to a more stable section without trapped air. * **Verify Flow Direction:** Ensure the flow arrow on the sensor matches the actual fluid flow. If installed incorrectly, reinstall the sensor in the correct direction. **Confirm Actual Fluid Movement** * **Activate Pump or System Flow:** Make sure the fluid is actually flowing. * **Test at Higher Flow Rate:** Very low flow may not generate a detectable signal. Increase the flow rate to see if the measurement displays correctly. **Equipment Specification Limits** * **Below Minimum Flow Range:** If the actual flow is below the minimum measurable range of the flowmeter model, the main unit may not display data to maintain accuracy.
Q1-2. Flow Displayed as 0 If the flow meter displays 0 under conditions where flow should be present, check the following: **Verify Pipe Type Setting** * **Check Parameter** [**A01 (Pipe Type)**](/qr/fp-as310-english-v5/parameters/a-measure-setup/a01-pipe-type.md)**:** Confirm that the pipe type setting matches the actual pipe fitting installed. An incorrect pipe type will cause the meter to misinterpret the paddlewheel rotation and may result in a zero or incorrect reading. **Check Installation and Pipeline Conditions** * **Ensure the pipe is fully filled:** An empty pipe or partial fill will prevent the paddlewheel from rotating correctly. * **Eliminate air pockets:** Air in the pipe may prevent the paddlewheel from spinning even when liquid is present. Purge the air or relocate the meter to a section with stable, full-pipe conditions. **Verify Flow Velocity** * **Check if flow velocity is above 0.3 m/s:** The FP-AS310 has a minimum measurable velocity of **0.3 m/s**. Readings below this threshold are displayed as zero by design. This is not an error — verify that the actual flow velocity in the pipe section is above the minimum threshold. *** **Foreign Objects (for intermittent zero only)** If the flow velocity is adequate but the reading still drops to zero intermittently, a foreign object may be causing the paddlewheel to slow or stop. 1. **Stop system operation.** 2. **Drain any remaining liquid** from the pipeline. 3. **Remove the main unit** from the installation. 4. **Detach the paddlewheel assembly** and inspect for foreign objects. Remove any debris found. 5. If the paddlewheel is **missing or damaged**, contact your sales representative to purchase a replacement. 6. **Identify and eliminate the root cause** to prevent recurrence.
Q1-3. Flow Reading Repeatedly Drops to Zero If the flow reading is not consistently 0 but intermittently drops to zero and recovers, check the following: **Flow Velocity Near the Minimum Threshold** * **Check the current flow velocity** on the main screen. If the velocity is frequently near **0.3 m/s**, the paddlewheel may not be able to sustain continuous rotation — causing the reading to bounce between a value and zero. * Increase the flow to bring it reliably above 0.3 m/s. If the flow rate cannot be increased, consider selecting a **smaller pipe fitting** to raise velocity for the same volumetric flow. **Foreign Objects Causing Intermittent Obstruction** * If the flow velocity is well above 0.3 m/s but readings still drop to zero intermittently, a foreign object may be causing the paddlewheel to slow or stop occasionally. 1. **Stop system operation.** 2. **Drain any remaining liquid** from the pipeline. 3. **Remove the main unit** from the installation. 4. **Detach the paddlewheel assembly** and inspect for foreign objects. Remove any debris found. 5. If the paddlewheel is **missing or damaged**, contact your sales representative to purchase a replacement. 6. **Identify and eliminate the root cause** to prevent recurrence.
Q1-4. Flow Displayed Despite System Shutdown In principle, paddlewheel flowmeters should not display flow once the system has shut down. If a small flow reading persists after shutdown, it is likely because the fluid inside the pipe has not yet fully come to rest. * **Wait for the fluid to settle:** After shutting down the pump or system, it may take a short time for fluid movement inside the pipe to fully stop. The reading should return to zero once the flow has completely ceased. * **Check for leaks or valve issues:** If flow continues to be displayed for an extended period after shutdown, verify that all valves are fully closed and there are no leaks allowing slow fluid movement through the pipe.
