Ejector Troubleshooting Guide

Root Cause Overview

The ejector does not draw water because the throat fails to develop sufficient negative pressure. When motive water is sprayed through the nozzle at high speed, a low-pressure zone should form in the throat region, drawing gas or liquid from the suction chamber into the mixing and delivery stream. Once this negative pressure condition is compromised, the ejector cannot draw water properly.

Common Causes

1. Insufficient Motive Water Flow or Inlet Pressure

Inadequate motive water flow or low inlet pressure results in insufficient jet velocity, preventing the throat from generating enough negative pressure. This is one of the most common causes and is typically related to an undersized supply pump, excessive pipe resistance, or fluctuating supply pressure.

2. Inadequate Inlet/Outlet Pressure Differential

The ejector requires a certain pressure differential across the inlet and outlet to function properly — typically no lower than approximately 25%–30%. An insufficient differential indicates inadequate driving energy, making it difficult to establish throat vacuum.

3. Excessive Outlet Backpressure or Improper Installation Position

High outlet backpressure directly suppresses the formation of throat vacuum. In addition, an improper installation position — such as excessive suction lift or poorly routed outlet piping — will also impair suction performance.

4. Undersized Connecting Pipes and Valves

When connecting pipes or valve diameters are smaller than the ejector interface, piping resistance increases significantly, reducing the actual motive water flow and pressure entering the ejector and compromising its performance.

5. Pipe Blockage and Internal Clogging

Blockage of the suction pipe, ejector throat, or inlet/outlet piping by foreign objects, welding slag, or dirt is a common field cause of ejector suction failure. Construction debris and scale deposits can both contribute to localized clogging.

6. Internal Scaling Causing Dimensional Changes

After extended operation, internal scaling may develop inside the ejector, altering the nozzle and throat dimensions. Nozzle wear or scale-induced constriction changes the jet parameters, disrupting the original design operating point.

7. Incorrect Installation Orientation or Flange Stress Deformation

Installation orientation that does not meet design requirements, or excessive stress from flange connections causing component deformation, will affect the precision of the ejector's internal flow path and consequently its performance.

8. Model Selection Mismatch with System Conditions

When the ejector model does not match the actual motive water volume and pressure, the unit cannot draw water normally under the given operating conditions — even if the ejector itself is free of defects. Design parameters must be re-checked against actual field conditions.

Troubleshooting Steps

It is recommended to troubleshoot in the following order:

Step 1: Check the pump flow rate and head to confirm the water supply system meets the ejector's design operating requirements.

Step 2: Use the pressure gauges at the ejector inlet and outlet to verify the actual pressure differential and determine whether it falls below the minimum requirement of 25%–30%.

Step 3: Check whether the outlet backpressure, valve opening, and pipe diameters are appropriate, ruling out excessive backpressure or excessive pipeline resistance.

Step 4: Check whether the suction piping, throat, and inlet/outlet pipes are blocked by foreign objects; disassemble and clean if necessary.

Step 5: If none of the above checks reveal abnormalities, consider the possibility of internal scaling; shut down for disassembly and inspection, and clean according to the equipment material specifications and maintenance requirements.

Adjustment and Verification

After completing the above troubleshooting and cleaning, restart the system and observe the ejector's water suction performance. If the unit still fails to draw water after adjustment, re-check the following:

• 1. Whether the ejector model matches the current system's motive water volume and pressure
• 2. Whether the installation position and orientation conform to the design drawing requirements
• 3. Whether the overall system operating conditions (flow, pressure, temperature, media characteristics) are within the design range

If necessary, contact the equipment manufacturer for on-site technical support and model selection re-verification.

Contact Information

Company Website: https://www.cd-greenwater.com
Technical Contact Number: 028-85130135
Customer Service Contact Number: 18515915124
Contact Email: jane1984@cd-greenwater.com
Address: No. 191, Section 1, Changcheng Road, Xihanggang, Shuangliu District, Chengdu