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Flame Tech Flow Meter Troubleshooting: Fixing Gas Leakage and Ball Float Inaccuracies
Quick Answer
Most gas leakage on Flame Tech flow meters starts at threaded joints, O-ring seats, or the inlet fitting. Check those points with soapy water before replacing the meter. Ball float inaccuracies usually come from back pressure changes, dirt on the float, or installation angle, not from the metal tube itself.
Gas Leakage Checks for Flame Tech Flow Meters
Gas leaks rarely mean the meter body is cracked. In practice we see leaks at the process connection, the inlet fitting, the O-ring, or the valve packing. A customer in the Philippines ran biogas through a DN25 unit at 1.5 bar and found a small leak at the inlet thread. The thread had been wrapped with PTFE tape but the tape was applied in the wrong direction. Re-taping the thread solved it in 10 minutes.
Start with a visual inspection. Look for moisture, discoloration, or fine bubbles after applying soapy water. For gas service use a leak detection spray that matches the gas type. Do not use soap on oxygen service lines. Wait at least 60 seconds after spraying. Small leaks on stainless steel fittings may produce micro bubbles that appear slowly.
Then shut off the inlet valve and isolate the meter. Observe the pressure gauge for 5 minutes. A pressure drop above 0.1 bar often points to a seat leak or a fitting leak. Tighten the leaking fitting while the line is depressurised. Do not over torque. For a DN15 or DN25 Flame Tech flow meter, hand tight plus a quarter turn is often enough. If the leak continues, replace the O-ring. Use Viton or PTFE seals for aggressive gases. Use Buna-N only for clean air.
Ball Float Inaccuracy Causes and Fixes
Most ball float reading errors come from the process conditions, not the tube. Back pressure is the biggest cause. A variable area flow meter assumes a stable pressure at the outlet. If the downstream valve closes partially or the filter blocks, the ball may rise higher than the actual flow. A water treatment plant in Malaysia had a Flame Tech meter reading 20 percent high because a dosing pump downstream created pressure pulses. Adding a small back pressure valve fixed the reading.
Dirt and scale on the ball or tube wall create drag. The float may stick or jump. Remove the meter from the line and clean the tapered tube with mild detergent or a solvent that is compatible with the wetted parts. Do not use abrasive pads on the tube. A scratched tube changes the internal diameter and the reading. Rinse with clean water and dry with compressed air before reinstallation.
Installation angle also matters. The meter must be vertical. A tilt of more than 5 degrees creates friction between the ball and the tube wall. Check the mounting with a spirit level. If the line vibrates, install a support bracket or move the meter to a steady section of pipe.
Gas density changes also shift the ball position. If the gas temperature or pressure changes after calibration, the reading will drift. For example a CNG flow measurement at 30 bar and 20 °C will not match the scale at 5 bar and 40 °C. Record your actual gas pressure and temperature before ordering or recalibrating. Silver Instruments can help with a corrected scale if you send the gas ty
Step by Step Field Test for Flame Tech Flow Meters
First isolate the meter and release pressure. Second remove the inlet fitting and inspect the seat. Third clean the ball and tube with a lint free cloth. Fourth reinstall the fitting with fresh sealant. Fifth pressurise the line to the normal operating pressure. Sixth apply leak detection spray and wait for one minute. Seventh open the downstream valve and compare the ball position against a reference flow meter or a calibrated mass flow controller. This sequence works for DN15, DN25, and DN40 metal tube units used on air, nitrogen, biogas, or CNG.
If the ball still reads high or low after cleaning and sealing, send the meter for a bench calibration. Do not adjust the indicator screws on the panel unless you have a reference standard. We have seen many units with tampered screws that made the reading worse.
When to Replace Instead of Repair
Replace the meter if the tapered tube is cracked, the float is bent, or the O-ring groove is corroded. A cracked tube on a gas line can leak even after fitting replacement. A bent float causes repeatability errors above 5 percent of full scale. For high pressure gas above 10 bar, a new meter body is usually safer than repairing an old unit. Silver Automation Instruments supplies Flame Tech flow meters from stock for common gas ranges. We also provide repair kits with O-rings, floats, and inlet fittings for DN15, DN25, DN40, and DN50 bodies.
Contact Silver Automation Instruments
If you need a replacement Flame Tech flow meter or a repair kit, send us your gas type, pressure in bar, temperature in °C, pipe size DN, and flow range. Our engineers reply within one working day. Tel: +86-25-68650347. Whatsapp: +86-25-52155837. WeChat: +86 15365082610. We serve industrial users and distributors in Southeast Asia, Oceania, Latin America, the Middle East, and Africa.
FAQ
Why does my Flame Tech flow meter leak at the inlet after installation?
The inlet thread may be cross threaded or the O-ring may be dry. Depressurise the line, check the thread, replace the O-ring, and apply the correct sealant for your gas type.
What causes the float to stick at low flow?
Dirt, oil residue, or a tilted installation are the usual causes. Clean the tube and ball, then mount the meter vertically with a support bracket if needed.
Can I use a Flame Tech flow meter for biogas with moisture?
Moisture affects the float reading. Use a stainless steel body with Viton seals and install a moisture trap upstream. Send us your gas analysis for a proper material check.
How do I know if the scale is correct for my gas?
The standard scale is only valid for a defined gas, pressure, and temperature. If your actual conditions differ, the reading will be off. Silver Instruments can make a corrected scale if you provide the operating data.
When should I replace the ball float instead of cleaning it?
Replace the float if it is bent, pitted, or heavily coated after cleaning. A damaged float will not give repeatable readings within the accuracy class of the meter.
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