There are many factors that affect steam generating system in the energy industry, and multiple pros and cons in selecting a right steam trap for your application, the following are advantages vs. disadvantages of each type of steam trap to consider when selecting one for your project.


AdvantagesDisadvantages
Disc Steam Traps

• Failure mode. gradually, predictably open over time.

• Simple construction.

• Small size and light weight.

• Can be mounted in any position.

• Rugged. withstands water hammer.

• Self draining, not damaged by freezing.

• Function not impaired by superheat.

• Versatile, suitable for wide pressure range.

• Condensate discharge temperature closely follows the saturation curve.

• Performance is easily checked in field.

• Marginal air handling capability.

• Excessive backpressure in return systems can prevent trap from closing.

• Life is reduced significantly as pressures move above 300 psi.

• High discharge noise level.

• Dirt particles can increase cycle rate causing wear.

Piston Steam Traps

• Suitable for high pressure

• Can be mounted in any position.

• Good response to changing condensate load conditions.

• Rugged, withstands water hammer.

• Self-draining, not damaged by freezing.

• Function not impaired by superheat.

• Good air handling capability.

• Primary failure mode-open.

• Small size and light weight.

• Excessive backpressure in return systems can prevent trap from closing.

• Condensate discharge temperature follows the saturation curve over a limited range.

• Difficult to field check because of continuous control flow discharge.

Lever Steam Traps

• Suitable for high pressure applications.

• Good response to changing condensate load conditions.

• Rugged, withstands water hammer. 

• Not damaged by freezing.

• Function not impaired by superheat. 

• Good air handling capability.

• Small, compact, easy to install and service.

• Excessive back pressure in return systems can prevent trap from closing.

• Difficult to field check due to continuous control flow discharge.

• Can only be mounted in one position.

Closed Float Steam Traps

• Unaffected by sudden or wide pressure changes.

• Responds very quickly to condensate load changes.

• Continuous discharge.

• Condensate discharge temperature closely follows the saturation curve.

• Function is not impaired by high back pressures.

• Energy efficient.

• Simple construction.

• Relatively large and heavy.

• Float easily damaged by water hammer.

• Does not withstand freezing.

• Can be mounted only in one position.

• Suitable only for relatively low pressures.

• Requires auxiliary air vent which is an additional source of failure.

• Primary failure mode is closed.

• Not self draining.

Inverted Bucket Steam Traps

• Simple construction.

• Rugged.

• Condensate discharge temperature closely follows the saturation curve.

• Reliable.

• Marginal air handling during start-up.

• Not self draining; subject to freeze ups.

• Not suitable when superheat is present.

• Can lose prime. and is not self-priming.

• Can be mounted only in a single position.

• Failure mode is unpredictable (open or closed).

Open Bucket Steam Traps

• Simple construction.

• Reliable.

• Condensate discharge temperature closely follows the saturation curve.

• Function not impaired by high back pressure.

• Fast response to changing condensate loads.

• Not self draining; subject to freeze ups.

• Not suitable when superheat is present.

• Can lose prime, not self-priming.

• Can be mounted only in a single position.

• Requires auxiliary air vent which is an additional source of failure.

• Suitable only for relatively low pressures.

• Relatively large and heavy.

Bimetallic Steam Trap

• Rugged.

• Energy efficient.

• Self draining.

• Resistant to freeze damage.

• Withstands water hammer.

• Capable of discharge temperature adjustment.

• Can be mounted in several positions.

• Primary failure mode-open.

• Dirt particles can prevent tight valve closing.

• Condensate discharge temperatures do not follow the saturation curve closely.

• Difficult to field check when operating in a throttling mode.

• Condensate discharge temperature is made lower as backpressure increases.

• Relatively slow response to changing condensate loads.

• Bimetallic elements are relatively susceptible to corrosion.

Bellows Steam Traps

• Excellent air handling capability.

• Energy efficient.

• Self draining.

• Various condensate discharge temperatures available depending on bellows design.

• Condensate discharge temperature follows the saturation curve.

• Can be mounted in several positions.

• Simple construction.

• Small size and weight.

• Bellows elements tend to be failure prone, especially when subjected to water hammer.

• Difficult to field check when operating in a throttling mode.

• Generally not suited for high pressure applications.

• Limited superheat capability.

• Short stroke diaphragm design susceptible to dirt initiated failures.

Liquid or Solid Expansion Steam Traps (Wax Capsule Steam Trap)

• Rugged.

• Good air handling capability.

• Resistant to freeze damage.

• Withstands water hammer.

• Can be mounted in any position.

• Self draining.

• Primary failure mode is open.

• Dirt particles can prevent tight close.

• Requires substantial sub-cooling.

• Difficult to field check.

• Slow response to changing condensate loads.

• Actuator damaged by exposure to high temperature.

Orifice Steam Traps

• No moving parts.

• Suitable for high pressure application.

• Rugged, withstands water hammer.

• Not damaged by freezing.

• Function not impaired by superheat.

• Can be mounted in any position.

• Orifice size must be carefully selected for each installation.

• Can not respond to varying condensate loads.

• Inefficient if oversized.

• Dirt particles readily impair performance.

• Difficult to field check because of continuous discharge.

• In the absence of condensate, the trap passes live steam.