Q1: Why is the solenoid valve not responding or not working at all?**  
**A1:**  
- The control board may not be sending a proper pulse signal.  
- The power voltage may be insufficient to activate the valve.  
- The valve coil may be burned out or disconnected.  
- Internal parts may be stuck due to debris, scale, or corrosion.

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### **Q2: Why is water continuously flowing or leaking from the valve?**  
**A2:**  
- The valve is not closing properly, possibly due to:  
  - Worn or damaged rubber seals  
  - Debris or scale preventing full closure  
  - Weak or broken internal spring  
  - Valve core stuck in the open position

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### **Q3: The valve works sometimes, but not always. What could be the cause?**  
**A3:**  
- The capacitor that provides the pulse may be aging or weak.  
- There may be unstable power supply or loose wiring.  
- The valve may be partially clogged, causing inconsistent performance.

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### **Q4: The valve makes unusual noise or acts slowly. Why?**  
**A4:**  
- Mechanical resistance inside the valve due to dirt or scale buildup  
- Low voltage or weak pulse causing incomplete movement  
- Coil overheating or partially damaged

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### **Q5: How do I check if the solenoid valve coil is burned out?**  
**A5:**  
- Use a multimeter to measure the coil resistance:  
  - Normal resistance is usually between **20–50 ohms** (varies by model)  
  - **Infinite resistance** indicates an open (burned out) coil  
  - **Zero resistance** indicates a short circuit inside the coil

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### **Q6: How to maintain or repair the solenoid valve?**  
**A6:**  
- Remove and clean the internal parts with clean water or vinegar if there’s scale buildup  
- Replace damaged rubber seals or springs  
- Ensure wiring and connections are secure  
- Replace the valve if the coil is burned out or internal parts are badly worn

 

 

 

Analysis of Smart Toilet Pulse Solenoid Valve Failure**

The **pulse solenoid valve** in a smart toilet is a critical component responsible for controlling water flow for functions such as flushing, spraying, or pre-wetting. It operates by receiving a brief voltage pulse that energizes the coil and drives the valve core.

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### **1. Common Symptoms of Failure**

1. **Valve does not actuate** (no water flow / no flush / no spray)
2. **Inconsistent valve action** (works intermittently)
3. **Continuous water flow or leakage** (valve fails to close)
4. **Delayed response or abnormal sound**
5. **Valve gets hot or emits a burning smell**

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### **2. Root Cause Analysis**

#### **1. Electrical Failures**
- **No pulse signal or insufficient voltage**
  - Faulty control circuit or main board failure
  - Pulse voltage does not reach required activation level (e.g., rated DC 9V but actual voltage too low)
  - Aged capacitors unable to supply enough startup current

- **Coil burnout or open circuit**
  - Continuous power supply causes overheating and coil damage (pulse solenoids are meant for brief activation only)
  - Moisture ingress leading to short circuit, corrosion, or insulation breakdown

#### **2. Mechanical Jamming / Valve Core Issues**
- **Valve core corrosion or blockage**
  - Poor water quality, scale buildup, or debris jams the moving parts
  - Fatigued or broken internal spring fails to reset valve core

- **Damaged or aged seal rings**
  - Leads to leakage or inability to fully close the valve
  - Rubber aging due to long-term use or high-temperature water

#### **3. Installation or Usage Errors**
- Incorrect installation direction (usually marked with an arrow for water flow)
- Power supply polarity reversed
- Non-original replacement parts causing incompatibility with control board

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### **3. Troubleshooting Tips**

| Checkpoint | Suggested Action |
|------------|------------------|
| Control Circuit | Use a multimeter to measure the output pulse voltage—ensure there is a proper trigger pulse |
| Valve Coil | Measure resistance (typically tens of ohms); infinite resistance may indicate burnout |
| Valve Core | Listen for a "click" sound during activation; no sound may mean it's stuck |
| Cleaning | Disassemble and clean the valve—remove scale or debris |
| Water Pressure | Ensure water pressure is within operational range (too low or high can cause malfunction) |

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### **4. Preventive Measures**

- Use softened or filtered water to prevent scale or debris buildup
- Use quality capacitors and avoid frequent valve activations
- Regular maintenance and replacement of aged parts (e.g., rubber seals)
- Avoid prolonged energizing—pulse solenoids are designed for short bursts only