Steam vent on a radiator (C) Daniel Friedman Steam Vent Types, Choices & Selection
Which steam vents are used where on 1 pipe or 2 pipe steam heating systems? Steam radiator vents; steam pipe vents; steam trap vents.
     

  • STEAM VENT TYPES, SELECTION - CONTENTS: steam heat vent types, different venting requirements for 2-pipe steam heat systems vs 1 pipe systems, location of vents on 2 pipe steam heat systems; steam line vacuum breakers, steam main vents
  • POST a QUESTION or READ FAQs about steam vent selection and installation; guides to steam vent models, features, choices, applications, manufacturers, sources
  • REFERENCES

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Steam vent types:

2 pipe steam vents vs 1 pipe steam heat system vents: this article describes the different types of vents used on two pipe and one pipe steam heating systems and explains why a 2-pipe steam heat system will generally require different vents at different locations from a 1 pipe system.

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Steam Vent Types, Applications, Choices & Selections

Adjustable steam vent helps regulate heat output (C) Daniel FriedmanAt left is the top of an adjustable steam vent. By adjusting between fast and slow you can regulate how quickly this steam radiator gets hot.

Steam radiator vents are found principally on one pipe steam heat radiators. Here we discuss the requirements, installation, and troubleshooting of steam vents on radiators as well as other steam vents found on steam piping and at other locations in steam heating systems for both one pipe and two pipe steam systems

[Click to enlarge any image]

Which Type of Steam Vent Should Install?

Reader Question: (2/28/2014) Mike said:

Can you tell me what the correct steam vent would be to use in a 2 pipe system? I just removed due to it leaking and after cleaning the rust off it I found it to be a Vent-Rite #1. Picked up a replacement and the literature said it's for a one pipe system. Also this radiator has a Braukmann auto valve on supply.

Reader Question (2/28/2014) Ken said:

Vent-Rite No. 11 Steam Vent - Vent-Rite Valve Corp. & InspectApedia.comI have a question about a Vent-Rite air valve. I had a Vent-Rite #11 air valve fail. I wanted to replace it in kind,but the suppliers around here only carry the Vent-Rite #1. I was wondering if anyone knows what setting on the #1 is equal to the #11.

I called Emerson Swan. No one was sure.One person said he thought it was full open (8) but I would have thought it would be more in the mid range.

Reply:

Shown at left: Vent-Rite # 11 steam vent intended for 1 pipe steam systems. [Click to enlarge any image]

Watch out: two pipe steam heat systems generally do not use the same steam vent models nor are vents at the same locations as steam vents found on one pipe steam heat system. Two pipe steam vents and the venting differences between one pipe and two pipe steam systems are discussed here.

Mike: Let's start with a general comment: a two pipe steam system carries steam up and condensate back in different pipes, using a thermostatic trap at the end of each radiator to discharge both air and water from the radiator. Simple texts like Weil McLain's study course simply state

Do not use air vents on two pipe steam heat systems" Instead yo use float and thermostatic (F&T) traps at the end of the system main. These are fast-acting traps that allow both air and condensate out of the system main.

It's therefore interesting that you found a steam vent on the radiator in your system - but then where was it installed? You can read about Vent-Rite steam vents at the company's site www.emersonswan.com but we will include details of two pipe steam vent selection in this article as well.

Compare the Vent-Rite #1 that you found on your system with the Vent-Rite #35 Steam Heat Main air valve.

  • The Vent-Rite #1 (or #11) is designed for 1-pipe steam systems and mounts on the radiator. A Vent-Rite #1 steam vent is shown in our photo above. The company describes their #1 vent as providing ... quick, uniform distribution of heat to all radiation ... This requires balancing the radiation by controlled venting.Vent-Rite #1 Non-Vacuum vents are adjustable and all vents are designed for positive action and straight-line venting. They function automatically to vent the air. If, through an unusual condition the vent is filed with water, the vent port automatically closes.

    The Vent-Rite #1 Air Elimination Valve VentRite No 1 for Steam Radiators ... has been designed to eliminate air in any one pipe steam radiator system as quickly as possible to assure rapid ad efficient heating. It will open and close all pressures up to 3 PSI Do not use at system pressure above 10 PsI This air valve is easily installed its [sic] standard 1/8" male connection makes it interchangeable with practically any other valve. It is fully adjustable, enabling the user to balance a system with a minimum of effort. Use for free standing radiators, one pipe steam radiator system. (Adjustable angle vent).