Q1-5. No Signal (Display Shows "No Signal" or "Noisy Signal") If the system cannot receive a stable ultrasonic signal, follow these steps: **Install on a stable flow section** * Avoid locations near pumps, valves, elbows, or other flow-disturbing components. * Ensure at least **10D upstream** and **5D downstream** of straight pipe length (D = pipe diameter). **Select the proper installation angle** * Horizontal piping with stable flow is preferred over vertical piping. * On horizontal pipes, install the sensor on the **pipe side (\~90°)** rather than on the top or bottom to reduce bubble interference. {% hint style="info" %} #### Impurity Limitations This ultrasonic flow meter operates by transmitting ultrasonic signals through the fluid and measuring the transit time difference to calculate flow.\ If the fluid contains a high concentration of solid impurities, signal stability may be affected. In such cases, consider alternative measurement methods. {% endhint %}
Q1-6. Measurement Inaccuracy (Discrepancy Compared to Other Flow Meters) **Laboratory vs. Field:** LORRIC products are calibrated in ISO 9001-certified laboratories. While laboratory conditions allow control over all variables, actual field conditions can cause a consistent offset between the meter's reading and the true flow value. This is not a malfunction, it is a normal characteristic that can be corrected. **Common causes of reading discrepancy:** * **Incorrect pipe type (A01):** Ensure the pipe type setting exactly matches the installed fitting. Different pipe sizes have distinct calibration curves — even a single size off will cause a systematic error. * **Installation conditions:** Ensure there is sufficient straight pipe **upstream (10D)** and **downstream (5D)**. Turbulent flow near elbows, valves, or pumps introduces measurement error. * **Fluid properties:** The FP-AS310 is calibrated with water. Fluids with significantly different viscosity or density may produce a consistent offset. **Recommended Adjustment:** Use **A02 Scale Factor** to fine-tune readings: $$\text{A02 setting} = \frac{\text{Target Value}}{\text{Current Display Value}}$$ **Example:** Target value = 10, actual reading = 8 → A02 = 10 ÷ 8 = 1.25 After setting, re-measure to verify that the display value closely matches the target. **Note:** A02 Offset is intended for minor adjustments only. It **does not replace proper installation or piping conditions** and should not exceed the meter’s specified measurement tolerance.
Q1-7. Reading Fluctuates Unstably If the flow rate fluctuates and causes unstable measurements, adjust the [**A04 Damping**](/qr/fp-as310-english-v5/parameters/a-measure-setup/a04-damping.md) to smooth the readings. Increasing the damping coefficient reduces measurement fluctuations.
*** #### 2. Installation and Wiring Issues
Q2-1. Incorrect Wiring Connect the device according to the wiring diagram, ensuring the correct phase and voltage to avoid errors. **Symptoms:** * If the display turns yellow, this may indicate a hardware or power issue. Stop operation immediately and inspect the system. **Warning:** * Always follow the manual for wiring instructions. * Incorrect power connection can permanently damage the internal board. Such user-caused damage is **not covered under warranty**.
Q2-2. Display Completely Blank This flow meter only supports **24V power supply**. Using a voltage other than 24V may cause the backlight to turn on while the screen fails to display properly. Always use a power source that meets the device specifications.
Q2-3. Repeated Power Cycling If the flow meter repeatedly powers on and off, the power supply may be unstable. Please verify that the voltage and current are within the device specifications. This flow meter requires **DC 24V** power input.
*** #### **3. Communication and Data Reading**
Q3-1. Modbus Incorrect Value Display To ensure correct data reading, the client PLC engineer must follow the settings below.\ **Byte Order:** The device uses **Big-Endian** format (high byte first). ![](/files/vmLMikNDSKJERdCkvTpm)
Q3-2. RS485 No Response on RS485 Communication If the device does not respond over RS485, and the PLC or host system cannot read data, follow these steps: 1. **Check Wiring According to Installation Guidelines:** * Brown wire: 24 VDC (+) * Blue wire: 0 VDC (−) * Black wire: RS485 (B−) * Green wire: RS485 (A+)
2. **Verify Communication Parameters:** * **E04 (Modbus ID):** Ensure the device ID matches the PLC/host configuration. Avoid duplicate or incorrect IDs. * **E05 (Baud Rate):** Confirm the transmission speed matches other devices on the bus. 3. **Address/Device Conflicts:** * Make sure only one device uses the same ID on the bus to prevent conflicts. **Tip:** Unstable RS485 signals are often caused by poor wiring. Check connections according to the wiring recommendations to ensure proper signal quality.
Q3-3. Analog Current Signal (4–20 mA) Not Outputting If the 4–20 mA analog signal is not being output, follow these steps: 1. **Check Wiring According to Installation Guidelines:** * Brown wire: 24 VDC (+) * Blue wire: 0 VDC (−) * Purple wire: 4–20 mA (+)
