Product Overview

Spirax Sarco TD25 and TD25F Thermodynamic Steam Traps are specifically designed for low capacity steam mains and tracer lines, also suitable for other industrial applications within their specified pressure, temperature and capacity ranges. Maximum working pressure is 25 bar g, maximum allowable temperature reaches 400°C, capable of handling demanding industrial steam system conditions.

Optional insulating hood is available to effectively prevent excessive heat loss when the steam trap is exposed to cold environments or rain and wind, thereby preventing excessive cycling and improving equipment operational stability and service life.

Technical Specifications

Maximum Body Design Conditions

Design Parameter	Value
Max. Allowable Pressure (PMA)	40 bar g
Max. Allowable Temperature (TMA)	400°C
Max. Working Pressure on Saturated Steam (PMO)	25 bar g
Max. Working Temperature (TMO)	400°C
Max. Cold Hydraulic Test Pressure	60 bar g

Critical Operating Limitation

During operation, maximum working backpressure must not exceed 80% of inlet pressure, otherwise the steam trap will not close properly.

Pressure Temperature Operating Range

Sizes and Connections

Available Sizes

Supports DN15, DN20, DN25 three size specifications to meet different pipeline installation requirements.

Connection Types

• Threaded Connection: 1/2", 3/4", 1" BSP or NPT thread standards
• Flanged Connection: EN1092/ISO7005 standard, PN25 pressure rating screwed flanges

Product Structure

Materials of Construction

No.	Part Name	Material Standard	Material
1	Body	ASTM A743 Gr.CA40F	Stainless Steel
2	Cap	AISI 416	Stainless Steel
3	Disc	BS 1449 420 S45	Stainless Steel
4	Strainer	BS 1449 304 S16	Stainless Steel
5	Strainer Cap	AISI 416	Stainless Steel
6	Strainer Cap Gasket	BS 1449 304 S16	Stainless Steel
7	Insulating Hood (Optional)	-	Aluminium
8	Flange	-	Carbon Steel

Dimensions and Weights

Dimensions/Weights (Approximate)

Size	A1	A	B	C	D	E	F	G	H	Weight-Flanged	Weight-Threaded
DN15	78	150	55	41	40	80	57	38	52	2.4 kg	0.75 kg
DN20	85	150	60	44	40	100	57	38	52	3.1 kg	0.95 kg
DN25	95	160	65	48	40	100	57	38	58	4.2 kg	1.50 kg

Note

Dimensions in mm, weights are approximate values, refer to actual product for installation.

Capacity Characteristics

Safety Information

Pressure Safety

• Before steam trap maintenance, confirm if there is residual fluid in the pipeline
• Isolation valves upstream and downstream must be closed, ensure pressure is fully released, pressure relief can be achieved using Spirax Sarco DV type relief valve
• Even if pressure gauge reads 0, do not assume system is fully depressurized, proceed with caution

Temperature Safety

• After closing valves, allow sufficient time for equipment to cool to avoid burn hazards from high temperature
• Wear appropriate protective clothing during operation, including safety glasses and other protective equipment

Installation Instructions

Basic Installation Requirements

1. Preferably install steam trap on horizontal piping with a short drop leg upstream
2. Isolation valves must be installed for future maintenance and replacement
3. Install appropriate detection devices (such as sight glass or spiratec system) to monitor trap operation
4. Sight glass should be installed at least 1 meter downstream of blast discharge traps
5. If discharging to closed return system, install check valve downstream to prevent backflow
6. Remove all packaging and protective caps before installation, ensure all connections are clean and unobstructed
7. Slowly open isolation valve until normal operating conditions are reached to avoid system shock
8. After installation, check for leaks and verify proper operation
9. Use correct tools, safety measures and protective equipment during operation

Installation with Insulating Hood

• If product is equipped with insulating hood, remove the hood first before loosening the cap with a standard spanner
• Never use adjustable wrenches or pipe wrenches on the cap to avoid damaging it

Maintenance

Disc and Seat Maintenance

1. For minor wear on disc and seat surfaces, use lapping compound with a figure-of-eight motion to lap the disc and seat separately
2. For severe wear that cannot be repaired by lapping, machine and polish the seat surface and replace with a new disc
3. Lapping depth must not exceed 0.25mm to avoid affecting sealing performance
4. During reassembly, the grooved face of the disc must contact the seat face, no gasket required when tightening the cap, but apply suitable high-temperature grease

Strainer Cleaning and Replacement

1. Use a spanner to loosen the strainer cap and remove the strainer for cleaning
2. If strainer is damaged, replace with a new one
3. During reassembly, insert the strainer into the cap, then screw into the body
4. Apply a small amount of molybdenum disulphide lubricant to the thread lead before assembly, ensure gasket surface is clean
5. Tighten strainer cap to recommended torque to ensure reliable sealing

Recommended Tightening Torques

Part No.	Size	Tightening Torque (N·m)
2	36	135-150
5	32 (M28)	170-190

Spare Parts

Available Spare Parts

Spare Part Name	Part No.	Notes
Disc (Set of 3)	3	Core sealing component
Strainer and Gasket	4, 6	Filter and sealing assembly
Insulating Hood	7	Optional accessory
Strainer Cap Gasket (Set of 3)	6	Sealing spare

Note

Solid lines in diagram indicate available spare parts, dashed lines indicate parts not available as spares.

Ordering Information

Product Ordering Example

1-Spirax Sarco TD25 Thermodynamic Steam Trap, BSP Threaded Connection

Spare Parts Ordering Requirements

1. Order by spare part name as listed, specifying steam trap size and model
2. Spare parts ordering example: 1-Strainer and Gasket for 1" TD25 Thermodynamic Steam Trap

Disposal

This product can be recycled. Disposal according to standard procedures will not cause ecological problems and meets environmental requirements.