Glossary of terms

Air Elimination Vent
A device which automatically eliminates trapped air in the “closed-loop” hydronic system.

Air Expansion Tank
A tank which provides an air cushion for pressure build-up in a closed system as the water is heated. It helps to maintain the system pressure at a constant level when the system is operating. 

Aquastat
A temperature sensing device on the boiler which is used to control the water temperature being supplied to the radiant panel. The normal setting for the Eichler Home is 130 degrees F. 

Automatic Air Vent
See: Air Elimination Vent 

Boiler
An appliance used to heat hot water for radiant panel and domestic hot water heating systems. Sometimes referred to as a hot water heater, it differs dramatically from the common domestic hot water heater used to heat service water. A “low” pressure boiler is a vessel in which water is heated for the purpose of supplying heat at pressures not exceeding 160 PSI and temperatures not exceeding 250°F. 

California Title 24 Energy Requirements
California building regulations for energy design requirements for new and remodeled homes. 

Concealed Tubing Leak
A condition where a “closed-loop” radiant panel tube embedded in the concrete loses water. 90% of all Eichler Home radiant leaks are never visible and require a pressure test for detection. 

Convection
The transfer of heat from your body caused by the movement of air around you. 

Degradation
The disintegration or deterioration of the tubing metal beyond a repairable condition. 

Distribution Manifold
A device used to connect the system distribution piping to a common source. It is usually located on the return side of the system within a closet or the garage and contains valves used to change the water flow rate in the piping. Each area of the home will normally have an individual balance valve. It is by the flow rate adjustment the heat can be balanced, increased, or decreased in individual rooms. 

Domestic Water Retrofit
The replacement of the domestic hot and cold water system with a new piping system. 

Eichler Home
A contemporary styled home featuring open living areas, flat or slightly pitched roofs, and extensive glass areas. Built on a concrete slab, these homes introduced the use of hydronic radiant panel heat for the heating system. They were built using the “community” concept from 1950 – 1965 in Northern California, between San Rafael and San Jose. There are approximately 11,000 homes in these areas. 

Electrolysis
Chemical reaction resulting in the degradation of the tubing metals. 

Electronic Ignition
An intermittent device which automatically lights the pilot flame and main burner of the boiler when the system calls for heat.

Evaporation
The transfer of heat from your body caused by water drying on your skin. 

Force Warm-Air Operating Temperature
Warm air is “blown” into the living space at 110-115°F. 

Fuel Source
The medium used by the boiler to heat water or liquid. This can be natural gas, propane, oil, electricity, wood, coal or a combination of these. 

Heat, Force Warm-Air
A heating system using fans, ducts, and a furnace/heat pump. An area is heated by convection when warm air is forced and circulated into the living space. Only the air is heated by this system. 

Heat, Hydronic Radiant Panel
A radiant panel system using hot water from a boiler or other source to heat the radiant panel. The boiler distributes the heat to the panel by circulating hot water through copper, steel, plastic, or rubber tubing usually embedded in the panel. The living space is heated by radiation. 

Heat, Radiant Panel
A heating system using a panel, usually of concrete, which when heated provides warmth into the living space by absorbing heat from one source and radiating it to another source. 

Heat Transfer
The movement of heat energy by radiation, convection, or evaporation from one source to another. 

Helium Spectrographic Analysis
A leak detection process pioneered for use in the Eichler Home by Anderson Radiant Heating in 1992. Helium gas is injected into the distribution tubing at low pressure and the spectrograph “sniffs” the helium molecule. If there is a leak in the system, because of the properties of the helium molecule, the small size allows it to leak from the closed radiant system and penetrate into the home through all types of floor coverings. The results are a precise location of all the leak(s), both large and small. THIS IS THE ONLY RELIABLE LEAK DETECTION METHOD FOR THE RADIANT PANEL IN THE EICHLER HOME. Only a spectrograph with a sensitivity level of one part per billion is acceptable and 100% successful for the detection. 

Hydronic Baseboard Retrofit
The installation of a new heating system in the Eichler Home and custom home when the existing radiant panel or other heating system is no longer usable. This is the common choice for replacement in the Eichler Home due to its adaptability and compatibility with the Eichler structure. It distributes the heat into the living space through hot water baseboard enclosures installed around the inside perimeter. The heating of the space is by convection without the use of any fans. 

