To determine whether the valve core of a faucet needs to be replaced, one can start from three aspects: abnormal performance during daily use, structural inspection, and simple tests. The following are the specific methods and judgment basis:
1. Observe any abnormal symptoms during use
The faucet is dripping or not closed tightly
Performance: After turning off the faucet, water continues to drip from the outlet (more than 1 drop per minute), or the water flow does not stop completely after the handle is fully tightened.
Reason: The valve core sealing parts (such as ceramic plates, rubber rings) age, wear or are contaminated with impurities, resulting in poor closure.
Judgment: If the dripping and leakage problem does not improve after wiping the water outlet and cleaning the bubble generator, it is highly likely that the valve core is faulty.
Abnormal rotation of the handle
Symptoms: When opening or closing the handle, there is a feeling of lag, a significant increase in resistance, or abnormal noises (such as a “click” sound) occur during rotation. Some faucet handles are loose or even fall off.
Cause: The spring inside the valve core is rusty, the ceramic plate is worn out and misaligned, or the fixing parts are loose.
Judgment: If the handle does not rotate smoothly and is accompanied by abnormal noises, the valve core needs to be disassembled for inspection (Note: Some faucet handles require special tools for disassembly).
The adjustment of hot and cold water is malfunctioning
Symptoms: The double-hole faucet (with cold and hot water separated) or the constant-temperature faucet cannot mix the water temperature normally, such as only being able to produce cold or hot water, or the water temperature suddenly becomes too hot or too cold when adjusted.
Cause: The thermosensitive element inside the thermostatic valve core has failed, or the seal of the water distribution valve core is damaged, resulting in the cross-flow of cold and hot water.
Judgment: If the water temperature remains unchanged when adjusting the handle, or if both the cold and hot water pipes are discharging water simultaneously (in an abnormal mixed state), it is necessary to focus on inspecting the valve core.
Second, disassemble the faucet to inspect the appearance of the valve core
Preparations: Close the main water valve, open the faucet to drain the remaining water in the pipeline, and prepare tools such as wrenches and screwdrivers.
Remove the handle and decorative cover
Most faucet handles have fixing screws at the bottom (which may be hidden under the decorative cap). Unscrew them with a screwdriver and remove the handle to expose the main body of the valve core.
The valve core of a single-hole faucet is usually circular, while a double-hole faucet may have two independent valve cores (one for cold water and one for hot water).
Observe the state of the valve core
Ceramic valve core (commonly found in mainstream faucets) :
Normal condition: The surfaces of the upper and lower ceramic plates are smooth, free of scratches or cracks, and the edge sealing rings are not deformed or hardened.
Replacement required: The ceramic plate has obvious wear grooves or cracks, or the sealing ring is sticky or broken (as shown in Figure ①).
Rubber valve core (commonly seen in old-fashioned faucets) :
Normal condition: The rubber pad has sufficient elasticity, and there are no bubbles or damages on the surface.
To be replaced: The rubber pad is swollen, cracked, or covered with a large amount of scale that cannot be cleaned (as shown in Figure ②).
Stainless steel ball valve core
Normal state: The surface of the sphere is bright and shiny, and it rotates smoothly without any jamming.
Replacement required: rusted ball, aged sealing ring, or internal spring breakage and loss of elasticity.
Test the sealing performance of the valve core
After removing the valve core, pour a small amount of clear water into the water inlet of the faucet and observe whether there is water seepage at the bottom.
If there is no water seepage, it indicates that components other than the valve core (such as O-rings, valve bodies) may be leaking water.
If there is direct leakage, the valve core seal fails and needs to be replaced.
Iii. Auxiliary judgment based on the effluent status
The water flow rate decreases or becomes unstable
Performance: Under the same water pressure, the water output is significantly weaker or sometimes larger and sometimes smaller. It is necessary to rule out problems such as pipe blockage or impurities in the foaming device.
The reason is that the internal channels of the valve core are blocked by scale and impurities, or the ceramic plate is worn, resulting in a reduction in the water passage area.
Judgment: After disassembling the valve core and observing the internal flow channel, if there is a large accumulation of scale that is difficult to remove, a new valve core needs to be replaced.
The water output of cold and hot water varies greatly
Performance: When a double-hole faucet is used for cold or hot water alone, the water output on one side is significantly less than that on the other.
Cause: The filter screen at the water inlet corresponding to the valve core is clogged, or the opening degree of the valve core is insufficient (such as the ceramic plate being stuck).
Judgment: After disassembly, check whether the filter screen at the water inlet end of the valve core (if any) is clogged with sand or rust, and at the same time test whether the valve core opens and closes smoothly.
Iv. Targeted Judgment of Different Types of Leading Enterprises
Single-handle hybrid faucet
Most faults are concentrated in the thermostatic valve core or the water distribution valve core. If the water flow suddenly stops or cross-flows when adjusting the temperature, first check whether the piston inside the valve core is stuck.
Pull the faucet in the kitchen
If the water output from the hose is intermittent when pulled out, in addition to checking whether the hose is folded, it is necessary to inspect whether the sealing ring at the connection between the valve core and the hose is worn (as frequent pulling and pulling can easily cause the sealing parts to loosen).
Shower faucet
If the showerhead and the top spray fail to switch the water flow, it might be due to a malfunction of the switching valve core (internal paddle or spring failure), and the main body of the faucet needs to be disassembled for inspection.
V. Suggestions for the Timing of Replacing the valve Core
Immediate replacement: In case of continuous dripping, handle breakage, or complete loss of control over hot and cold water (such as inability to turn off the hot water), it is necessary to handle it as soon as possible to avoid the risk of furniture damage or scalding caused by water leakage.
Preventive replacement: For faucets that have been in use for more than five years without maintenance, even if there are no obvious faults, it is recommended to regularly inspect the valve core (especially the rubber material) to prevent sudden problems caused by aging.
Pay attention to compatibility: Before replacement, confirm the valve core model (such as size, interface type), common specifications include DN15, DN20, etc., or directly bring the old valve core to the building materials market for matching to avoid installation failure due to model mismatch.
Through the above methods, the problem of the valve core can be quickly located and a decision can be made on whether to replace it. If you are not familiar with the disassembly steps during the operation or if it involves installing faucets in the wall, it is recommended to contact a professional plumber for handling to avoid self-disassembly and causing more damage.
Post time: May-03-2025
