The troubleshooting guides below can serve to help you independently assess issues, zero down on the root cause and resolve issues pertaining to steam trap failures with minimal external assistance. While we have attempted to make it as detailed as possible, there could be site specific design related aspects which could also lead to failure. If the above guide does not resolve the issue contact your local Forbes Marshall engineer to assist you with troubleshooting.
Illustration: Components of a thermodynamic steam traps
| Failure Mode | Symptom | Possible Causes and Recommended Actions |
|---|
| Not discharging condensate at all | Trap is cold and not discharging any condensate | - Inlet drip leg is choked or strainer screen 4 is clogged with dirt / debris.
Flush the drip leg / clean the trap strainer screen. If the strainer screen 4 is rusted, replace it with a new one. - Differential pressure is low (Verify the inlet and outlet pressure of the steam trap. The minimum differential pressure required is 0.25 barg).
- Air binding of the disc.
First, unscrew the cap 2 and screw it back on tightly (to suitable torque). - Flash steam locked (trapped) inside the steam trap.
Pour water on cap 2 of the steam trap to release flash steam locked (trapped) inside the steam trap so that it discharges condensate.
|
| Trap is hot and not discharging any condensate |
| Steam leakage | Steam is leaking continuously from the trap | - The bypass valve is open / leaking.
- Ensure that the bypass valve is fully closed. Replace the valve if it is found to be leaking Trap is not installed correctly.
Rectify the installation i.e. the cap 2 should be on top and the condensate should flow in the direction of the arrow provided on the steam trap body. - Dirt, debris, oil film, etc is present on the disc or seat preventing a proper sealing between the disc and seat.
Clean both the disc and body seat. If required lap the disc and seat individually.
Note: The total amount of metal from body seal face removed should not exceed 0.25mm. - Disc is stuck to the cap.
Give a light tap to the top of the cap to see if it resolves the problem. If the step i.e. the inner surface of the cap is worn out, replace the trap. - The back pressure exceeds the allowable value i.e. the outlet pressure of the trap should not exceed 80% of the inlet pressure.
- Scratch on disc or seat.
If the depth of the scratch is less the problem can be resolved by lapping the disc / seat, else the disc will require to be replaced.
Note: The total amount of metal from body seal face removed should not exceed 0.25mm.
|
| Rapid Cycling | Continuous chattering of the disc | - Disc or seat is worn.
- Replace a worn disk with a new one. If the seat is slightly worn, lapping can address the issue. However, in case of excessive wear, replace the seat or the steam trap.
Note: It is important to promptly maintain a steam trap that is rapid cycling. Timely maintenance can prevent excessive wear of the disc / seat. |
