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AIR CONDITIONING & HEAT PUMP SYSTEMS
BACKDRAFTING HEATING EQUIPMENT
BACKUP HEAT for HEAT PUMPS
BANGING HEATING PIPES RADIATORS
BLOWER FAN OPERATION & TESTING
BOOKSTORE - InspectAPedia
BTU USAGE MONITORS
CARBON MONOXIDE - CO
CIRCULATOR PUMPS & RELAYS
DIAGNOSTIC GUIDES A/C / HEAT PUMP
DIAGNOSE & FIX HEATING PROBLEMS-BOILER
DIAGNOSE & FIX HEATING PROBLEMS-FURNACE
DIRECT VENTS / SIDE WALL VENTS
DRAFT REGULATORS, DAMPERS, BOOSTERS
DUCT SYSTEM & DUCT DEFECTS
ELECTRIC MOTOR DIAGNOSTIC GUIDE
FAN, AIR HANDLER BLOWER UNIT
FLOODED HEATING EQUIPMENT REPAIR
FLUE SIZE SPECIFICATIONS
GAS BURNER Flame & Noise Defects
GAS PIPING, VALVES, CONTROLS
GEOTHERMAL HEATING SYSTEMS
HEAT PUMPS, DIAGNOSIS, REPAIR
HEATING COST SAVINGS METHODS
HEATING OIL PIPING TROUBLES
HEATING OIL TANKS
HEATING SYSTEM NOISES
HEATING SYSTEM TYPES
GAS LP & NATURAL GAS SAFETY HAZARDS
MANUALS & PARTS GUIDES - HVAC
MIXING / ANTI-SCALD VALVES
MOTOR OVERLOAD RESET SWITCH
NOISE, HEATING SYSTEMS
ODORS FROM HEATING SYSTEMS
OIL FILTERS on HEATING EQUIPMENT
OIL FILL PIPE LEAKS
OIL SPILL CLEANUP / PREVENTION
PLASTIC Plexvent / Ultravent RECALL
PUFFBACKS, OIL BURNER
RELIEF VALVE LEAKS
Reset Switch - Heater Primary Control
RESET SWITCH - ELECTRIC MOTOR
Reset Switch - Stack Relays
SAFETY, HEATING INSPECTION
SAFETY RECALLS CHIMNEYS VENTS HEATERS
SOLAR HEATING SYSTEM DESIGNS
SOOT on OIL FIRED HEATING EQUIPMENT
STEAM HEATING SYSTEMS
THERMOSTATS, HEATING / COOLING
VIDEO GUIDES: Heating System Videos
WINTERIZE A BUILDING
WOOD, COAL STOVES & FIREPLACES
WOOD STOVE SAFETY
ZONE VALVES, HEATING
Cold radiator diagnosis & repair home page: this article series describes the types of all types of heating radiators: hot water, steam, cast iron, heat convectors, baseboard heat, electric heating convectors, and we explain the diagnosis and repair of no-heat or leaks or other problems with heating radiators.
For immediate diagnosis of hot water radiator problems see COLD HOT WATER BASEBOARD / RADIATOR. For immediate diagnosis of cold steam radiator or other steam radiator troubles see COLD STEAM HEAT RADIATORS.
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How to Identify and Diagnose Problems With Hot Water or Steam Radiators, Baseboards, or Convector Units
In addition to cast iron radiators using hot water or steam as a heat source, we describe two other very common hot water heat distribution methods below. Our photo above (at page top) shows a typical "one pipe system" steam cast-iron heating radiator. A single pipe delivers steam to the radiator and condensate from the cooling steam returns to the heating boiler via that same pipe.
[Click to enlarge any image]
This article series answers most questions about all types of heating systems and gives important inspection, safety, and repair advice.
Below we describe the identification and function of different types of heating output devices in hot water or steam heated buildings. First, here is a quick no-heat diagnostic guide for radiators & baseboards. Detailed diagnostics are in the articles we cite.
Is the heat on? Make sure that your room thermostat is set to a temperature higher than the temperature in the room - so that it is calling for heat.
Is the heater working? Make sure that your heating boiler is working, that is that the heating boiler turns on and off normally. A hot water heating boiler may not turn on immediately when you turn up the room thermostat: if the water temperature in the boiler is already above the aquastat's cut-in temperature the circulators will send hot water to the radiator and the boiler will turn on later when its temperature is dropped by returning water from the cooler radiators in the building.
Don't forget to check for having run out of heating fuel. If your heating system is not working properly, see NO HEAT - BOILER.
Are the radiators turned on? Make sure that the control valve at the heating radiator is "open" or "on". See RADIATOR VALVES & HEAT CONTROLS.
Are your radiators heated by hot water or steam?
The heating system troubleshooting articles listed just below address nearly all problems with hot water or steam radiators.
If you don't know what kind of heat your building uses, we explain how to figure out the answer at HEATING SYSTEM TYPES.
Hot water heating baseboard is warmed by hot water circulating through either finned copper tubing or through cast iron baseboard sections. Carson Dunlop's sketch (below left) and our photo of a heating baseboard (below-right) show a typical modern hot water heating baseboard system installation.
Heating baseboard warms the room by a combination of radiation (the hot baseboard radiates heat onto surfaces in the room) and convection (cool air enters at the baseboard bottom, is warmed, and exits at the baseboard top - see Carson Dunlop's baseboard sketch above left). Electric heating baseboard also warms by radiation and convection but the baseboard itself is heated by an electric element rather than hot water.
Sketch of a wall convector (above left) courtesy of Carson Dunlop and our photo (above right) show a traditional wall-mounted heating convector unit.
Our photo was taken in a 1920's home in 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 (left) 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.
We discuss this problem in more detail at RADIATOR BASEBOARD or CONVECTOR COVERS.
The heat source in a wall-convector may be forced hot water, gravity hot water, steam, or the unit may be heated by electricity.
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.
Electrically-heated, steam heated, or hot water heated fan convector heating units similar to what you see in our photo here but boosted by a fan that blows room air across the heater are discussed at FAN CONVECTOR HEATERS - HYDRONIC COILS. Also see RADIANT HEAT.
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.
Also see FAN CONVECTOR HEATERS - HYDRONIC COILS for additional details.
If you are wondering why a cast iron radiator is found mounted high on a building wall or even on a ceiling, the explanation may be found in the sketch (above left) from Carson Dunlop Associates.
For buildings in which hot water circulated through the heating distribution system by gravity - that is, without using the forced hot water provided by a circulator pump - the only way we could get hot water to rise into a heating radiator was to be certain that the radiator was physically located higher than the top of the heating boiler.
If you find a shelf-like cast iron radiator like the one shown in our photo (above right) where it is being admired by a red-jacketed realtor the radiator will probably located in the kitchen or pantry of an older home where it performed double duty as a plate warmer. The cast iron radiator in our photo, with its three flat shelves, was serving dual-duty as a both a heat source and as a plate warmer for plates coming out of a chilly pantry or dish closet.
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Frequently Asked Questions (FAQs) about heating radiators in buildings: inspection, troubleshooting, repairs
Questions & answers or comments about troubleshooting heating system radiators, baseboards, convectors - hot water heating systems and steam heating systems.
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Technical Reviewers & References
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