What do Spirax Sarco steam traps do?
Spirax Sarco steam traps discharge condensate, air and non-condensable gases from steam systems while helping reduce live steam loss. The range covers ball float, thermodynamic, thermostatic, inverted bucket and bimetallic traps for steam mains, heat exchangers, tracing, clean steam and condensate recovery duties.
Main steam trap types
The right trap type depends on condensate load, pressure differential, air venting, back pressure, installation position and maintenance strategy.
| Type | Key feature | Typical applications | Representative models |
|---|---|---|---|
| Ball float steam traps | Continuous discharge, modulating with condensate load. | Heat exchangers and process equipment. | FT14 ball float steam trap, FT43 ball float steam trap, FT44 / FT46 / FT47 / FTGS14 / FTS14 / UFT32 ball float steam trap |
| Thermodynamic steam traps | Compact intermittent operation for mains and exposed pipework. | Steam mains, distribution and tracing. | TD32F, TD42, TD42L, TD52, TD62, TD120M thermodynamic steam trap |
| Thermostatic / balanced pressure traps | Temperature-operated discharge, often with controlled subcooling. | Tracing, mains drainage and process drains. | BPC32 / BPC32Y balanced pressure steam trap, BPC32YCV balanced pressure steam trap, MST21 balanced pressure steam trap, BPT13 / BTM7 / UBP32 thermostatic steam trap |
| Inverted bucket traps | Mechanical intermittent discharge for stable loads. | Larger equipment and selected main drainage duties. | HM34, S/SF, SIB, UIB |
| Trap stations and monitored traps | Integrated isolation, testing, monitoring or service functions. | Plants needing easier inspection and maintenance. | STS17.2, IFT14, ITD32, IBPC32 |
Choose by application
Steam traps should be selected around the duty, not only connection size. Steam mains, heat exchangers, tracing lines and clean steam systems have different drainage, air venting, space and service requirements.
Model and resource entry points
Use the model table to move from common Spirax Sarco steam trap families to the closest product category or product page. Product pages are the right place to confirm dimensions, pressure rating, installation instructions and PDF resources.
| Model / series | Type | Application direction |
|---|---|---|
| FT14 / FT14HC / FT14X | Ball float | Small connection sizes, continuous drainage and integral air vent options. |
| FT43 / FT44 / FT46 / FT47 | Ball float | Flanged connections, larger sizes and higher condensate loads. |
| TD32F / TD42 / TD52 / TD62 | Thermodynamic | Steam mains, tracing and process drainage with compact construction. |
| BPC32 / BPC32Y / BPC32YCV | Balanced pressure thermostatic | Tracing and duties where controlled condensate cooling is acceptable. |
Data to confirm before selection
- Operating pressure, differential pressure and back pressure
- Running load, start-up load and load variation
- Air venting and start-up requirements
- Discharge temperature requirement
- Connection, material, orientation and service space
- Waterhammer, vibration, outdoor temperature, corrosion or dirt risk
- Need for strainer, check valve, blowdown, monitoring or trap station
Failure, monitoring and lifecycle management
A failed-open trap can waste steam and increase emissions. A failed-closed or blocked trap can cause waterlogging, waterhammer and unstable heat transfer. Critical plants should keep a trap register, inspect trap condition and consider continuous monitoring where access or failure cost is significant.
Installation and maintenance points
Install traps close to the drain point and below the equipment outlet where possible. Consider upstream strainers, downstream check valves, isolation, testing and blowdown arrangements. Avoid draining multiple process units through one trap unless the system has been designed for that arrangement.
Detailed selection, installation and maintenance guide
Application-based selection
Select the trap around the drainage duty, available pressure differential, air venting requirement and maintenance conditions.
| Application-based selection | Data to confirm before selection |
|---|---|
| Steam mains | Drain low points promptly and confirm air venting, pressure differential and exposure to weather. |
| Heat exchangers | Continuous drainage and stable heat transfer are important; include start-up load in the sizing check. |
| Steam tracing | Confirm permitted condensate cooling, corrosion resistance, space and start-up air removal. |
| Clean steam | Confirm material, hygienic connection, self-drainage and validation requirements. |
| Condensate recovery | Check downstream back pressure, return risk and any need for check valves or pumping. |
Key models and resources
Use these model entry points to open product details, installation guidance and technical documentation.
| Model / series | Type | Product and installation information |
|---|---|---|
| FT14 ball float steam trap | ball float steam trap | Product and installation information |
| FT43 ball float steam trap | ball float steam trap | Product and installation information |
| FT44 / FT46 / FT47 / FTGS14 / FTS14 / UFT32 ball float steam trap | ball float steam trap | Product and installation information |
| TD32F / TD42 / TD42L / TD52 / TD62 / TD120M thermodynamic steam trap | thermodynamic steam trap | Product and installation information |
| BPC32 / BPC32Y balanced pressure steam trap | balanced pressure steam trap | Product and installation information |
| BPC32YCV balanced pressure steam trap | balanced pressure steam trap | Product and installation information |
| MST21 balanced pressure steam trap | balanced pressure steam trap | Product and installation information |
| BTM7 / BTS7 clean-steam thermostatic trap | clean-steam thermostatic trap | Product and installation information |
Data to confirm before selection
Use the actual pressure differential between trap inlet and outlet. Check both normal operation and cold start-up.
- Operating pressure, differential pressure and return-line back pressure
- Running load, start-up load and load variation
- Air venting, steam locking and discharge-temperature requirements
- Connection, materials, orientation and access for maintenance
- Dirt, waterhammer, vibration, corrosion and outdoor exposure
Installation and maintenance checks
| Check | Practical requirement |
|---|---|
| Position | Install close to the drain point and below the equipment outlet where practical. |
| Orientation | Follow the flow arrow and the installation direction for the selected model. |
| Cleanliness | Clean pipework before start-up and maintain strainers where fitted or required. |
| Isolation | Provide suitable isolation and space for safe service and replacement. |
| Backflow | Assess check valves and the condensate-recovery arrangement where reverse flow is possible. |
Condition monitoring and lifecycle management
A trap failing open can waste live steam; a blocked or failed-closed trap can cause waterlogging, waterhammer and unstable heat transfer. Keep a trap register, inspect critical points and investigate the system conditions as well as the trap itself.
Frequently asked questions
How do I choose between a ball float and thermodynamic trap?
Ball float traps are often compared for continuous drainage at heat-transfer equipment, while thermodynamic traps are widely used on mains and tracing. Confirm the duty, differential pressure, air venting and maintenance conditions.
Why is pipe size not enough for selection?
Pipe size does not establish condensate load, available pressure differential or start-up demand. These values must be checked for the actual duty.
Where can I find FT14, FT43, TD52 and MST21 installation information?
Use the model links on this page to reach the published product details, installation instructions and technical documentation.