Addressing Leaking Stems on Ball Valves

Leaking stems on ball valves can be a common issue, particularly in hydronic systems with treated water. Typically also in commercial hydronic systems. If you’re noticing multiple stem leaks on a job site, there’s a good chance that water chemistry is the culprit. Understanding the root cause and selecting the right solution can prevent ongoing failures and improve system longevity.

🔎 Common Causes of Stem Leaks in Ball Valves

1. Chemical Breakdown of O-Ring Seals

   • Many ball valves use EPDM (ethylene propylene diene monomer) O-rings for stem sealing.

   • EPDM is highly resistant to heat and general wear but is susceptible to chemical degradation from certain water treatments.

2. High Glycol Concentration

   • Glycol-based antifreeze is commonly used in HVAC and hydronic systems for freeze protection.

   • Over time, excessive glycol levels can degrade EPDM O-rings, leading to leaks.

   • Improperly mixed or overly concentrated chemical treatments accelerate this process.

3. General Water Chemistry Issues

   • Corrosive or improperly balanced water chemistry can attack valve components.

   • High levels of chlorides, pH imbalance, or excessive additives contribute to premature valve failures.

💡 Solutions to Prevent Ball Valve Stem Leaks

✔️ Reevaluate Chemical Concentration

• If leaks are widespread, it may be time to reset and rebalance the system’s chemical treatment.

• Consult water treatment guidelines to ensure proper glycol-to-water ratios.

✔️ Consider Alternative Valve Designs

• Globe Valves with Teflon Packing offer a metal-to-metal seal instead of relying on an O-ring.

• These are more resistant to chemical breakdown and may be a better long-term solution in aggressive water conditions.

✔️ Regular Water Testing & Treatment Adjustments

• Periodic water testing can help detect imbalances before they cause system damage.

• Adjustments to water chemistry should be made proactively, rather than waiting for leaks to develop.

🔧 Need Chemical Treatment Support?

If you suspect water chemistry is affecting your system’s valves, contact us for expert guidance on chemical treatment solutions. Proper maintenance and chemical balance can extend the lifespan of your valves and prevent costly failures.