CONDENSATE RETURN PIPES, PUMPS, STEAM - CONTENTS: Condensate Return Pumps & Condensate Systems on Residential Steam Heating Systems - how to identify & troubleshoot steam condensate return piping. Sources of trouble in the Steam Condensate System; corrosion on Steam Piping & Corrosion Control by Chemical Treatment of Condensate or Water. Leaks in steam condensate return piping. Steam condensate reservoirs & steam condensate pumps, problems with.
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Steam heating system condensate pumps & piping: this article describes and illustrates steam condensate return piping, condensate return pumps and steam condensate return reservoirs. We also discuss leaks in steam condensate piping lines and chemical treatment of steam condensate.
Our photo at left illustrates a steam condensate return pump system in a New York home.
Where condensate is unable to flow by gravity back to the steam boiler, a reservoir tank (under our client's hand at left) receives condensate from a low point in the building.
A float control and small pump moves condensate back to the steam boiler. In the condensate receiver system shown at left and on similar systems we have inspected in which the steam boiler is not even in the same building as the condensate receiving system, a control on the receiver sends water back to the boiler,
Watch out: where a separate condensate receiver is used, a feed pump to move condensate back to the boiler must be energized by a boiler-mounted condensate return pump controller. - Weil McLain 78
This steam system includes a plastic tank and injector pump used for chemical treatment of the steam condensate. When the float in the condensate return tank activates the condensate return pump, that same circuit activates the small chemical injector pump mounted on top of the plastic reservoir at the right in our photograph.
Some Sources of Trouble in the Steam Condensate System
Watch out: problems such as blockages or leaks in steam condensate return systems can have various causes and can originate in many areas including at least these:
Improperly sloped or routed condensate return piping can prevent condensate from returning to the boiler or can create blockages in piping that prevent steam heat from serving some radiators or building areas.
A steam trap that is not working properly - see STEAM TRAPS
A wiring error or electrical failure that causes the condensate pump to run backwards
A system operating problem (such as bad steam vents) or other events (a leak) or conditions (water chemistry or poor maintenance) that causes too-frequent in-feed of water to the boiler, leading to corrosion and leaks in the condensate piping or in the boiler itself
Improperly set or damaged boiler water feeder or water level controls
Condensate reservoir leaks
Condensate pump motor troubles: motor not running, won't start, won't stop running, noisy
Check for a dirty or clogged strainer blocking condensate flow in the reservoir or at the pump
If the pump wont' stop running check for a leaky failed steam trap (s) or a valve that has been left partly closed or is debris-clogged in the condensate discharge line; also check for a broken or debris-clogged pump impeller.
Dirt or debris blockages at steam traps, or anywhere in the condensate return system piping, including at the Hartford Loop
Corrosion on Steam Piping & Corrosion Control by Chemical Treatment of Condensate or Water
Our second steam condensate return system (left) shows the reservoir and condensate pump motor (grey pump and new piping on the right side of the condensate reservoir at the left in that picture).
Steam condensate may be corrosive due to an improper pH level of the building water supply, or condensate water may be particularly corrosive to steam piping or to the boiler itself due to the formation of carbonic acid in the condensate liquid.
Carbonic acid itself forms because of the combination of high levels of carbon dioxide CO2 and oxygen in the steam piping system. Steam piping that is made of copper is also vulnerable to a combination of ammonia and oxygen in the steam condensate.
Chemical treatment of steam condensate is typically done to reduce corrosion in the steam piping.
Other chemical treatments of water in steam boilers may be performed at the boiler itself to adjust the pH of the water or to control levels of corrosive carbonic acid using neutralizing amines or to control oxygen levels. 
A second approach to controlling steam system corrosion used particularly in steam systems that use a high volume of make-up water is the use of filming inhibitors or filming amines.
In a third approach to controlling steam system corrosion, water entering steam boilers may also be "de-aerated" by a feed water heater that removes excess oxygen mechanically.
Where do corrosion and leaks most often appear in steam piping?
Corrosion in steam piping is most likely to appear in the sections of steam condensate piping that remain filled with condensate. Those piping sections are found near the steam boiler itself or at steam condensate return reservoirs and pumps.
To control or reduce the corrosion and leaks caused by corrosive steam condensate the steam boiler water may be pre-treated or the condensate may itself be treated as we illustrate in our photo above.
Leaks in Steam Condensate Return Piping
Our photograph at left shows a leaky steam condensate return line close to the steam boiler.
This steam condensate line leak has been dripping for more than a decade. Unlike a hydronic heating boiler system, because the pressure in the steam condensate return line is low, the leak was not noticed by the homeowner and it was ignored by the heating service technician.
While not all of the piping is clearly visible in this image, you are also looking at part of
a HARTFORD LOOP.
Because steam condensate may be quite corrosive in steam heating systems commercial systems and some residential steam heat systems use additives or water conditioners to minimize those effects. Without the Hartford Loop properly sized and piped at the condensate return to the boiler, complete loss of boiler water could follow a leak in the condensate line.
In turn, loss of boiler water can destroy the boiler or can lead to catastrophic
Our opinion was that the piping in this steam condensate line section all should be replaced, but it was reasonable to wait until the end of the heating season rather than having to shut down the heater during freezing-cold weather.
Watch out: never pick at corrosion on a heating pipe: we warned the homeowner not to poke or pick at the corrosion on this piping. Disturbing the condensate return pipe was likely to result in a sudden and much larger leak that could leak badly, resulting in basement water problems and increased steam boiler water consumption.
