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Photograph of wall convector air conditioner being serviced Wall Convectors for Air Conditioning & Heating
Finned heating or cooling convector units

Wall convectors for heating or cooling.

This article describes wall convectors used for building air conditioning or heating. A wall convector is a wall-mounted unit that provides cool air or warm air to the building interior. The convector unit may be a horizontal unit, a vertical unit, or a smaller convector may be suspended from a ceiling.

The wall convector may be a fully self-contained independent unit or it may be connected to a building central cooling (water, refrigerant) or heating (water, steam, electricity) source.

Here we describe types of cooling and heating wall convectors and common troubleshooting steps.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Guide to Wall Convectors used for air conditioning cooling or heating

Photograph of wall convector heating and cooling systemArticle Series Contents

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 the photo.

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

Photograph of wall convector heating and cooling system

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.

Command Aire wall convector unit identification (C) InspectApedia DC

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.

A/C indoor convector unit with cover off © D Friedman at InspectApedia.com

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.

A/C indoor convector unit with cover off © D Friedman at InspectApedia.com

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.

Also

see CONDENSATE HANDLING, HVAC for more about air conditioner or heat pump condensate drainage handling.

How Do Heating Wall Convectors 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.

Heat convectors (C) Carson Dunlop Associates

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.

Heating convector unit (C) Daniel Friedman

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.

Heating convector wall recessed (C) Daniel Friedman

Our photo (above) shows a leaky heating convector that was recessed into the wall.

Below: a common leak point at hot water based heat convectors is at the air purge or air eliminator such as shown below:

Loosening the old air eliminator prior to removal (C) Daniel Friedman at InspectApedia.com

See that repair detailed at AIR ELIMINATOR / FLOAT VENT REPLACEMENT

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.

Steam convector heater (C) Daniel Friedman

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.

Steam convector heater (C) Daniel Friedman

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.

Other antique floor or wall heaters or convectors are shown

at ANTIQUE HEATERS STILL in USE
and

at AGE of HEATERS, BOILERS, FURNACES

Fan-Driven Heating Convector Units

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

Heating convector unit (C) Daniel Friedman

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?

Reply:

Louis,

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.

Research on convector unit life

Heating & Cooling Convector Manufacturers

Beacon Morris Co Wall Convector Unit cited & discussed at InspectApedia.com

 




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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Question:

Claude May 2020
my apartment built in 1962 has xpediar heat/AC horizontal convectors with no thermostat just 3 levels fan switch. I would like to install a thermostat. Do you know where I can get the wiring diagram? Can I just use the:EG zoro.com sells this Cadet ComPack SP Built - In Stat Kit

Expediar convector unit data tag (C) InspectApedia.com Claude

Moderator reply:

Correct me if I've misunderstood, but I think that if you've already got a switch that controls fan speed for your heating/AC convectors, and if that switch is a line voltage (120VAC) control, you'd simply install a 120VAC line-voltage thermostat ahead of the fan control switch, using it to interrupt power to the fan switch.

When the thermostat isn't calling for heating or cooling the fan won't run, etc.

Details are at LINE VOLTAGE THERMOSTATS https://inspectapedia.com/heat/Thermostats_Line_Voltage.php

 

On 2021-01-18 by (mod) - Are there newer, retrofit options for thermostatic controllers to replace pneumatic units

Siemens Pneumatic Receiver Controller, Input #1 DA, Input #2 RA, Input #3 Reset Control Type - at InspectApedia.comSure, Richard; stop by your local heating supplier to see what they have at hand. There are both wired and wireless controls (wired systems would be much harder to retrofit for pneumatic-controlled sysetms) that can in turn operate the individual convector.

Usually the least-costly repair is to fix problems such as leaks or stuck or failed controls in the existing pneumatic system. IMO having a mix of some pneumatic and some "other" controls on your HVAC systems will become a maintenance nightmare and may increase service costs.

However for your purposes you'll probably want to look at wireless conrols.

Johnson Controls, Siemens, Honeywell, and others still make pneumatic controllers (a bit costly compared with a conventional thermostat but perhaps less costly than retrofitting the whole system with alternative controls.)

These references may be useful both as offering some alternatives and also for putting you into contact with industry experts who can give you more detaile help than can I.