Ken, you will want to check the Vent-Rite product literature but here's the basic difference between the Vent-Rite #1 and #11:

  • The Vent-Rite #1 has a 3/32" vent port and operates at 3 psi.
  • The Vent-Rite #11 has a 1/16" vent port and operates at 6 psi. So I'm not sure that a #11 is a proper substitute for a #1.

    Both are still produced by the manufacturer. If I were attempting to use the #11 I'm guessing that you'd set it venting down to a reduced level to see how the radiators heat. But for a two pipe steam system other vent controls are needed.

So we see that the difference between the Vent-Rite #1 & #11 is the vent port size and operating pressure. It seems to me that as the #11 has a vent opening that is twice as large as the #1 (and is intended to handle twice the pressure range), if you needed the #11 in the first place, you'd try the #1 at wide open as the technician suggested.

Mike, since yours is a typical two pipe steam system it may be that the old Vent-Rite #11 that you removed was a mistake from the get go; according to the company it is intended for one pipe steam systems. It might have worked, somewhat, as it's a versatile valve, but that's not what the literature says works properly on two pipe steam systems.

You can ask the company for help: Vent-Rite Valve Corporation: 1875 Dewey Ave. Benton Harbor, MI 49022 TEL: (269) 925-8818 FAX: (269) 925-7888. In the article below we include Vent-Rite's table providing a steam vent replacement guide.

If venting is found inadequate you'll need to switch to the larger capacity #11 steam vent. Details are in the table given below and adapted from information from Vent-Rite and others.

Other Main Vents, Hoffman Steam Traps & Vacuum Breakers Used on 2-Pipe Steam Heating Systems

Vent-Rite No. 35 Steam Vent - Vent-Rite Valve Corp. & InspectApedia.comVent-rite advises: For venting basement mains use the Vent-Rite 35, 75, or 77 air valve or an equivalent from another manufacturer.

  • The Vent-Rite #31 & 33 are used on steam risers and on steam convectors.
  • The Vent-Rite #35 (shown at left), Vent-Rite No. 75, or Vent-Rite steam vent No. 77 are intended for main vents (two pipe systems and located on the mains). The Vent-Rite No. 35 shown in our photo is distributed on EBay by Barnes & Jones, Inc.

You will probably also find a Hoffman trap at the two pipe steam radiator outlet (below left) and one or more main steam line vents (photo below right).

Some two pipe steam systems also include a vacuum breaker in the main as well. That device allows air into the system when the system cools down after the boiler has shut off.

Basically, to work at all, steam systems have to let air in and out of the piping system. Air enters when the system cools (the burner is off) and air is forced out by rising steam when the system heats (burner is on and making steam). Rising steam works with air vents to allow steam into and air out of radiators during the heating phase. During the cooling phase air enters the system at vacuum breaking vents, air vents, and possibly at valve stems and other locations.

In a one pipe system the air escapes at a radiator-mounted steam vent.

In a two pipe system air escapes via the Hoffman steam trap (photograph at below left) or similar device at the radiator base (on the condensate return side of the radiator), as well as from vents along the main piping.

Hoffman steam trap (C) Daniel Friedman Steam vent on steam piping (C) Daniel Friedman

Honeywell Braukmann automatic valves on steam systems?

Honeywell Braukmann EA122A heating vent (C) InspectApedia One pipe steam radiator valve Honeywell V2043HSL (C) InspectApedia & HoneywellThe Braukmann automatic valve you cite as present on your system is a Honeywell product, though I don't know which product you found installed.

The Honeywell Braukmann EA122A1002 Automatic Air Vent shown at above left (if that's what you've got) is intended to vent air from high pressure mains and equipment in hot or cold water systems - this is a hydronic systems valve not a steam vent.

However we might find a hydronic (hot water heat) system air vent installed on a steam system in which a lower floor in the building is being heated by hot water from the boiler rather than by steam.

The company does produce thermostatic radiator valves that might be found on a steam or hot water heating system and also a Honeywell V2042HSL10 steam radiator valve used on one pipe steam systems and shown at above right. If yours is a two pipe steam system I would not expect you to find this valve installed.

If you can give me a photo or identifying markings I will explain further; most likely it's there to purge air from the steam main. Quoting: Continuing: Mike, I suspect that the old vent you removed was a mistake from the get go; it might have worked, somewhat, as it's a versatile valve, but that's not what the literature says works properly.

