Two-Pipe Steam

Showing all 6 results

Showing all 6 results

Steam Heat Means Cast Iron

All our cast iron radiators work perfectly on steam heat. Browse our complete range of British-made cast iron radiators.

Browse All Cast Iron Radiators

Identifying a two-pipe steam radiator

In two-pipe steam installations, steam travels from the boiler to the radiators via an inlet pipe. After condensation, it returns to the boiler through a second outlet pipe. The distinguishing features of a two-pipe system include the presence of two pipes and the absence of a steam vent attached to the radiator, making identification straightforward.


two pipe steam mercury mid grey sparkle

Two-pipe steam radiator components

Steam enters the radiator through a control valve, while a steam trap facilitates the exit of air and water towards the boiler, ensuring steam remains trapped inside. As steam fills the radiator, air escapes through the open trap. Once fully saturated, the trap’s thermostat expands, sealing the outlet and preserving steam inside. Upon condensation, the trap reopens to allow water to return to the boiler. Air is vented through master vents near the boiler, and condensate flows back to repeat the cycle.

Control valves may be manual or thermostatic, with the latter providing enhanced comfort and control, contributing to energy efficiency and reduced fuel bills. Thermostatically-controlled radiators require a vacuum breaker, which we supply as standard. 

If you’re looking to spruce up your radiator, consider checking our our brackets and wall stays below.

Browse Brackets & Stays
lifestyle photo of mercury 4 column cast iron radiator in mid grey sparkle finish

Which radiators to use with two-pipe steam?

Cast iron remains the top choice for steam heating due to its resilience against temperature fluctuations, chemical variations in water, and potential steam hammer shocks. Its natural rust coating protects against oxidation, making it superior to thin-walled steel radiators with welded joins.

We exclusively offer cast iron radiators for steam systems. Opt for threaded, mechanical joins with steel or brass pipe for steam valve connections over compression fittings, ensuring durability.

Explore our steam radiator collection, and check out our pages on one-pipe steam and hydronic radiators for more insights.

Lifestyle photo of mercury 4 column cast iron radiator in bathroom with mid grey sparkle finish