On 2021-01-17 by Richard Maiden

Hello. I am serving on the condo engineering committee for our HOA. Question.

We have a 1965 high-rise residential condo that still has a 2 pipe hvac system. The system has conditioned air from a main air handler - conditions and dehumidifies air to each residential unit. In each unit we also have a convector with a pneumatic temp controller.

Hot water in heating season and chilled water in cooling season are delivered to the residential convectors which allows additional suplemental heating or cooling.

A good many of us have 1/4 return valves to turn the water on or off in the convectors since the pneumatic controllers have mostly failed. Are there newer, retrofit options for thermostatic controllers out there that could replace these valves? Would like to get away from the pneumatics and go to a better thermostat than can control the flow of water for individual unit comfort.

On 2020-12-08 - by (mod) -

Gerald

I'll be glad to take a stab at your wall-mounted heating and air-conditioning question, but first we need some clarification.

Many convector units are simply the heating and cooling outlet for a central boiler or air conditioner system located elsewhere in the building, so the cost of such a system has to include the central equipment, the distribution piping, and then the cost of the individual HVAC convector unit(s) - that cost ranges far too widely by building size to make any sense out of an "out of the air" cost number pick.

Alternatively, you might be better served by one or a few wall-mounted split-system heat pump units that can provide both heating and cooling -

See SPLIT SYSTEM DUCTLESS AIR CONDITIONERS / HEAT PUMPS

On 2020-12-08 by Gerald.Ruscingno@shu.edu

The cost of a wall mounted air conditioner and heating system, HVAC convector

On 2020-10-06 - by (mod) -

I don't know but I suspect that people whom you approach are going to look at this and say that the cost of the tray is trivial but the labour is enormous and they figure that the customers ultimately not going to go for it so they don't want to even waste their time examining and making a bid.

On 2020-10-06 by Mike - Carrier wont talk to an individual and basically hung up on me

Carrier wont talk to an individual and basically hung up on me and lets face it, no local (chicago) repair person wants to deal with old convectors, they want to install new ones and are too busy to want to help repair something they dont know about.

That is why I am trying to find someone who can make a new tray assembly and sell to our condo building. With 200 units and 3-6 convectors per unit, it could be a big order once it is tested out. Figure it was worth a shot posting here. If not have to find a local metal worker and start from there. Thanks!

On 2020-10-06 by danjoefriedman (mod) - find someone who can make a condensate pan and attach new fans and motor

Hi Mike;

Your photos from 7/10/2020 are indeed included on the page above.

It's disappointing that you're not getting help from your local Carrier dealer. Have you tried contacting the company for advice or another referral?

Is this a commercial installation (as it sound?) If so a local residential contractor may not feel up to tackling the job.

I'd look for a commercial HVAC contractor in your country and city (not specified here).

On 2020-10-06 by Mike

Need to find someone who can make a condensate pan and attach new fans and motor. Could be very large project as whole building needs this repair and I am trying to get quotes. I posted pictures (3) of our unit on 7/10/20 as anonymous by accident.

Carrier has been no help and we are having problems finding parts like motors and the current pan are all starting to leak from age/rust etc. For labor pricing etc figure worth to have new pan installed with attached fans and motor as labor would be cheaper and they are very old (1970's). Thanks for any help or leads....

On 2020-08-31 - by (mod) -

Jason

When condensate can't drain by gravity into the drain system and where re-plumbing the drain is an onerous task, the simplest solution that might yet fit in your convector unit is to install a small condensate pump.

But I'm not sure from your photo that the pan under the cooling coil can't drain by gravity into the drain.

On 2020-08-25 by Jason

We just had a new convector unit installed in our condo and it appears that the drain pipe (see picture, the drain pipe is the open-ended copper pipe with the red adhesive on the end) which comes out of the wall is about the same level as the condensate pan that is under the coils.

Instead of lowering the drain pipe, the plumber jury-rigged the black plastic drain pan (bottom right of the picture, on the floor) by cutting a hole through the the side of it and threaded the clear condensate pan hose through the hole, and installed a block of wood to hold the black drain pan at the right "angle" to allow condensate to flow from the clear hose to the black pan and down the drain pipe.