Watch out: a leak in the condensate piping of a steam heating system can lead to very expensive damage including:
Leaks into the building causing rot, inviting insect damage, or leading to a costly mold cleanup job
Excessive water in-feed to the boiler, leading to increased rate of corrosion in the condensate piping or even the boiler itself, risking the development of additional leaks that can destroy the boiler
More details about steam condensate return pumps for residential properties are in process, photo contributions needed. CONTACT us.
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Questions & answers or comments about the causes & cures of trouble with steam condensate piping, pumps, reservoirs.
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
 Boiler Systems, Chemical Treatment, Association of Water Technologies, Technical Manual, web search 04/22/2011, original source: http://www.steamforum.com/pictures/water%20treat%20Boilers%281%29.pdf
 "Steam/Condensate Treatment, An Overview of Monitoring and Treatment", John J. Baum, Craft Products Co., Inc., White Paper prepared for P.C.I. Controls and Instrumentation, Seminar, August 1995, web search 04/23/2011, original source: http://www.craftprod.com/research/Steam%20-%20Condensate%20Treatment.pdf
Weil McLain Model 78 Boiler Manual, Boiler for gas, light oil, Gas/Light Oil fired BUrners, Installation, Start-up, Parts, Maintenance instructions, Part No. 550-141-705/0600, Weil-McLain Administrative Office, 999 McClintock Drive, Suite 200, Burr Ridge, IL 60527
Tel: 855-248-1777 Consumer Inquiries: 800-368-2492 Technical Services: 800-526-6636 Technical Support for Contractors Only.
If you are a homeowner and are experiencing a problem with your Weil-McLain equipment, the first step you must take is to contact your installer or locate an HVAC contractor in your area. Website: http://www.weil-mclain.com
"The Fight Against Corrosion - A Study of the Nature of Corrosion and its Problems in Water Services and Heating Systems", Daniel Davies, Research and Development Services, Stansted Mountfichet, Essex, England, World Plumbing Conference-IV, "Plumbing and the World Environment, Compendium of Workshop Papers, October 3-6, 1996, Hyatt Regency Chicago, Chicago, IL", [personal correspondence, DJF - Author, July 2011]
For details about the controls, components and switches commonly found on hot water heating systems see the articles listed below in which we explain how to identify, set, re-set, repair, replace, or avoid problems with the components of a hot water heating system..
The Steam Book, 1984, Training and Education Department, Fluid Handling Division, ITT [probably out of print, possibly available from several home inspection supply companies] Fuel Oil and Oil Heat Magazine, October 1990, offers an update, (see next item in this list). ITT Fluid Technology,
1133 Westchester Avenue
White Plains, NY 10604,
tel +1 914 304 1700 fax +1 914 696 2950 www.ittfluidbusiness.com
Principles of Steam Heating, $13.25 includes postage. Fuel oil & Oil Heat Magazine, 389 Passaic Ave., Fairfield, NJ 07004.
Domestic and Commercial Oil Burners, Charles H. Burkhardt, McGraw Hill Book Company, New York 3rd Ed 1969.
National Fuel Gas Code (Z223.1) $16.00 and National Fuel Gas Code Handbook (Z223.2) $47.00 American Gas Association (A.G.A.), 1515 Wilson Boulevard, Arlington, VA 22209 also available from National Fire Protection Association, Batterymarch Park, Quincy, MA 02269. Fundamentals of Gas Appliance Venting and Ventilation, 1985, American Gas Association Laboratories, Engineering Services Department. American Gas Association, 1515 Wilson Boulevard, Arlington, VA 22209. Catalog #XHO585. Reprinted 1989.
The Steam Book, 1984, Training and Education Department, Fluid Handling Division, ITT [probably out of print, possibly available from several home inspection supply companies] Fuel Oil and Oil Heat Magazine, October 1990, offers an update,
Principles of Steam Heating, $13.25 includes postage. Fuel oil & Oil Heat Magazine, 389 Passaic Ave., Fairfield, NJ 07004.
The Lost Art of Steam Heating, Dan Holohan, 516-579-3046 FAX
Principles of Steam Heating, Dan Holohan, technical editor of Fuel Oil and Oil Heat magazine, 389 Passaic Ave., Fairfield, NJ 07004 ($12.+1.25 postage/handling).
"Residential Hydronic (circulating hot water) Heating Systems", Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
"Warm Air Heating Systems". Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
Heating, Ventilating, and Air Conditioning Volume I, Heating Fundamentals,
Boilers, Boiler Conversions, James E. Brumbaugh, ISBN 0-672-23389-4 (v. 1) Volume II, Oil, Gas, and Coal Burners, Controls, Ducts, Piping, Valves, James E. Brumbaugh, ISBN 0-672-23390-7 (v. 2) Volume III, Radiant Heating, Water Heaters, Ventilation, Air Conditioning, Heat Pumps, Air Cleaners, James E. Brumbaugh, ISBN 0-672-23383-5 (v. 3) or ISBN 0-672-23380-0 (set) Special Sales Director, Macmillan Publishing Co., 866 Third Ave., New York, NY 10022. Macmillan Publishing Co., NY
Installation Guide for Residential Hydronic Heating Systems
Installation Guide #200, The Hydronics Institute, 35 Russo Place, Berkeley Heights, NJ 07922
The ABC's of Retention Head Oil Burners, National Association of Oil Heat Service Managers, TM 115, National Old Timers' Association of the Energy Industry, PO Box 168, Mineola, NY 11501. (Excellent tips on spotting problems on oil-fired heating equipment. Booklet.)
Links to our list of additional information on heating system inspection, repair, maintenance
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.
Carson Dunlop, Associates, Toronto, have provided us with (and we recommend) Carson Dunlop Weldon & Associates' Technical Reference Guide to manufacturer's model and serial number information for heating and cooling equipment
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.