Automatic / Thermostatic Radiator Valves
Automatic Hot Water & Steam Heat Radiator Valves

The radiator control valve opens or shuts to allow hot water or steam to enter and heat the radiator. An automatic or thermostatically controlled radiator valve allows you to set the desired room temperature.

The automatic hot water or steam radiator valve, thermostatically controlled, will automatically open or close to attempt to control room temperature to the desired level.

Keep in mind that with any heat control installed right at the radiator, the control will be sensing temperature in that location, not across the room, so some experimenting to find the best setting will be needed.

Armstrong Corp. [image at left] provides the RV-4 One-Pipe Steam Radiator Valve that operates as a room thermostat suitable for residential low-pressure steam heating systems.

By installing a thermostatically controlled steam vent at each radiator, every radiator can be controlled or set to the desired temperature.

There is a central advantage of thermostatically operated steam vents over swapping out the actual radiator control valve for a thermostatically controlled radiator valve, that is, they are easier and less disruptive to control.

The original steam vent is simply unscrewed and the new thermostatically controllable steam vent is screwed in at the same location.

Watch out: it's safer to install or change steam heating system parts when the system is not calling for heat and when the steam boiler and radiators are cold.

Don't be fooled. If your heating system is on and the steam boiler is hot, unscrewing the steam vent on a "cold" steam radiator will allow steam to rise into the radiator (forcing air out of the steam vent opening) and you could be seriously burned by rising steam.

Replacing Manual Radiator Valves with Thermostatically Controlled Radiator Valves

If you have to replace the control valve on a hot water or steam radiator or convector unit, consider installing a new valve that incorporates a thermostat as well.

Several companies provide thermostatically-controlled radiator valves including Armstrong, Danfoss, Hoffman Specialty, Jacobus (Maid'O'Mist) and others. The automatic radiator valve shown at left was observed on a typical modern European installation in Molde, Norway.

This (more expensive) radiator control valve lets you treat each individual radiator as a "heating zone".

As long as the room thermostat is calling for heat, each radiator can be regulated automatically when a thermostatic radiator valve (TRV) is installed..

Thermostatically-controlled Radiator Valve Sources & Manuals

• Danfoss ABNM RA-2000 valve is for use on hot water & steam systems.
• Danfoss ABRA RA2000 valve are used on some hot water and steam heating systems.
• DANFOSS: RA-N Radiator Valves with Integrated Presetting and Self-Sealing Tailpiece [PDF] data specifications and features, retrieved 2017/12/12 original source: http://heating.danfoss.com/PCMPDF/VDSXL202_RA_N_selfseal_teamc.pdf
• DANFOSS VHS valve for parallel and baseconnection radiators, with integral pre-setting and shut-off/drain device [PDF] - data specifications, control valve for modern base connection
  radiators, as well as for universal or bathroom radiators with connection distances of 50mm between flow and return.
  
  Contact Danfoss: Danfoss A/S Hårupvænget 11 Hårup DK-8600 Silkeborg Telefon: +45 86 80 36 66 Website: http://heating.danfoss.com/
  
  Boysen, Herman, K_v: What, WHy, How, Whence?, [PDF] Danfoss, (2011) retrieved 2017/12/12 original source: http://heating.danfoss.com/PCMPDF/VFHBG202_kv.pdf
• DANFOSS RA2000 RADIATOR VALVE INSTALLATION INSTRUCTIONS [PDF] usable on hot water & 2-pipe steam heating systems.
  
  Excerpts from product literature: RA 2000 Thermostatic radiator valves regulate the flow of hot water of hot water or steam through free-standing radiators, baseboards or convectors in hot water and two-pipe low pressure steam systems.
  
  RA 2000 Thermostatic Radiator Valves regulate the flow of hot water or low pressure steam through free-standing radiators, baseboards, or convectors in hot water and two-pipe steam systems.
  
  The Danfoss 013G8250 is the RA2000 Thermostatic Radiator Valve Operator with a valve mounted dial and a built-in sensor. The RA 2000 thermostatic operator consists of a saturated vapor charged bellows and a setting dial.
  
  The dial is set to the position equal to the desired temperature. When the ambient temperature lowers, the pressure from the bellows will reduce, allowing the valve to open.
  
  A rise of temperature increases the pressure in the bellows closing the valve. The balanced pressures between the adjustment spring and the bellows ensure a smooth and modulating operation of the valve.
• DANFOSS ZONE VALVES & RADIATOR VALVES SELECTION CHART [PDF]
• DRAYTON TRV4 THERMOSTATIC RADIATOR VALVE MANUAL [PDF] Drayton Controls, U.K., Sales Tel: +44 0 845 130 5522, Email: customer.care@invensys.com retrieved 2017/12/12 original source: http://www.draytoncontrols.co.uk/sites/default/files/TRV4%20%28U.%26I.%20Guide%29.pdf
• DRAYTON TRV5 THERMOSTATIC RADIATOR VALVE CATALOG [PDF] op. cit. original source: file:///Users/danielfriedman/Downloads/pa_457823.pdf
• Elgato Eve Thermo App-Enabled Thermostatic Radiator Valve (Appel HomeKit / Bluetooth) - may not be available
• HONEYWELL BRAUKMANN V2040HSL10 INSTALLATION INSTRUCTIONS [PDF]V-2000 series radiator valve (replaces the Honeywell V100 Series valve series), usable on 1-pipe steam heating system radiators and on hydronic heating systems. Note: this is a 1/8" 1 pipe steam radiator valve.
  
  Excerpt: One-Pipe Steam Thermostatic Radiator Valves - Allow automatic temperature control in one-pipe steam or hot water systems for free standing radiators, convectors and other heating units with standard capacity requirements. Provide comfort and energy savings.
  ...
  Adjustable balancing cartridge design made from resilient material (EPDM), ensures tight shut-off on steam and hot water systems.
• HONEYWELL T104 Controls & V110 Valve Body THERMOSTATIC RADIATOR VALVES [PDF] (1990) Honeywell Thermostatic Radiator Valves including the Honeywell Braukmann series straight and angled radiator valves are sold in a range of models and capacities. Retrieved 2017/12/12 original source: https://customer.honeywell.com/resources/techlit/TechLitDocuments/62-0000s/62-3004.pdf
• HONEYWELL T104A Thermostatic Control [PDF] (1994) Retrieved 2017/12/12 original source: https://forwardthinking.honeywell.com/related_links/water/thermostatic_radiator_valve/install/62_3046.pdf

Above: the a heating radiator above, installed at Vassar College, you can see not only the radiator control valve, more information as well.

Photo above: shown on the inlet end at the upper right of the radiator is a No. 8 / 3000-2 Piston Operator from Johnson Service Company, Milwaukee, now Johnson Controls. That control can contol steam or hot water flow into the radiator.

• Johnson Controls, PNEUMATIC VALVE ACTUATORS V-3000-8012 (Exposed) and V-3000-8003 (Enclosed) [PDF] Product Technical Bulletin (2016), Part No. 14-1078-22, Rev. D, Johnson Controls, copy on file as V-3000-8012-Valve-Johnson.pdf
  
  Excerpt: The V-3000-8012 and V-3000-8003 Pneumatic Valve Actuators are designed to accurately position steam or water valve modulating plugs in response to a pneumatic signal from a controller.
• SALUS PH60 Programmable Thermostatic Radiator Valve