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Steam Lock Release - When a trap is installed above the discharge of the process, the trap can be locked due to trapped steam in the piping. To help eliminate this requires an optional steam lock release mechanism.

Operating Condition
Condensate Load  
WFT Float & Thermostatic

WFT Float & Thermostatic Steam Trap

WFT-Series Float and Thermostatic Steam Traps have Cast Iron Bodies ••• Parallel Port Connections ••• 250 psig Operating Pressures ••• Stainless Steel Internals. Typically used on steam process applications such as unit heaters, pressing machines, heat exchangers, steam coils. They contain a welded stainless steel thermostatic air vent for rapid air removal on system start-up and all stainless steel internals.

Size Connection PMO (PSIG) Max Capacity
3/4" - 2" NPT 250 11,000 lbs/hr

ModelSizeTypeOptionsMax PMO (psig)Max Capacity @ Max PMO (lb/hr)
WFT-015-15-N1 1/4"NPT15
WFT-015-16-N1 1/2"NPT15
WFT-030-15-N1 1/4"NPT30
WFT-030-16-N1 1/2"NPT30
WFT-075-15-N1 1/4"NPT75
WFT-075-16-N1 1/2"NPT75
WFT-125-15-N1 1/4"NPT125
WFT-125-16-N1 1/2"NPT125
WFT-175-15-N1 1/4"NPT175
WFT-175-16-N1 1/2"NPT175
WFT-250-15-N1 1/4"NPT250
WFT-250-16-N1 1/2"NPT250
Product Overview
PROCESS, DRIP:  WFT Series with parallel port connections were specifically designed for removing condensate and air from HVAC and industrial process applications such as unit heaters, pressing machines, heat exchangers and coils. They contain a high-quality welded stainless steel thermostatic air vent and stainless steel mechanism. The WFT Series are fully repairable while the trap remains in-line and are available in 3/4” thru 2" NPT connections. 

For drip applications, such as draining steam mains and steam supply lines, use model 3/4” WFT-125 (WFT-125-13-N).
• All stainless steel internals with hardened seat and wear parts 
• In-line repairability is simplified by having all internals attached to the cover 
• Welded stainless steel thermostatic air vent resists shock from waterhammer. Live orifice air vent is available for superheated applications 
• Excellent air handling capability allows air to be discharged rapidly so steam can enter the system quickly during start-up 
• F&T traps discharge condensate immediately as it is formed (no condensate will back up into the system)
How It Works
Float and thermostatic traps contain a float-operated valve and seat mechanism with a separate thermostatic element which work together to remove both condensate and air from the steam system. The float, which is attached to a valve, rises and opens the valve when condensate enters the trap, allowing the condensate to discharge. Air is discharged through the thermostatic air vent to the outlet side of the trap. Steam entering the trap causes the thermostatic element to expand, closing the air vent and trapping the steam.
Selection / Sizing / Capacities
The PMO (maximum operating pressure) rating of model selected must meet or exceed the maximum steam pressure or the trap may not open. For example; the WFT-125 has a PMO of 125 psi. Condensate capacity (lbs/hr) of the trap is based on the differential pressure across the trap. For drip applications, a 3/4" WFT size is generally sufficient to exceed warm-up loads with a 2X safety factor. The condensate loads (lbs/hr) for process applications are normally calculated at the maximum steam pressure; then an appropriate safety margin is applied in order to select a trap with sufficient capacity when operating at lower steam pressures. Reference full explanation of Safety Load Factors in Steam Trap Introduction section.

When a temperature control valve regulates the flow of steam to the process equipment (Heat Exchanger) being drained of condensate, it is recommended to select a trap with a PMO that exceeds the inlet steam pressure to the temperature control valve. This assures that under all operating conditions, the steam pressure will not exceed the PMO of the trap.

For Example:
Process application has a maximum steam inlet pressure of 100 psi, a maximum condensate load of 2,500 lbs/hr and is discharging to a condensate return line with a possible back pressure of 25 PSIG. ΔP = 100-25 = 75 PSI

To select trap:
If the Safety Load Factor is chosen to be 2X max capacity at max differential pressure, then Trap should be selected based on 5,000 lbs/hr (2,500 x 2 = 5,000) at 75 PSI differential pressure with a PMO in excess of 100 PSIG

WFT-125-17-N, PMO=125 PSIG, 2” NPT with a condensate capacity of 7,460 lbs/hr at 75 PSI differential pressure.

Dimension and Weights
• Live orifice air vent for superheated steam applications.
• NPT Connection for freeze protection
Installation and Maintenance
The trap must be installed upright and level for the float mechanism to operate properly. All internal components can be replaced with the trap connected in-line. Repair kits include thermostatic air vent, float, valve seat and disc, and gaskets. The standard thermostatic air vent can be damaged by superheat; therefore, in applications with superheated steam, the thermostatic air vent should be replaced with a special “live orifice” air vent.

Demonstration of Parallel piping connections: