Wall convectors are often used for both heating and cooling in commercial installations
and high-rise apartment buildings. The unit shown above has its own compressor mounted right in the cabinet, visible at lower center in
Wall-mounted heating and cooling convector installations may be designed with one central heater or
cooling system which feeds multiple units with chilled or heated water
or possibly refrigerant from a single remote heating and cooling heat pump.
Air Conditioner or Heater Wall Convector Unit Blower Fan Inspection & Diagnosis
Wall-mounted heating and cooling convector installations may be designed with one central heater or
cooling system which feeds multiple units with chilled or heated water
or possibly refrigerant from a single remote heating and cooling heat pump.
Above is an enclosure for a Command Aire wall convector heating or cooling convector unit, ca 1980. You won't know just what's installed inside that cover without a bit of further investigation. We discuss this unit and its identification
at DATA TAGS on AIR CONDITIONERS.
Our photo (above left) illustrates dual squirrel cage blower fans typically found in the bottom of a fan/convector heating or cooling unit such as this one found in a New York City apartment.
If the convector fan motors run and the squirrel cage fans spin but not enough air is coming out of your convector unit, turn off power and take a closer look at the fan blades themselves - you may need a flashlight and a mirror to make this check without disassembling the unit further than shown here (we removed the convector unit cover).
Dirt on the fan blades can significantly reduce airflow through the unit. Also check the cooling or heating coil fins for blockage by dust and debris - a more common source of air flow blockage at heating and cooling convector units like the one shown.
Our photo (above left) illustrates a condensate handling problem in the cooling convector unit for the same apartment unit introduced above.
Air conditioning condensate was leaking inside of the convector unit due to a clogged condensate drain line.
The condensate leak exited the bottom of the convector, ran through a raised floor cavity, entered apartment building walls, and ran around the wall interiors in a metal stud-framed wall sill plate where it led to major toxic mold contamination over a wide area, floor damage, and the need for costly cleanup and repair work.
While wall convectors are widely used for combination heating and cooling systems, their energy sources vary and include chilled water as well as refrigerant for cooling, while the heat source in a wall-convector may be forced hot water, gravity hot water, steam, or the unit may be heated by electricity. Many small wall convectors and some other convector units may incorporate a blower fan to increase the heat output from the device.
Above, courtesy of Carson Dunlop Associates, a Toronto home inspection & education firm, we see a schematic of how a wall-mounted heating or cooling convector unit works. This unit is passive, operating by simple convection. The heat source in a wall-convector may be forced hot water, gravity hot water, steam, or the unit may be heated by electricity.
Above is a traditional hydronic heating system wall convector and inside we give a closer view of the heat exchanging finned tubing that warms air that moves by convection across that component. These photos were taken in a 1920's home in Poughkeepsie New York. A heating convector unit operates much like a radiator (page top photo) but instead of thick cast iron used to radiate heat, the convector is made of copper tubing covered with metal fins, or of cast iron with cast-in fins.
Our photo (above) shows a leaky heating convector that was recessed into the wall. While recessed heating convectors were popular for aesthetic reasons (no radiator projects into the room), often a high percentage of the heat is flowing through the exterior wall to outside.
Our photo illustrates a steam-heated wall convector unit in a 1960's home found in New York. Steam convectors operate much like the hot water convector shown earlier but will include different relays and controls to manage the heat output of the unit. This heating convector was wall-recessed and included an electrical blower fan.
Electric-heated wall convectors and some other convector units may incorporate a blower fan to increase the heat output from the device. Our photographs of a wall-mounted heating convector (above) show a wall unit that is heated by steam.
Conventional wall-mounted heating convectors (units that do not include a fan or blower) rely on natural movement of warm-air upwards to draw cooler air in from the floor level.
You'll notice that there is a very generous air intake space along the bottom of the convector - it is designed to move plenty of air across its heating coil. As the convector gets hot, cool air is drawn up from floor level, is heated by the fins on the convector, and warm air is supplied out of the convector's front grille.
Watch out: if the convector fins are blocked by dust and debris or if the air inlet or outlet at the convector bottom or top are blocked by modifications, carpeting, furniture, the heating or cooling output of the device will be very significantly reduced. We discuss this problem in more detail
at RADIATOR BASEBOARD or CONVECTOR COVERS.
Below we provide articles that help in diagnosing and repairing no-heat problems with each of these types of heat delivery systems.