The Braukmann auto valve is a Honeywell product; if you can give me a photo or identifying markings on your Honeywell Braukmann I will explain further; most likely it's there to vent the steam main.

Or if you are talking about a radiator valve, the Honeywell Braukmann V110F, for example, is used on both hot water and two-pipe steam systems to provide individual radiator heat control (by thermostatic operation).

Contact

  • Vent-Rite Valve Corporation: 1875 Dewey Ave. Benton Harbor, MI 49022 TEL: (269) 925-8818
  • Emerson Swan, Inc., 300 Pond Street, Randolph, MA 02368, Tel: (781) 986-2000 Fax: (781) 986-2028, info@emersonswan.com - Emerson Swan is a nationally recognized, stocking manufacturer’s representative organization serving the northeastern United States and the Greater Toronto Area.

For steam vent troubleshooting also see STEAM VENTS where we discuss other steam vent problems such as cold radiators, banging pipes, noisy radiators, steam vents that spitting water, clogging steam vents, and steam vent replacement.

Types & Properties of Steam Vents on 1 & 2-Pipe Steam Systems

The following tables are adapted from product literature provided by Emersonswan.com, a provider of Vent-Rite steam vents for radiators, convectors, steam risers, main steam vents and vents for unit heaters.

Table of Non-Vacuum Vents & Their Applications & Substitution Part Numbers
Vent-Rite, Dole, & Hoffman Steam Vents 1

Application
Product Number
Connection
Vent Port Diam
Operating
Pressure
2
O.A. HT.
Adjustable?
Substitutes For
Vent-Rite vents for
Free-Standing Steam Radiators
No. 1
1/8" Male NPT
3/32"
3 psi
3 1/4"
Yes
Dole #1A
Hoffman# 1A
No. 11
1/16"
6 psi
2 3/4"
 
Dole #1933
Hoffman#40
Vent-Rite
Convector Heaters
Steam Risers
No. 31 1/8" Male 1/16"1/16" 6 psi 3 3/4"   Dole #3A
Hoffman# 41
No. 33 1/4" Male   Dole #3B
Hoffman #43

Vent-Rite
Main Steam Vents

No. 35 3/4" Male x 1/2" Female NPT 3/32" 3 psi 3 1/4"   Dole #4
Hoffman #45
No. 75 5 psi 4 5/8"   Dole #3C
Hoffman #45
No. 77 1/8" 3 1/2 psi   Dole #5
Hoffman #45
Vent-Rite Unit Heater Steam Vents No. 57 3/4" Male x 1/2" Female NPT 1/32" 20 psi 4 5/8"   Dole #55
Hoffman #77
Hoffman Steam Air Line Valve No. 3            

THERMOSTATICALLY-CONTROLLED

No-Float type vents

             

2-Pipe Steam Radiator Valves & Traps

See
STEAM TRAPS
and
RADIATOR VALVES & HEAT CONTROLS
and
STEAM VENTS THERMOSTATICALLY CONTROLLED

             

Notes:

1. Adapted from "Air Valve for Steam Systems", Emerson Swan (Vent-Rite), Vent-Rite Valve Corporation: 1875 Dewey Ave. Benton Harbor, MI 49022 TEL: (269) 925-8818 FAX: (269) 925-7888 retrieved 2/28/2014, original source www.emersonswan.com/ckfinder/userfiles/ files/Vent-Rite%20Literature%281%29.pdf

2. Operating pressure drop ("drop away") is the maximum pressure at which the vent will continue to open and close due to the change of temperature. The vent may be used with slightly higher pressure provided it drops below the operating pressure between each firing cycle.

Types & Properties of Steam Radiator Vents on 1-Pipe Steam Radiators

Steam radiator (C) Daniel FriedmanAt left our photo illustrates a 1 pipe steam system with a typical radiator vent.

Details about 1 pipe steam heat radiator venting are at RADIATOR STEAM VENTS, 1-PIPE SYSTEMS. Here is a brief summary:

  • Thermostatically-controlled no-float steam vents (THERMOSTATICALLY-CONTROLLED)
  • Float-type steam vents: an water+alcohol-filled float inside the steam vent heats, rises, and closes the vent as the radiator heats. The float also rises to prevent water from spitting out of the vent should condensate rise inside the radiator or vent.

