The Spirax Sarco FT43 series cast iron ball float steam trap is a flanged condensate drainage device rated for PN16 pressure, available in nominal sizes from DN25 to DN100. The series features a cast iron body and stainless steel internals, with an integrated thermostatic automatic air vent, and optional steam lock release device (FT43-C) or vertical installation configuration (FT43V). It is suitable for steam heat exchangers, low points in steam mains, and heating equipment prone to steam locking, providing continuous condensate discharge in response to varying condensate loads.
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Spirax Sarco FT43 Series Cast Iron Ball Float Steam Traps (DN25-DN100)
Cast iron ball float steam traps for continuous condensate discharge from steam equipment and main pipelines, with an optional steam lock release device.
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Models
The FT43 series consists of PN16 cast iron float steam traps equipped with an integral thermostatic automatic air vent. The main differences are the installation configuration and steam-lock handling function. Select FT43 when standard horizontal installation is available on site and no special steam-lock handling is required. Select the horizontally installed FT43-C when a manual steam-lock-breaking device is required. Select FT43V when the piping requires vertical downward flow. When selecting a model, also verify the nominal size, actual pressure and temperature, maximum differential pressure, and flange standard.
FT43Standard cast iron float steam trap
FT43 is the standard horizontally installed float steam trap in the FT43 series. It features a cast iron body and cover, stainless steel internals, and an integral thermostatic automatic air vent. It uses flanged connections and is available in DN25, DN40, DN50, DN80, and DN100 sizes, with a nominal pressure rating of PN16. Its maximum allowable pressure is 16 bar g @ 120°C, and its maximum allowable temperature is 220°C @ 12.1 bar g. This model does not include a manual steam-lock-breaking device. It must be installed horizontally according to the flow direction indicated on the valve body.
FT43-CHorizontally installed cast iron float steam trap with steam-lock-breaking device
FT43-C is a horizontally installed float steam trap based on FT43 with an added manual steam-lock-breaking device, SLR, while retaining the integral thermostatic automatic air vent. It features a cast iron body and stainless steel internals, has a nominal pressure rating of PN16, and is available in DN25, DN40, DN50, DN80, and DN100 sizes. It is suitable for horizontal installation applications requiring steam-lock handling.
FT43VVertically installed cast iron float steam trap
FT43V is the vertically installed float steam trap in the FT43 series, with downward flow. It features a cast iron body, stainless steel internals, and an integral thermostatic automatic air vent. This model is suitable for piping systems that require vertical installation and must not be used in the standard horizontal installation configuration of FT43.
Specifications
- Nominal Pressure
- PN16
- Nominal Size
- DN25, DN40, DN50, DN80, DN100
- Connection Type
- Flanged connection
- Flange Standard
- EN 1092 PN16 (flange facing complies with EN 26554 Series 1); JIS/KS 10 and ANSI B 16.5 Class 125 available
- Maximum Allowable Pressure
- 16 bar g @ 120°C
- Maximum Allowable Temperature
- 220°C @ 12.1 bar g
- Maximum Operating Pressure
- 13 bar g @ 195°C (with saturated steam)
- Minimum Operating Temperature
- 0°C
- Cold Hydraulic Test Pressure
- 24 bar g (must not exceed the maximum differential pressure after installation of internal components)
- Maximum Differential Pressure Options
- FT43-4.5: 4.5 bar, FT43-10: 10 bar, FT43-14: 13 bar
- Air Venting Device
- Built-in thermodynamic automatic air vent valve assembly
- Steam Lock Release Function
- Optional manual steam lock release device (SLR), model FT43-C
- Superheated Steam Service Range
- 150°C superheat @ 0 bar g, 50°C @ 32 bar g (BP99/32 liquid-filled capsule)
- Body Material
- Cast iron (DIN 1691 GG20 / EN-JL 1040)
- Cover Material
- Cast iron (EN JL 1040)
- Internal Components Material
- Stainless steel (main valve, float mechanism, air vent valve, etc.)
- Gasket Material
- Reinforced sheet graphite
- Installation Requirements
- Install horizontally in the direction of flow with the float arm horizontal; vertical installation configuration available (FT43V)
- Certifications
- European Pressure Equipment Directive 97/23/EC (CE); EN 10204 2.2 certificate (optional)
- Weight
- Approx. 8.3 kg (DN25), approx. 21.5 kg (DN40), approx. 30.5 kg (DN50), approx. 72 kg (DN80), approx. 74 kg (DN100)
Application scenarios
Continuous Condensate Drainage from Steam Heat Exchangers
Installed at the condensate outlet of steam heating equipment to discharge condensate generated during operation. The float mechanism responds to changes in condensate load, while the built-in thermodynamic automatic air vent device provides automatic air removal. DN25 to DN100 flanged sizes are available.