The black drain pan was glued to the drain pipe with adhesive.

This doesn't seem like the right setup to me as the drain pan is usually an inch or two below the condensate pan, to allow gravity to flow the water from the condensate pan to the drain pan.

Shouldn't the plumber fix the drain pipe itself by lowering it down to make the black drain pan below the condensate pan, thus allowing gravity to make the water flow out properly?

On 2020-07-20 by (mod) - bugs and rodents that enter co-op through the convectors?

M

A licensed pest control operator can find the actual points of entry and close them off. They may also proposal poisoning scheme but I would be very careful about using any toxic chemical or poison in any equipment that could blow air across the poison into the occupied space.

On 2020-07-18 by M.H.

What can be done about bugs and rodents that enter co-op through the convectors?

On 2020-07-14 - by (mod) -

That does sound like a bad control or relay

On 2020-07-14 by Susan Fischer

Two pipe system for both ac ( using chilled water) and heat with separate thermostats in each room. Suddenly one convector in my condo stopped providing AC but if you switch the thermostat to heat and adjust the temperature setting cool air comes out. Is the problem the convector of thermostat?

All other convectors in my condo are working.

On 2020-07-10 by Anonymous

1970s Carrier Wall Convector AC (C) InspectApedia.com Anon



1970s Carrier Wall Convector AC (C) InspectApedia.com Anon

On 2020-07-10 by Anonymous

Opened up unit and not sure if this is the unit model number or just the fan blade. Model 42AB4R-1 27-2
Job# 1500E6060-015 02
Motor: volts 120-1-60. Amps. 1.70
Around 1970 made

1970s Carrier Wall Convector AC (C) InspectApedia.com Anon

On 2020-07-06 - by (mod) -

Glad to assist

On 2020-07-05 2 by Lauren


Awesome - thank you SO much for all that information, it helps a lot! I can't find the brand of convector, but I'll be careful about any cut to size thanks to your warnings!

On 2020-07-05 - by (mod) -

Lauren:

If you can find the brand and model of your convector we might find the user's manual to see what the manufacturer recommends.

Otherwise, if you have the old filter, either measure its dimensions or take it along to any building or HVAC supplier to match its dimensions. You'll probably find several air filters of varying ratings all of the same size. Take care not to install a too-high-filtration-rate air filter or the air flow from your unit may be blocked and the fan could overheat.

If you do not have the old air filter for your convector unit, measure the dimensions in length and width of the rack or slots into which the air filter would fit and use those to buy a replacement of the proper length, width, and thickness.

In the "worst case" of not being able to find an exact size match for your air filter there are cut-out- air filter kits that can work.

Watch out: especially with DIY cut-out air filter kits: the air filter has to be adequately supported so as not to be drawn into the fan - lest you block the fan and set it afire.

Please see details at AIR FILTERS for HVAC SYSTEMS

On 2020-07-05 by Lauren

I have an old convector unit with a removable filter on the bottom....what kind of replacement filter can I use? I can't seem to find what I'm looking for at Home Depot.....any suggestions?

On 2020-07-04 by (mod) - Cadet ComPack SP Built - In Stat Kit

Mike

Sorry for the typos in my phone-dictated message.

Post a photo of the parts involved and I'll do some research. I can't tell from what you've said so far if we can use a generic replacement control or not.

EG zoro.com sells this Cadet ComPack SP Built - In Stat Kit

Robertshaw, Cadet, Qmark, and others provide replacement thermostats - you'll need some details about what's being replaced.

On 2020-07-04 by Mike

It is built in. Unfortunately I don’t see any model number listed. It has a toggle on off switch and a dial thermostat that outs the fan to high or low speed don’t think it actually changes temperature just fan speed. Thank you for replying

On 2020-07-01 - by (mod) -

Mike

Have you got a modrl no. for the unit?

Spencer thermostat that's built into the unit or is it a separate wall thermostat? I'm guessing it's built in since the wall thermostat is pretty generic.

On 2020-07-01 by Mike

We have a 1970 hot/cold carrier convector and need to upgrade the thermostat. Is there anyone who can help? Can do work myself If get the parts or conversion to use new style thermostat. Thanks!