2. **Verify Function Settings:** * Ensure that **Function E06 (Iout Def.)** is enabled to activate the analog output.
Q3-4. Abnormal Analog Current Output (4–20 mA) If the analog current output value is abnormal or requires fine adjustment, check the following items step by step: **1. Excessive Loop Resistance or Load Impedance** * Verify that the wiring resistance and the input impedance of the receiving device do not exceed the specified limits. * If necessary, increase the external supply voltage to raise the allowable total loop resistance. **2. Incorrect Output Parameter Settings** * **E06 (Analog Output Definition / Iout Def.)**\ Ensure the analog output function is enabled. * **E07 (4 mA Value) / E08 (20 mA Value)**\ These parameters define the lower and upper measurement limits corresponding to 4–20 mA.\ Confirm that the configured flow range matches the intended output scaling. * **E09 (Analog Error Value)**\ Check the analog output mode or polarity setting to ensure compatibility with the controller’s input requirements. * **E11 / E12 (4 mA Fine Adjustment, µA)**\ Used for fine calibration of the output signal to correct small offsets and accurately match the target measurement value. * **E13 (Analog Output Range)**\ Line load compensation or output mode setting.\ Ensure the configuration provides stable output and sufficient drive capability for external devices.
*** #### **4.** Paddlewheel and Sensor Issues
Q4-1. Paddle Wheel Abnormality (Alarm A – D01) If **Alarm A Bit 0** is active and the LCD backlight is flashing red, the device cannot detect paddlewheel rotation. Follow the procedure below: **Inspect the Paddlewheel Assembly** 1. **Stop system operation.** 2. **Drain any residual liquid** from the pipeline. 3. **Remove the main unit** from the installation. 4. **Detach the paddlewheel assembly** and inspect the paddlewheel condition. **If the paddlewheel is missing or visibly damaged:** * Contact your sales representative to purchase a **replacement paddlewheel assembly**. **If the paddlewheel appears intact:** * Use the **H05 Paddle Init** function to recalibrate the paddlewheel. * If H05 returns **"Init. Failed Paddle Error"**, the paddlewheel is no longer functional and **must be replaced**. **After replacement:** 5. **Identify and eliminate the root cause** of the failure (e.g. foreign matter, magnetic interference, excessive wear). 6. After installing a new paddlewheel assembly, use **H05 Paddle Init** to initialise the new paddlewheel before returning the unit to service.
Magnetic Field Interference (Alarm A) If **Alarm A Bit 1** is active, a strong magnetic field near the device is interfering with the **AxleSense** paddlewheel sensing. **Remove the Source of Interference** * **Remove any equipment** near the paddlewheel that may generate magnetic fields — such as motors, electromagnets, or other high-field devices — until paddlewheel operation returns to normal. * **Keep the device away** from strong electromagnetic fields during installation. Refer to the installation guidelines for recommended clearance. **If the source cannot be eliminated:** * If the interference source cannot be removed and the flow data is confirmed to be accurate, you may proceed to **disable the Magnetic Interference alarm notification** via the D parameter group. {% hint style="warning" %} The **AxleSense** ceramic axle used in the FP-AS310 is sensitive to external magnetic fields. Ensure the installation site is free from strong permanent magnets or variable-frequency drives nearby. {% endhint %}
*** ### **Advanced Support Procedure** If the issue is not covered in the common troubleshooting section, or the problem persists after following the provided instructions, please prepare the following information and contact the manufacturer for assistance. This will help us diagnose the issue more efficiently. **Support Email: ** Please provide the following information: 1. **Version and device serial number** (please attach a photo) 2. **Status Page Screenshot** (please attach a photo) Use the arrow keys to navigate the main screen and locate the Status Page.\ If the page is not visible, go to parameter **H10** to enable the debug screen. 3. **Issue Description** * Occurrence timing: At startup / During operation / After shutdown * Reproducibility: Every time / Intermittent / One-time * Frequency: Daily / Weekly / Random 4. **Operating Environment** * Fluid / Medium: Liquid, chemical name * Temperature / Pressure range * Pipe diameter / Installation orientation / Straight pipe conditions 5. **Actions Taken** * Refer to the Common Issues & Self-Troubleshooting section on this page. ## Trouble shooting | Message or Symptom | Possible Cause | Solution | | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Error of paddle wheel |