Electrically-heated, steam heated, or hot water heated fan convector heating units similar to what you see in our photos here but boosted by a fan that blows room air across the heater are discussed
at FAN CONVECTOR HEATERS - HYDRONIC COILS.
Wall Heating Convector Heater Maintenance
Once every year or so, we like to take the covers off of heating convectors to inspect the unit for leaks.
While we're at it, we make certain that the heat exchanging fins on the heating convector are not dust-clogged (photo at left). If your building is occupied by pets who shed much hair this step can be very important.
Getting good air flow through the heat exchanging fins of all finned heat exchanging devices such as heating convectors or finned copper tubing heating baseboards can make a significant difference in liberating the heat output from the device.
Just gently vacuum off the convector using a brush attachment and your vacuum cleaner - take care not to bend the fins.
A heating service contractor can provide more aggressive cleaning using special products, but on residential heating equipment that has not been exposed to some unusual problem we usually don't find it necessary.
HVAC Convector Life Expectancy
Question: What is the life span of a convector?
2016/07/08 Louis said:
What is the life span of a convector? The co-op I am in was built in 1963 and feel that after all these years the board needs to replace them. Is it possible for convectors to burn out after time or not live up to it's full potential?
It depends. If the convector includes an electric motor-operated blower fan or relays those might fail with age; but generally you're talking about a set of finned tubing across which air moves to deliver warmed or cooled air to the occupied space. My OPINION is that it would not be cost-justified to replace convector units based solely on age.
The fluid, refrigerant, or heating water, or steam depending on what convectors you actually using, varies in corrosivity and thus effect on convector life.
Refrigerant is virtually neutral - not corrosive unless the system is contaminated with other substances.
Water in a hydronic system is usually the same liquid re-used, and can be tested and managed for corrosivity by additives and treatments.
Steam condensate also needs to be managed for corrosivity by additives or treatments as is standard practice for steam heating systems.
If an individual convector fails because of mechanical damage or abuse that doesn't predict failure of the remaining units.
However if on inspection of convectors that are failing we found particular patterns of failure such as corrosion and resultant leaks on the failed units, I'd then suggest that your condo or co-op board needs to budget for a staged replacement of the units.
More scholarly research on convector unit life can be read at
Leyten, Joe L., and Stanley R. Kurvers. "Robustness of buildings and HVAC systems as a hypothetical construct explaining differences in building related health and comfort symptoms and complaint rates." Energy and Buildings 38, no. 6 (2006): 701-707.
Na, Yeon-Jeong, Eun-Ji Nam, and In-Ho Yang. "Life Cycle Cost Analysis of Air Conditioning Systems in a Perimeter Zone for a Variable Air Volume System in Office Buildings." Journal of Asian Architecture and Building Engineering 9, no. 1 (2010): 243-250.
Prek, Matjaz. "Environmental impact and life cycle assessment of heating systems." In Sustainable Building 2002 International Conference Summary Book, p. 360. 2002.
Excerpt: Life cycle assessment is defined by ISO 14000 series standards and is conducted by compiling an inventory of relevant inputs and outputs of a product system by evaluating the potential environmental impacts associated with the inputs and outputs and by interpreting the results of the inventory analysis and impact assessment phases.
Prek, Matjaz. "Environmental impact and life cycle assessment of heating and air conditioning systems, a simplified case study." Energy and Buildings 36, no. 10 (2004): 1021-1027.
Yang, Lijun. "Life cycle analysis of the residential HVAC systems in Montreal." PhD diss., Concordia University, 2005.
Continue reading at FAN CONVECTOR HEATERS - HYDRONIC COILS where we include heating output capacity tables, operating temperatures, flow rates, or select a topic from the More Reading links or topic ARTICLE INDEX shown below.
Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
Question: smells at window air conditioner
(Feb 19, 2014) Anonymous said:
I have a lg window reverse cycle airconditioner and about 3 days ago it started to smell like dirty feet. We have had high levels of humidity, heat and rain over the past week here in Newcastle Nsw. I have just discovered mold on the radiator coil thingy. I have got removed the majority of it with water/bleach solution and a dustpan brush. There is still mold there, the smell has improved slightly but would like to know how to fix it and how to prevent it from happening again. Any advice would be greatly appreciated, especially if there is a fairly cheap solution to the problem. :-)
(Mar 6, 2015) Anonymous said: I had a odor or mold inside the convector.
The apt maintenance took the fiberglass insulation out of the unit is this safe
It was smart to remove wet or mold-contaminated insulation as that material can't be cleaned. I'd have cleaned the unit and for best operating results, replaced the insulation with new clean material after the unit was cleaned. Removing the moldy insulation was safer than leaving it in place.
Question: Lars endurance EPB 110/175
(Mar 29, 2015) K Barrett said:
I have a Lars endurance EPB 110/175. I have 3 fan wall units, the 1st is hot, 2nd is hot but a bit less as expected but the 3rd when i bleed it it gets hot then once the fan is turned on it gets cold. Is the pump not working? The previous owner had repaired the coil elbows, could it be a blockage? any help would be appreciated.
KB if some of your units work and some not, then the problem is more likely at the non-operating unit. Indeed it may be air bound or you may have a control relay or valve that's not operating.
Search InspectApedia for AIR BOUND HEATING SYSTEM to see how to diagnose and correct the problem.
Question: how to add-on an electronic regulator to a convector unit in order to add a Nest or similar thermostat
(Apr 11, 2016) Erik D said:
Is it possible to attach an electronic regulator to these heaters (e.g. in order to add a nest or similar)?
Depending on the type of wall convector it is often possible to install a thermostatically-controlled valve that opens or closes to admit hot water or steam into the convector unit.
RE-posting for Eric without the link
Erik D said:
This is the one we have - The international environmental Horizontal Cabinet Series. Would that allow a controlled valve?
CXB Horizontal Cabinet Series, produced by IEC, International Environmental
Home » Products » Horizontal Series » CXB Horizontal Cabinet SeriesCXB Horizontal Cabinet Series
CXB Horizontal Cabinet Series The Horizontal Cabinet (CXB) fan coil is a slim, space-saving unit designed specifically for under-ceiling mounting. The CXB design flexibility allows the unit to be customized to meet a variety of job requirements.
Ceiling exposed units with an attractive cabinetry in seven nominal capacities ideal for many applications
Optional solid bottom panel can be provided on units with constructed rear return air ducts
Optional airflow configuration to maximize flexibility
UL, cUL, and MEA listed as well as AHRI certified
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 "Air Conditioning & Refrigeration I & II", BOCES Education, Warren Hilliard (instructor), Poughkeepsie, New York, May - July 1982, [classroom notes from air conditioning and refrigeration maintenance and repair course attended by the website author]
 Thanks to Mark Cramer, Tampa Florida, for assistance in technical review of the "Critical Defects" section and for the photograph of the deteriorating gray Owens Corning flex duct in a hot attic. Mr. Cramer is a Florida home inspector and home inspection educator.
 Thanks to Jon Bolton, an ASHI, FABI, and otherwise certified Florida home inspector who provided photos of failing Goodman gray flex duct in a hot attic.
 Thanks to Scott at SJM Inspect for suggesting this EPA document and for technical editing remarks regarding our air conditioning website,
SJM Inspection Service LLC, serves the entire state of CT, sjminspect.com 203-543-0447 or 203-877-4774
 Thanks to Joe Panimondo for technical editing, April 2011
 This website discusses these air conditioning and heat pump terms and problems: Air Conditioners: Central Air Conditioning Troubleshooting & Repair Guide: How to Inspect, Diagnose, & Repair Central Air Conditioning: Defects in A/C compressors, air handlers, duct work, and controls. We explain how to inspect & repair central air conditioning systems and for homeowners we also answer basic HVAC questions such as what are the basic air conditioning components? We provide guidance in determining air conditioning cooling capacity & energy efficiency, Troubleshooting air conditioning compressor problems, Diagnosing air conditioning air handler problems, Air conditioning condensate problems, Duct system inspections, defects, repairs, Cleaning air conditioning equipment & A/C refrigerants.
 HVAC brands discussed include but are not limited to: Lennox, American Standard, Amana, Everrest, Goodman, Frigidaire, Coleman and Gibson. Brands of related air handling equipment
include Honeywell, Aprilaire, White-Rogers, Broan. Nutone, Fantech, Venmar, Arzel, Hi-Velocity, Vanguard, Wirsbo, Weil McLain, Unico, Heat Link, A.O. Smith, Water Furnace, ClimateMaster, Geo-Excel, Command Aire, Friedrich, LG, Mitsubishi, Sanyo, Hart &
Cooley, Munchkin, Superstor Ultra, Lochinvar and Knight HVAC equipment.
 HVAC Employment: U.S. Department of Labor website describes HVAC jobs and the employment outlook for HVAC technicians.
 HVAC Education, Training Accreditation agencies: Quoting the U.S. DOL HVAC website above:: After completing the programs below, new technicians generally need between 6 months to 2 years of field experience before they are considered proficient. Three accrediting agencies have set academic standards for HVACR programs:
 HVAC Excellence. 1701 Pennsylvania Ave NW,
Washington, DC 20006 Tel: (800) 394-5268. Quoting: HVAC Excellence is a not for profit organization that has been serving the HVACR industry since 1994. It is our goal to improve competency through validation of the technical education process. By setting standards and verifying that they have been met, we inspire the industry to excel. We know that all of the challenges that face our industry are achievable by continuous improvement in the way that we prepare technicians.
 National Center for Construction Education and Research, 3600 NW 43rd Street, Bldg. G, Gainesville, FL 32606, Tel: 888.622.3720, Quoting:
NCCER is a not-for-profit education foundation created to develop industry-driven standardized craft training programs with portable credentials and help address the critical workforce shortage facing the construction industry.
 The Partnership for Air-Conditioning, Heating, and Refrigeration Accreditation, (PAHRA)
2111 Wilson Blvd., Suite 500
Arlington, VA 22201-3001
(703) 524-8800, Quoting: The Partnership for Air-Conditioning, Heating, Refrigeration Accreditation (PAHRA) is an independent, third party organization that is a partnership between heating, ventilation, air-conditioning and refrigeration (HVACR) educators and the HVACR industry that will award accreditation to programs that have met and/or exceeded industry validated standards. This programmatic accreditation program is the only one that is supported by the major industry associations.
Licensure. Heating, air-conditioning, and refrigeration mechanics and installers are required to be licensed by some States and localities. Requirements for licensure vary greatly, but all States or localities that require a license have a test that must be passed. The contents of these tests vary by State or locality, with some requiring extensive knowledge of electrical codes and others focusing more on HVACR-specific knowledge. Completion of an apprenticeship program or 2 to 5 years of experience are also common requirements.
In addition, all technicians who purchase or work with refrigerants must be certified in their proper handling. To become certified to purchase and handle refrigerants, technicians must pass a written examination specific to the type of work in which they specialize. The three possible areas of certification are: Type I—servicing small appliances; Type II—high-pressure refrigerants; and Type III—low-pressure refrigerants. Exams are administered by organizations approved by the U.S. Environmental Protection Agency, such as trade schools, unions, contractor associations, or building groups.
HVAC Training Courses, Schools: HVAC Technician Training Schools [http://technicianschool.net/hvac-technician-training-schools/], lists the following schools offering technical courses may offer specific training programs for potential careers, including HVAC technicians. Among HVAC schools that website lists are
Everest Colleges [http://www.everest.edu],
Florida Career College
7891 Pines Blvd
Hollywood, FL 33024
2299 Vauxhall Road
Union, NJ 07083
NOTE: when considering an HVAC training course or school, check the HVAC education accrediting associations listed above.
 Ratib Bakera is member of Refrigeration Service Engineers Society (RSES), an International
training organization for the HVACR industry provides educational and certification programs to HVACR professionals of all experience levels. www.rses.org provides information on the organization and its training materials. Independent testing and certification of HVAC technicians is provided by North American Technician Excellence - NATE - see www.natex.org.
NATE is supported by ASHRAE, the US EPA, and a host of other trade and professional associations.
 Singer brand HVAC equipment brand history: Singer was bought by & became the climate control unit of Dallas-based Snyder General Corp. (founded by a former Singer HVAC manager) in 1982. The name Singer was dropped in 1984. In 1984 Snyder General operations included Arcoaire, Comfortmaker, and McQuay. In 1991 Snyder General sold Arcoaire & Comfortmaker to Inter-City Products. In 1994 Snyder General was acquired by Hong Leong Group Malaysia. Snyder General is at 2001 Ross Avenue Dallas, TX 75201.
 Lennox air conditioning and heat pump owners manuals for air conditioners, air handlers, furnaces, heat pumps, indoor air quality systems, packaged units, water heaters, zone controls and other controls such as thermostats, are provided by Lennox at http://www.lennox.com/support/manuals.asp
 Air Diffusion Council, 1901 N. Roselle Road, Suite 800, Schaumburg, Illinois 60195, Tel: (847) 706-6750, Fax: (847) 706-6751 - email@example.com - www.flexibleduct.org/ - "The ADC has produced the 4th Edition of the Flexible Duct Performance & Installation Standards (a 28-page manual) for use and reference by designers, architects, engineers, contractors, installers and users for evaluating, selecting, specifying and properly installing flexible duct in heating and air conditioning systems.