On 2020-05-26 - by (mod) -

Joel that sounds odd to me, too. I'd like to see photos (one per comment) of the hole from outdoors and another of the convector from inside showing what's piped to that opening.

Perhaps it's a condensate drain?

On 2020-05-26 1 by Joel S

I own a rental apartment in a 1964 building that is heated and cooled by a convector unit.

There is a small (about 1" diameter) hole in the outside wall beneath the convector and the building supervisor told me that that is needed as a vent for the convector. I've never heard of having a vent with no cover or screen against insects, etc. Is this really a required thing? Thanks.

On 2020-05-18 - by (mod) -

Anon

I'd need to see a photo to understand just which insulation we're discussing

On 2020-05-17 by Anonymous

What is that black foam-like padding that is on the convector panel and where can I buy some? My convector panel has this soft black padding but has so much mold on it. Id like to remove all that and replace

On 2020-05-15 - by (mod) - how to contact International Environmental Co.

Joe: update on buying equipment from International Environmental,

you can contact the company directly at

IEC
Main Phone: 405.605.5000

Mailing Address
5000 W. I-40 Service Road
Oklahoma City, OK 73128 USA
https://iec-okc.com/

On 2019-07-22 - by (mod) -

Anon

If the supply and return pipes to a convection heater or backwards then if there is a check valve in the system you will have no heat

On 2019-06-01 - by (mod) -

Sorry, Joe,

But no
Have you checked with your local heating supplier to see what they can get you?


In order to absolutely assure our readers that we write and report without bias we do not sell any products nor do we have any business or financial relationships that could create such conflicts of interest.

InspectAPedia is an independent publisher of building, environmental, and forensic inspection, diagnosis, and repair information for the public - we have no business nor financial connection with any manufacturer or service provider discussed at our website.

On 2019-06-01 1 by Joe Scott

HI,
I need to buy 3 convectors. Do you know who selsl International Environmental Company brand?

I need:

ONE 400 Right Drain Two Pipe Regular 1/2 Coil
ONE 400 Left Drain Two Pipe Regular 1/2 Coil
ONE 300 Right Drain Two Pipe Regular 1/2 Coil


Thanks,

Joe

On 2019-05-23 by Anonymous

What happens if the supply and return water pipes are backwards

On 2019-05-19 - by (moWEB aerosol foam coil cleaner sold at building suppleirs like Lowes cited & discussed at InspectApedia.comd) -

Anon

Any household cleaner is fine for removing mold growth on a surface that can be washed and wiped.

If you are seeing moldy dust and crud on the actual finned convector itself then a commercial HVACR coil cleaner (typically foam and possibly a very gentle brushing - avoid fin damage) may be needed.

There are commercial HVAC coil cleaner liquids sold by any heating or air conditioning supplier and at many building supply stores as well as, for small jobs, sprays like this WEB Green White Aerosol Foam Coil Cleaner

On 2019-05-08 by Anonymous

We have been noticing mold on inside and outside of convector. What is best way to clean?

On 2019-04-14 - by (mod) -

There are dense fiberglass mats that are sold as insulation for use inside of air conditioning and some heating systems, or you could look at some new equipment at Home Depot or Lowe's store to see what they're using, or you could probably find a thin fiberglass insulating panel that would work. Watch out to be absolutely sure that you are not blocking any combustion air or you could make the system unsafe or even fatal.

On 2019-04-14 by Sandy

I have a convector in an apartment using central air (water) system. Inside of the convector cover was a patch of insulation that prevented mold from growing on the convector cover with an adhesive. Years ago being young and dumb, I ripped it off.

The room is now in use again and without that patch of insulation, mold grows on the cover during the summertime. I have looked here and online and i'm still very stumped. What kind of insulation can I get for the convector cover? It is a very similar setup as the first 2-3 photos above. Anything you can recommend I would greatly appreciate, thank you!



...

Continue reading at FAN COIL & FAN CONVECTOR HEATERS & HYDRONIC COILS where we include heating output capacity tables, operating temperatures, flow rates, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see WALL CONVECTORS HVAC FAQs - questions & answers about convector units posted originally at the end of this page.

Or see these

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WALL CONVECTORS HVAC at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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