  1. Paddle damaged by foreign objects or external force
  2. CommentShare feedback on the editorMagnet demagnetization caused by the environment.
|

  1. Stop the system operation.
  2. Drain any residual liquid from the pipeline.
  3. Remove the main unit from the installation.
  4. Detach the paddlewheel assembly and inspect the condition of the paddlewheel.
  5. If the paddlewheel is missing or damaged, please contact your sales representative to purchase a replacement paddlewheel assembly.

  6. If the paddlewheel appears intact, the issue may be due to demagnetisation caused by environmental factors. In this case, use the H05 function to recalibrate the paddlewheel.

    • If the H05 function returns “Initialisation Error”, the paddlewheel is no longer functional and must be replaced.
  7. Identify and eliminate the root cause of the paddlewheel failure (e.g. foreign matter, magnetic interference, or excessive wear).
  8. After installing a new paddlewheel assembly, use the H05 function in the settings menu to initialise the new paddlewheel.
| | Magnetic field interruption | There is magnetic field interruption around the flowmeter. |

Please remove any equipment near the paddlewheel that may generate magnetic fields until the paddlewheel operation returns to normal.

If the source of interference cannot be eliminated, and flow data is confirmed to be accurate, you may proceed to disable the related alarm notification.

| | Analogue Current Signal Not Outputting | Abnormal wiring | Please make sure that the 4-20mA loop provides power supply as well as the polarity of cable connection is correct or not. | | | The function is not turned on | Please go to [parameter E06](/qr/fp-as310-english-v5/parameters/e-commute.md) to turn on the function. | | Abnormal Analogue Current Output | Outputted value needs to be fine tuned. | Please adjust output current value by set-up parameter [E11 and E12](https://docs.lorric.com/qr/fp-as310-english-v5/pages/ttLcWqfWtCNqj9xWItVh#e11-4ma-adj.-ua-4ma-output-adjustment-in-microamp-4ma-wei-diao-ua). | | | Excessive Line and measuring impedance |
  1. Please verify whether the impedance of the wiring or the input resistance of the controller's receiving end exceeds the allowable limit for proper operation. | |
    If necessary, consider replacing the component with one that meets specification.
  2. You may also increase the external supply voltage, as a higher supply voltage can raise the maximum allowable total line resistance.
| | | | | Wrong set-up outputted parameter | Please confirm the correction of set-up parameter [E06 E07 E08 E09 E11 E12 E13](/qr/fp-as310-english-v5/parameters/e-commute.md) | | RS485 Unable to receive response. | Communication Parameter Configuration Error | Please confirm the correction of set-up parameter [E04 E05](/qr/fp-as310-english-v5/parameters/e-commute.md) | | | Address conflict | Please confirm that there is only one piece of equipment at a specified address | | RS485 signal is unstable | Poor wiring | Please refer to the [wiring instrucions](/qr/fp-as310-english-v5/installation-and-setup/electronic-installation.md) to confirm the wiring is correct | | Other abnormalities | |
  1. Please use Parameter H06 to restore factory default settings.
  2. Then, use Parameter H05 to reinitialise the paddlewheel.
| ## **Abnormality shooting** | Phenomenas | Possible Cause | Solution | | ------------------------------- | ------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | Flow volume is repeated as zero | Unable to keep rotating paddle wheel caused by too slow flow speed |

Please use the main screen to verify the current flow velocity.
If the velocity is below 0.3 m/s and the reading frequently returns to zero, there are two recommended solutions:

  1. If possible, slightly increase the flow velocity to bring it above the minimum measurable threshold.

  2. If increasing flow is not feasible, enable Parameter A08.

    • This function will reduce measurement responsiveness, but it will also minimise occurrences of zero readings at low flow rates.
| | | Foreign objects will cause Intermittent deceleration |

  1. Stop system operation.
  2. Drain any remaining liquid from the pipeline.
  3. Remove the main unit from the system.
  4. Detach the paddlewheel assembly to inspect its condition, and remove any foreign objects if present.
  5. If the paddlewheel is missing or damaged, please contact your sales representative to purchase a replacement paddlewheel assembly.
  6. Identify and eliminate the root cause of the paddlewheel malfunction to prevent recurrence.
| | Intermittent shutdown problem | Unstable power supply | Please confirm supply voltage and current is within the range. [wiring instrucions](/qr/fp-as310-english-v5/installation-and-setup/electronic-installation.md) | --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.lorric.com/qr/fp-as310-english-v5/troubleshooting.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.