Condensate Drainage at Low Points or Dead Ends of Main Steam Pipelines
Installed at low points, dead ends or condensate collection locations in main steam pipelines to discharge condensate formed in the piping. The FT43 series uses flanged connections and is available in DN25 to DN100 sizes for compatible industrial steam piping.
Condensate Drainage from Heating Equipment Prone to Steam Lock
Installed at the condensate outlet of steam heating equipment where steam lock may occur. Select model FT43-C and use its manual steam lock release device to eliminate the steam lock and allow condensate to discharge.
Selection points
Optional vertical installation model
In addition to the standard horizontal installation model, FT43V is suitable for vertical installations with downward flow and can be selected according to the piping installation direction.
Optional steam-lock-breaking device for FT43-C
The FT43-C model is equipped with a manual steam-lock-breaking device, SLR, for applications where steam-lock risk exists.
Optional balance pipe or blowdown valve connection
A 3/8-inch BSP or 3/8-inch NPT threaded hole can be machined on the top or bottom of the valve cover as required for installing a balance pipe or blowdown valve.
Online maintenance supported
The product can be serviced without removing it from the piping.
BP99/32 capsule suitable for superheated steam
FT43 uses a BP99/32 capsule and can be used with superheated steam. At 0 bar g, a superheat level of 150°C is permitted.
Installation & maintenance notes
Follow the specified installation direction and flow direction for each model
Standard FT43 and FT43-C models should be installed horizontally according to the flow direction indicated on the valve body, with the float arm maintained in a horizontal position. FT43V should be installed with vertical downward flow.
Check the maximum differential pressure and limit the test pressure after installing internal components
Select the model according to its maximum differential pressure and confirm that the actual inlet-to-outlet differential pressure does not exceed the limit: FT43-4.5 is 4.5 bar, FT43-10 is 10 bar, and FT43-14 is 13 bar. The cold hydraulic test pressure can reach 24 bar g, but after the internal components have been installed, the test pressure must not exceed the valve's maximum differential pressure.
FAQ
What is the operating principle of the FT43 cast iron float steam trap?
The FT43 uses a float and main valve assembly to control the discharge of steam and condensate. When condensate is generated, the float sinks and opens the discharge path. When steam pressure increases or the water level falls, the float rises and closes the discharge path, maintaining continuous system operation.
What are the key installation requirements for this valve?
The valve is installed horizontally with a flanged connection. For DN80 or DN100 sizes, a 3/8-inch BSP or NPT threaded hole may be drilled in the cover when required for installing a drain valve. The float arm must remain horizontal to ensure that the float can move freely.
What are the applicable operating range and limit conditions of the FT43?
The design rating is PN16, with a maximum PMA of 16 barg, maximum TMA and TMO of 220°C, maximum PMO of 13 barg, and a cold hydraulic test pressure of 24 barg. The applicable operating range must be evaluated according to the system pressure and temperature conditions.
Which flange connection standards are available for this product?
The standard flange is EN1092 PN16 (DN80 and DN100). JIS/KS 10 flanged connections are also available to meet regional requirements.
What certificates and compliance documents are available?
An EN 10204 2.2 certificate can be supplied. Specify this requirement when ordering so that the certificate can be issued. CE marking can also be provided on request.
How does the FT43 operate, and what is its core function in steam trapping?
The FT43 has a cast iron body and built-in stainless steel components. It uses a float that automatically opens and closes the discharge path as the steam and condensate level changes, providing steam trapping together with air venting. Horizontal installation ensures that the float can move freely.
What are the key operating conditions and temperature considerations for the FT43?
The design rating is PN16, with a maximum TMA of 220°C. The maximum operating pressure, PMO, corresponds to ΔPMX for the relevant size. The minimum operating temperature is 0°C; consult the manufacturer for low-temperature service. Confirm the specific values according to the actual model and installation orientation.
What installation orientation requirements apply to the FT43 series?
For horizontal connections, the flow direction is from left to right for DN25 and from right to left for DN40 and DN50. For vertical connections, the flow direction is downward only. The float arm must remain horizontal to ensure free float movement.
What are the main differences between FT43-C and FT43?
The letter “C” in the FT43-C model designation indicates the steam lock release device (SLR) option. It is suitable for preventing steam lock in the system; the other construction features and options are the same as those of the FT43.
How can the required size and flange standard be confirmed for compatibility with an existing piping network?
Common sizes are DN25, DN40 and DN50. Available flange options include EN 1092 PN16, JIS/KS 10 and ANSI B 16.5 class 125. ANSI/JIS/KS flanges have threaded holes for convenient installation. Confirm the selection according to the site pipe size and connection method.