When should I use an automatic pump trap instead of a standard steam trap?

Use an automatic pump trap when condensate cannot drain by gravity alone—typically when the return line is elevated, backpressure exceeds steam pressure, or the system operates under vacuum or stall conditions. The APT10-4.5 handles all these scenarios without requiring electrical power.

What is the minimum installation head required for the APT10-4.5?

The minimum installation head from the base of the pump to the condensate outlet is 0.2 metres, though Spirax Sarco recommends 0.3 metres for optimal performance.

How do I calculate if the APT10-4.5 will work for my backpressure conditions?

Total backpressure must be below motive steam pressure. Calculate BP = (H × 0.0981) + P + Pf, where H is lift height in metres, P is return line pressure in bar g, and Pf is downstream friction loss. Ensure this value stays below 4.5 bar g.

What spare parts are available for maintenance?

Spirax Sarco supplies spare kits including cover gasket, inlet check valve, spring and actuator arm, float assembly, trap and outlet check valve mechanism, and inlet/exhaust valve and seat kit. A motive supply strainer is also available separately.

Can this pump trap be certified for specific project requirements?

Yes, the APT10-4.5 is available with EN 10204 3.1 certification. All certification and inspection requirements must be stated at the time of order placement.

SPIRAX SARCO · STEAM TRAPS

Spirax Sarco APT10-4.5 Automatic Pump Trap – Steam Operated Condensate Removal

Name: Spirax Sarco APT10-4.5 Automatic Pump Trap – Steam Operated Condensate Removal
Brand: Spirax Sarco

Spirax Sarco APT10-4.5 Automatic Pump Trap for condensate removal in steam systems. PN10 rated, handles vacuum to 4.5 bar g.

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Overview

The Spirax Sarco APT10-4.5 is a steam-operated automatic pump trap designed for reliable condensate removal from process and heating plant. This displacement receiver combines the functions of a steam trap, pump, and check valves into a single PN10-rated unit, eliminating the need for external seals or glands.

The APT10-4.5 operates without electrical energy, using motive steam pressure to automatically switch between trapping and pumping modes based on line conditions. This makes it suitable for applications where condensate must be removed under varying pressures, including vacuum conditions. The unit requires a minimum installation head of just 200 mm from its base.

Available in standard blue paint finish or Electroless Nickel Plate (ENP) coating for corrosive environments, the APT10-4.5 is constructed with an SG iron body and stainless steel internal components for long service life in demanding industrial applications.

Key Features

Automatic switching between trapping and pumping modes based on line conditions
No electrical power required – fully steam operated
Handles vacuum through to positive pressure conditions up to 4.5 bar g
Integrated pump, trap, and check valve mechanisms in single body
Swing-type inlet check valve and ball-type outlet check valve
Stainless steel float and internal mechanism for corrosion resistance
Minimum 200 mm installation head requirement
Available with EN 10204 3.1 certification

Specifications

Parameter	Value
Size	DN20 x DN20
Body Design Rating	PN10
Maximum Motive Inlet Pressure	4.5 bar g
Maximum Operating Pressure	4.5 bar g
Maximum Backpressure	4.0 bar g
Operating Temperature Range	-10°C to 155°C
Ambient Temperature Limits	-10°C to 200°C
Cold Hydraulic Test Pressure	15.0 bar g
Pump Discharge per Cycle	2.6 litres
Max Trapping Capacity*	830 kg/h
Max Pumping Capacity*	650 kg/h
Minimum Installation Head	0.2 m (0.3 m recommended)
Weight (Approximate)	14 kg
Body Material	SG Iron EN JS 1025 / ASTM A395
Internals Material	Stainless Steel (various grades)
Inlet/Outlet Connections	BSP (BS 21 parallel) or NPT
Design Compliance	A.D. Merkblatter / ASME VIII

Applications

The APT10-4.5 Automatic Pump Trap is engineered for condensate drainage in:

- Process heating systems – shell and tube heat exchangers, jacketed vessels, reactors - HVAC and building services – air handling units, unit heaters operating under vacuum or stall conditions - Steam-heated dryers and coaters – paper, textile, and converting industries - Food and beverage processing – pasteurizers, cookers, and sterilizers requiring reliable condensate removal - Pharmaceutical manufacturing – process equipment where stall or vacuum conditions occur - Any installation where gravity drainage is insufficient and condensate must be lifted or pumped against backpressure

Frequently Asked Questions

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Contact PC Engineering for pricing, availability, and technical support for the Spirax Sarco APT10-4.5 Automatic Pump Trap. Call us or fill in our inquiry form — our engineers will respond within 24 hours.

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