    On FLOAT-TYPE steam vents (as well as most others) rust or sediment can clog the float vent opening and interfere with its proper operation. Excessive steam pressure can also prevent the vent from operating properly.
  • Adjustable steam vents operate similarly to the float-type steam vents described above, but add the feature of ADJUSTABLE air vent opening size so that the air venting rate can be better matched to the radiator size. (Larger steam radiators need a larger air vent opening.)

    Examples of adjustable steam vents include: Hoffman Model 1A (Part No. 401422) adjustable air valve with 6 settings (1-slow to 6-fast venting); VariValve® Quick-Vent. Those vents are designed for traditional steam radiators. If your steam heat is by a steam convector unit, different steam vents are required, such as the Hoffman Specialty Model 1B (Part No. 401425).
  • Adjustable-Thermostatically-operated steam vents (ADJUSTABLE THERMOSTATICALLY OPERATED) include an adjustable room temperature thermostat that allows the occupant to set the desired room temperature.

    Setting this thermostatically operated steam vent control actually adjusts the rate at which the vent permits air to escape from the individual radiator, similar to the adjustable steam vents described above, but in this case once the thermostat is set, the automatically regulating steam vent is responding to the room temperature setting.

Reader Question: which steam vent to use on a 2 pipe steam heat system

(Feb 28, 2014) Mike said:
Can you tell me what the correct steam vent would be to use in a 2 pipe system? I just removeddue to it leaking and after cleaning the rust off it I found it to be a Vent-Rite #1. Picked up a replacement and the literature said it's for a one pipe system. Also this radiator has a Braukman auto valve on supply.

Reply:

Thanks for the question, Mike. I will work on adding detail about proper venting for two-pipe steam systems and how air venting is different from one pipe steam, and will add that to the article series.

Meanwhile a general comment: a two pipe steam system carries steam up and condensate back in different pipes, using a thermostatic trap at ehe end of each radiator to discharge both air and water from the radiator. Simple texts like Weil McLain's study course simply state "Do notuse air vents on two pipe steam heat systems" Instead yo use float and thermostatic (F&T) traps at the end of the system main. These are fast-acting traps that allow both air and condensate out of the system main.

It's therefore interesting that you found a steam vent on the radiator in your system - but then where was it installed? You can read about Vent-Rite steam vents at the company's sige www.emersonswan.com

Compare the Vent-Rite #1 with the Vent-Rite #35 Steam Heat Main air valve. The Vent-Rite #1 (or #11) is designed for 1-pipe steam systems and mounts on the radiator. The Vent-Rite #35,75, or 77 are intended for main vents (two pipe systems and located on the mains); The Vent-Rite #31 & 33 are used on steam risers and on steam convectors. Contact the company for help or to download their product guide.

Emerson Swan, Inc.
300 Pond Street
Randolph, MA 02368
Tel: (781) 986-2000
Fax: (781) 986-2028
info@emersonswan.com

Continuing: Mike, I suspect that the old vent you removed was a mistake from the get go; it might have worked, somewhat, as it's a versatile valve, but that's not what the literature says works properly.

The Braukman auto valve is a Honeywell product; if you can give me a photo or identifying markings I will explain furhter; most likely it's there to purge air from the steam main. Quoting: Continuing: Mike, I suspect that the old vent you removed was a mistake from the get go; it might have worked, somewhat, as it's a versatile valve, but that's not what the literature says works properly.

The Braukman auto valve is a Honeywell product; if you can give me a photo or identifying markings I will explain furhter; most likely it's there to vent the steam main.

Or if you are talking about a radiator valve, the Honeywell Braukmann V110F, for example, is used on both hot water and two-pipe steam systems to provide individual radiator heat control (by thermostatic operation).

And for completeness I add further that some two pipe steam systems also include a vacuum breaker in the mains. That device allows air into the system when the system cools down after the boiler has shut off. Basically steam systems let air in and out; rising steam combined with air vents allow steam in and air out of radiators. In a one pipe system the air escapes at a radiator-mounted steam vent; in a two pipe system air escapes via the Hoffman trap or similar device at the radiator base (on the condensate return side of the radiator), as well as from vents along the main piping.

 

Continue reading at STEAM VENTS, AUTOMATIC where we describe just about every type of automatic steam vent used on residential and most commercial systems. or select a topic from the More Reading links shown below.

Or see STEAM RADIATOR VENT REPAIR

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STEAM VENT TYPES, SELECTION at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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