How to repair urinal flush valve?

Common faults of urinal flush valves include weak/no flushing, continuous water leakage, and sensor failure (for sensor models). Repair for different types (manual push-button and infrared sensor) mainly focuses on "component inspection → fault location → replacement and repair," requiring no complex tools. Specific steps are as follows:

I. Preparations: Tools & Safety Operations

1. Essential Tools

Basic Tools: Adjustable wrench, screwdriver set (flathead/Phillips), needle-nose pliers

Consumables: Replacement parts (compatible gaskets, O-rings, solenoid valves; confirm flush valve brand/model in advance, e.g., TOTO/Kohler dedicated parts)

Cleaning Supplies: Clean cloth, white vinegar (for descaling)

2. First Safety Step: Turn Off Water & Power

• Turn off water: Close the "angle stop valve" under the urinal or on the wall (turn clockwise to fully close). Press the flush button/trigger the sensor to drain residual water in the pipeline, avoiding leakage during repair;

• Turn off power (sensor models only): Unplug the power cord of the sensor panel (for battery-powered models, open the panel and remove the batteries) to prevent electric shock.

II. Type-Based Repair: Manual vs. Sensor (Common Fault Solutions)

(I) Manual Push-Button Flush Valve: Focus on "Mechanical Components"

Most faults of manual models are caused by seal aging, valve core blockage, or spring failure. Focus on inspecting water inlet, drain channels, and sealing structures.

Fault 1: No Flushing/Weak Flushing After Pressing

Judgment Basis: No resistance when pressing the button, or resistance but no water flow/weak water flow.

Repair Steps:

1. Remove the button and valve body:

• Unscrew the button cover on top of the flush valve (some are snap-on; gently pry the edge with a screwdriver to remove), then take out the internal spring and valve core;

• Use a wrench to unscrew the connecting nut between the valve body and the water inlet pipe, and remove the entire valve body.

2. Clear blockages:

• Check the "water inlet filter screen" of the valve core (usually at the bottom of the valve body). If clogged with limescale or sediment, soak it in white vinegar for 10 minutes, then rinse thoroughly with clean water;

• Unclog the "drain channel" inside the valve body (use a thin iron wire or special unclogger to remove impurities, avoiding scratches on the inner wall).

3. Inspect the spring and gasket:

• If the spring is deformed or loses elasticity, directly replace it with a spring of the same specification;

• Check the "sealing gasket" (black rubber pad) at the connection between the valve body and the water inlet pipe. If damaged/aged, replace it with a new gasket (note the front and back of the gasket; the convex side faces the water flow).

4. Reassemble and test:

• Reinstall the valve body, valve core, spring, and button in the reverse order of disassembly. Open the angle stop valve, press the button to test the flushing effect. It is normal if there is no leakage and the flushing force is adequate.

Fault 2: Continuous Leakage After Flushing (Leakage from Water Inlet/Drain Outlet)

Judgment Basis: Leakage stops when the angle stop valve is closed, or water continuously seeps from valve body gaps or the urinal edge after flushing.

Repair Steps:

1. Locate the leakage point:

• If leaking from the "valve body and water inlet pipe connection": Check if the sealing gasket is misaligned, damaged, or the connecting nut is not tightened (use a wrench to tighten moderately clockwise, avoiding thread breakage);

• If leaking from the "gap between the valve core and valve body": Remove the valve core and replace the "O-ring" outside the valve core (common specifications: diameter 10-15mm, thickness 2mm; must match the valve core size).

2. Replace seals:

• Completely replace aged seals (gaskets, O-rings). Before installation, apply a thin layer of "silicone-based grease" on the surface of the new seals (to avoid poor sealing due to dry rubber; do not use engine oil as it will corrode rubber).

3. Test sealing performance:

• After reinstallation, open the angle stop valve and observe for 10 minutes. If leakage persists, check if the valve body has cracks (if cracked, the entire flush valve needs to be replaced).

(II) Infrared Sensor Flush Valve: Focus on "Sensor and Electronic Components"

Faults of sensor models are divided into "sensor issues" (no flushing trigger) and "mechanical issues" (weak flushing/leakage). First distinguish between electronic and mechanical faults.

Fault 1: No Response to Sensing (No Flushing Trigger)

Judgment Basis: No indicator light (or red light on) when hand approaches the sensing area, and no flushing action.

Repair Steps:

1. Check power supply:

• For plug-in models: Check if the power plug is loose and if the socket is powered (use a multimeter to measure the socket voltage; normal voltage should be 220V);

• For battery-powered models: Open the sensor panel (usually on the top or side; unscrew the fixing screws with a screwdriver), take out the batteries, and check for leakage or insufficient power (replace with new 1.5V AA batteries, noting the positive and negative polarities).

2. Clean the sensor probe:

• If the "infrared probe" inside the sensor panel is covered with dust or limescale, it will cause sensing failure. Wipe the probe surface with a dry cloth dipped in white vinegar to remove stains (do not wipe directly with a damp cloth to avoid water ingress and short circuit).

3. Inspect the solenoid valve:

• If the power supply is normal and the probe is clean but flushing still does not work, the "solenoid valve may be clogged/damaged":

1. Remove the solenoid valve (located on top of the valve body, connecting the sensor module and valve body), and rinse the "valve core" inside the solenoid valve with clean water (if stuck by impurities, it will fail to open);

2. If ineffective after flushing, use a multimeter to measure the solenoid valve coil resistance (normal resistance should be 100-300Ω; if resistance is 0 or infinite, the coil is burned out, and the solenoid valve of the same model needs to be replaced).

Fault 2: Weak Flushing/Continuous Leakage After Sensing

Judgment Basis: Weak water flow after sensing trigger, or continuous water flow after sensing ends.

Repair Steps:

1. Weak flushing: Refer to the "clean water inlet filter screen" step for manual models to unclog the valve body water inlet channel and check if the water inlet pipe is kinked (ensure smooth water flow);

2. Continuous leakage:

• If the solenoid valve fails to close tightly: Disassemble the solenoid valve and replace the internal "sealing diaphragm" (thin rubber sheet that cannot seal water flow after aging);

• If leaking from the "valve body and urinal connection": Check the "silicone sealing ring" at the connection. Replace if damaged, and moderately tighten the connecting nut with a wrench (avoid over-tightening to prevent gasket damage).

III. Universal Pitfall Avoidance Guide: 3 Key Notes

IV. When to Replace the Entire Flush Valve?

Do not repair; directly replace the valve for higher efficiency if:

• The valve body has obvious cracks (leakage cannot be repaired with seals);

• The sensor module is faulty (the cost of replacing the module is close to that of a new valve);

• It is an old model (accessories are discontinued, and compatible seals or solenoid valves cannot be purchased).

Note: When replacing with a new valve, pay attention to the "water inlet size" (common is 1/2-inch interface, matching the angle stop valve) and "installation height" (the sensor panel should be 1.2-1.5 meters above the ground, in line with the human body sensing range). Install according to the instructions.

If you need detailed repair steps for a specific brand (e.g., TOTO, Kohler) or fault type (e.g., solenoid valve burnout), provide specific information, and I will further supplement the operation details!