Indirect Water Heating
The heating of hot water with a storage tank using an internal heat exchanger to separate the system water from the house supply water. An external heating source such as a boiler is required for this extremely efficient hot water heating system. 

Insulating Properties
The ability of a material to impede the transfer of heat. 

“Lag Period”
The time between when the concrete slab (radiant panel) is warmed by the boiler water and heat is radiated into the living space. 

Operational Checklist for the Eichler Homeowner
A useful checklist for posting in the mechanical room, when followed, allows the homeowner to quickly check the safe operation condition of the boiler and radiant panel heating system. 

Pilot
A small flame which ignites the main burner when the system calls for heat. 

Pressure Reducing Valve
A safety device which supplies the boiler with reduced water pressure from the city supply. The normal pressure setting is 12 PSI. It also maintains the boiler water level should a loss of water occur in the panel. 

Pressure Relief Valve
A safety device which releases boiler and system pressure should it exceed a preset level. The normal pressure setting of these devices for the low pressure boiler is 30-45 PSI. The preset level should never exceed the operating pressure of the boiler. 

Pressure Switch
An adjustable safety device which prevents boiler operation when the system pressure falls below the preset level, usually 5 PSI. It helps prevent boiler coil and heat exchanger damage by preventing the boiler from firing during an unsafe low water pressure condition. 

Pressure/Temperature Gauge
A device which monitors water pressure and temperature of the heating system. 

Pressure Test
A hydrostatic (water) test of the concealed radiant panel used to determine the “tightness” and “leak-free” condition of the tubing. The test should always result in “no loss” of the pressure and be performed in accordance with Code approved procedures. The introduction of helium, nitrogen, oxygen, or other type of air to pressurize the system for testing is not an acceptable test and will likely result in inaccurate conclusions. 

Pump
A device used to circulate water throughout the boiler and distribution tubing. The unit can be water or oil lubricated. Proper pump sizing is essential to provide adequate heat for the home. 

Radiant Operating Temperature
The floor temperature should never exceeds 85°F. 

Radiant Panel
The mass of concrete or other material which, when heated, stores and releases radiant heat energy into the living space. All objects, people, furniture, walls, etc., are warmed by absorbing and transferring the radiated energy. All areas within the living space are evenly heated. 

Radiation
The transfer of heat by direct rays from your body to cooler objects around you. 

Relay-Transformer
The control system for the boiler which provides electrical power to the pump and gas valve when the thermostat calls for heat. 

Retrofit
The replacement of a defective and non-repairable heating or plumbing system in a home with another new system of better quality. 

Spectrographic Analysis
The use of a spectrograph to determine the location of a concealed tubing leak by “sniffing” a particular gas. 

Standing Pilot Burner
A device which always burns a small amount of fuel to maintain a flame. The flame lights the main burner when the system calls for heat. 

Thermostat
A device which senses “air or floor” temperature, controls operation of the heating source, and maintains the room temperature within the living space. Because of the effects of the heating system, the settings with hydronic radiant panel are 3-5°F lower than with forced warm-air for the same comfort level. 

Tubing Materials
The following are common examples of materials which have been and are currently used for the distribution piping: Copper, Type “L”; Armco Plastic Coated Steel; Cold Rolled or Extruded Steel; Non-Barrier Polybutylene; PEX Non-Barrier Polyethylene; PEX Cross-Linked Barrier Polyethylene; Rubber. 

Type “L” Tube
Tube An industry standard for copper tubing defined by the tube wall thickness and identified by a “blue” strip. Type “L” copper tube wall is approximately 50% greater thickness than Type “M”. 

Type “M” Tube
Tube An industry standard for copper tubing defined by the tube wall thickness and identified by a “red” stripe. 

Uniform Mechanical Code (94)
A system of procedures designed to provide consumers with complete requirements for the installation and maintenance of heating, ventilating, cooling, and refrigeration systems and used throughout the United States by local jurisdictions. 

Universal Plumbing Code (94)
A system of procedures designed to provide consumers with safe and sanitary plumbing systems and used throughout the United States by local jurisdictions. 

Wrought Copper Fittings
Plumbing fittings used to connect copper tubes. They are composed of cast copper metal. 

Zoning
The ability to individually select and control the area in the home to be heated.