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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 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. Also see STEAM VENTS - home and see RADIATOR STEAM VENTS, 1-PIPE 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:
I 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.
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
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.
Ken, you will want to check the Vent-Rite product literature but here's the basic difference between the Vent-Rite #1 and #11:
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
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.
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.
Honeywell Braukmann automatic valves on steam systems?
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).
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.
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.
Types & Properties of Steam Radiator Vents on 1-Pipe Steam Radiators
Details about 1 pipe steam heat radiator venting are at RADIATOR STEAM VENTS, 1-PIPE SYSTEMS. Here is a brief summary:
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