Page 259 - Intro Predictive Maintenance

250 An Introduction to Predictive Maintenance

Table 10–16 Common Failure Modes of Steam Traps

THE PROBLEM

Trap Will Not Discharge Will Not Shut-off Continuously Blows Steam Capacity Suddenly Falls Off Condensate Will Not Drain Not Enough Steam Heat Traps Freeze in Winter Back Flow in Return Line

THE CAUSES
Back-Pressure Too High
Boiler Foaming or Priming
Boiler Gauge Reads Low
Bypass Open or Leaking
Condensate Load Greater Than Design
Condensate Short-Circuits
Defective Thermostatic Elements
Dirt or Scale in Trap
Discharge Line Has Long Horizontal Runs
Flashing in Return Main
High-Pressure Traps Discharge into Low-Pressure Return
Incorrect Fittings or Connectors
Internal Parts of Trap Broken or Damaged
Internal Parts of Trap Plugged
Kettles or Other Units Increasing Condensate Load
Leaky Steam Coils
No Cooling Leg Ahead of Thermostatic Trap
Open By-Pass or Vent in Return Line
Pressure Regulator Out of Order
Process Load Greater Than Design
Plugged Return Lines
Plugged Strainer, Valve, or Fitting Ahead of Trap
Scored or Out-of-Round Valve Seat in Trap
Steam Pressure Too High
System Is Air-Bound
Trap and Piping Not Insulated
Trap Below Return Main
Trap Blowing Steam into Return
Trap Inlet Pressure Too Low
Trap Too Small for Load
Source: Integrated Systems, Inc.