Features covered in depth include: descriptions of typical styles, characteristics and requirements, testing, listing, reporting, certifying, packaging and product marking.
Guidelines for proper installation are treated and illustrated in depth, featuring connections, splices and proper support methods for flexible duct. A single and uniform method of making end connections and splices is graphically presented for both non-metallic and metallic with plain ends."
The printed manual is available in English only. Downloadable PDF is available in English and Spanish.
 Engineering toolbox properties of water - http://www.engineeringtoolbox.com/water-thermal-properties-d_162.html and email: firstname.lastname@example.org web search 09/16/2010
 Owens Corning Duct Solutions - www.owenscorning.com/ductsolutions/ - provides current HVAC ductwork and duct insulating product descriptions and a dealer locator. Owens Corning Insulating Systems, LLC, One Owens Corning Parkway, Toledo, OH 43659 1-800-GET-PINK™
 "Flexible Duct Media Fiberglas™ Insulation, Product Data Sheet", Owens Corning - see owenscorning.com/quietzone/pdfs/QZFlexible_DataSheet.pdf "Owens Corning Flexible Duct Media Insulation is a lightweight, flexible, resilient thermal and acoustical insulation made of
inorganic glass fibers bonded with a thermosetting resin."
"Air Conditioning & Refrigeration I & II", BOCES Education, Warren Hilliard (instructor), Poughkeepsie, New York, May - July 1982, [classroom notes from air conditioning and refrigeration maintenance and repair course attended by the website author]
 FlowKinetics LLC, 528 Helena Street
Bryan, Texas 77801 USA, Tel: (979) 680-0659, Email: email@example.com, Website: www.flowkinetics.com, "FKS 1DP-PBM Multi-Function Meter
Pressure, Velocity & Flow
User’s Manual", web search 07/16/2012, original source: http://www.flowkinetics.com/FKS_1DP_PBM_Manual.pdf [copy on file] and "FKT Series Flow Measurement And
Pressure Acquisition System
User's Manual" http://www.flowkinetics.com/FKTSeriesManual.pdf [copy on file]
 Histoire de l'Académie royale des sciences avec les mémoires de mathématique et de physique tirés des registres de cette Académie: 363–376. Retrieved 2009-06-19.- Pitot Tubes, Henri Pitot (1732)
 Wikipedia provided background information about some topics discussed at this website provided this citation is also found in the same article along with a " retrieved on" date. NOTE: because Wikipedia entries are fluid and can be amended in real time, we cite the retrieval date of Wikipedia citations and we do not assert that the information found there is necessarily authoritative.
"Pressure sensor", retrieved 7/16/2012
 "GE Zoneline® Owners Manual and Installation Instructions, Heat/Cool Model 2900, Heat Pump Model 3900", General Electric Corporation, [copy on file].
 "GE Zoneline® Owners Manual and Installation Instructions, Heat Pump Model 5800", General Electric Corporation, [copy on file].
 N Lu, YL Xie, Z Huang, "Air Conditioner Compressor Performance Model", U.S. Department of Energy, August 2008, [copy on file as PNNL-17796.pdf] Available to the public from the National Technical Information Service,
U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22161
ph: (800) 553-6847, fax: (703) 605-6900
online ordering: http://www.ntis.gov/ordering.htm
 Yinger R, R Bravo, and D Martinez. 2006 Air Conditioner Stalling Effects Study/Air Conditioner Testing
Procedures. Southern California Edison, Rosemead, California
 Bravo, R, R Yinger, and L Gaillac. 2006. Conditioner Stalling Unit Level Solutions Test Report. Southern
California Edison, Rosemead, California.
 Lu N, B Yang and Z Huang. 2008a. Evaluation of Southern California Edison Air-Conditioner Stalling
Solutions. PNNL-17686, Pacific Northwest National Laboratory, Richland, Washington.
 Danny S. Parker, John R. Sherwin, Bart Hibbs, "Development of High Efficiency Air Conditioner Condenser Fans", ASHRAE Transactions June 2005, [copy on file as FSEC-CR-1674-05.pdf]
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: firstname.lastname@example.org. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
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TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop, Associates, Toronto - Carson Dunlop Weldon & Associates 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.
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.
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