How do I select the correct differential pressure rating (4, 8, or 12 bar)?

Select based on your actual operating differential pressure across the trap—not the line pressure. Calculate the difference between inlet steam pressure and back pressure at the trap outlet. Choosing a trap rated for the correct ΔPMX ensures optimal condensate discharge without steam loss.

What is the recommended installation orientation for S and SF Series traps?

The trap must be installed with the body upright and the strainer cap at the bottom. This ensures the internal bucket rises and falls vertically for proper operation.

Are spare parts and repair kits available for field maintenance?

Yes. Spirax Sarco provides valve and seat assemblies (pre-assembled), bucket assemblies, strainer screens, and gasket packets. Order spares by stating the trap size, model number, and pressure rating.

Can I use these traps with superheated steam?

These traps are designed for saturated steam service. For superheated steam applications, consult PC Engineering to identify suitable alternatives or confirm operating limits.

What certifications are available for this product?

The S and SF Series comply with PED 2014/68/EU. Typical test certificates are available upon request—specify certification requirements at the time of order placement.

SPIRAX SARCO · STEAM TRAPS

Spirax Sarco S and SF Series Cast Iron Inverted Bucket Steam Traps

Name: Spirax Sarco S and SF Series Cast Iron Inverted Bucket Steam Traps
Brand: Spirax Sarco

Spirax Sarco S & SF Series inverted bucket steam traps - cast iron, PN16, for saturated steam systems. Available at PC Engineering India.

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Overview

The Spirax Sarco S and SF Series are robust inverted bucket steam traps designed for efficient condensate removal in saturated steam systems. Constructed with a cast iron body and cover conforming to DIN 1691 GG25, these traps deliver reliable performance in industrial steam applications up to 13 bar g operating pressure.

The inverted bucket mechanism operates on the principle of buoyancy—when steam enters the bucket, it floats and closes the valve; as condensate accumulates, the bucket sinks, opening the valve to discharge condensate. This proven design ensures minimal steam loss while effectively removing condensate and non-condensable gases.

Both S Series (screwed connections) and SF Series (integral flanged connections) include an integral strainer for protection against debris. The fully maintainable construction allows for easy inspection and replacement of internal components, reducing downtime during scheduled maintenance.

Key Features

Inverted bucket operating mechanism for reliable condensate discharge
Cast iron body and cover (DIN 1691 GG25) rated to PN16
Integral strainer included in all models
S Series: Screwed BSP or NPT connections (½" to 1½")
SF Series: Flanged EN 1092 PN16 connections (DN15 to DN40)
Stainless steel internals for corrosion resistance
Fully maintainable with readily available spare parts
Compliant with European Pressure Equipment Directive 2014/68/EU

Specifications

Parameter	Value
Body Material	Cast Iron DIN 1691 GG25
Internals	Stainless Steel (304/316L)
Design Pressure (PMA)	16 bar g @ 120°C
Max Operating Pressure (PMO)	13 bar g @ 195°C
Max Operating Temperature (TMO)	300°C @ 9.6 bar g
Min Operating Temperature	0°C
Max Differential Pressure (ΔPMX)	4, 8, or 12 bar (model dependent)
Screwed Sizes	½" (SA), ¾" (SB), 1" (SC), 1½" (SD)
Flanged Sizes	DN15 (SFA), DN20 (SFB), DN25 (SFC), DN40 (SFD)
Screwed Connections	BSP Rp (ISO 7-1) or NPT
Flanged Connections	EN 1092 PN16
Gasket Material	Reinforced exfoliated graphite
Standards	EN 1092, ISO 6552, PED 2014/68/EU
Size	A (mm)	B (mm)	C (mm)	D (mm)	E (mm)	Weight (kg)
½"	130	105	75	95	170	3.4
¾"	175	145	110	105	215	7.3
1"	205	155	130	120	250	10.5
1½"	245	180	195	150	345	19.0
Size	A1 (mm)	B (mm)	C (mm)	D (mm)	E (mm)	Weight (kg)
DN15	175	105	85	95	180	4.7
DN20	225	145	110	105	215	9.3
DN25	255	155	135	120	255	12.8
DN40	295	180	195	155	350	22.3

Applications

- Steam mains and distribution headers - Process heating equipment - Heat exchangers and unit heaters - Jacketed vessels and tanks - Tracer lines - General industrial steam systems in refineries, chemical plants, textile mills, food processing, and pharmaceutical manufacturing

Frequently Asked Questions

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Contact PC Engineering for pricing, availability, and technical support for Spirax Sarco S and SF Series Inverted Bucket Steam Traps. Call us or fill in our inquiry form — our engineers will respond within 24 hours.

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