Most homes in the United States have central heating systems, basically composed of:
- a burner for converting gas or oil to heat, or a resistance coil for converting electrical energy to heat
- a heat exchanger for transferring the heat to the air or water. The heat exchanger can be a furnace, when used to produce warm air, or a boiler, when used to produce hot water or steam. However, many people have been unknowingly calling a boiler a furnace, so the term furnace has become the generic name for the heat exchanger.
- a distribution system consisting of ducts or pipes for conveying the warm air, hot water or steam to the various parts of the house
- heat outlets – registers (vents) or radiators – for transferring heat into the room
- automatic safety and temperature controls
Central heating systems provide heat to the rooms throughout a house, and sometimes to a garage, an unfinished basement or other non-habitable areas. Generally, the system can also be extended to provide heat to additions or modifications to the house such as a finished attic, but whether or not the heating system can be extended depends on its heating capacity and the configuration if the distribution system. To extend the heating system of the house, a professional should be consulted to determine its feasibility.
A central heating system also has the advantage that the distribution system can be designed so to divide the house into separate heating areas. A multi-zoned house is more economical and more efficient to heat, and zoning is also used to maintain the same or different temperatures in various parts of the house. Zone control is automatic – each zone has a thermostat control that opens and closes valves for hot water and steam systems or dampers for a warm air system. If you have just one heating zone in your house, but would like to convert it to a multi-zone system, it is advisable that you have a professional check the conversion plans.
One of the most common problems with a central heating systems is distributing the heat evenly to all parts of the house – the larger the house, the more difficult it is to distribute heat evenly. The registers or radiators farthest from the furnace or boiler often do not supply as much heat as those that are closest. Balancing the heat system requires the use of dampers for warm air systems, throttling valves for hot water systems, and certain types of air valves for steam systems.
Heating Inspection Safety Guide
A heating inspection is essential, but safety precautions must be taken as there are several risks involved. The inspector is not required to operate equipment when weather conditions or other circumstances may damage the equipment, or if the inspector determines that it may cause any sort of unsafe condition. A central heating systems inspection may pose the following risks:
- air filter shock hazards
- backpressure or flashback
- blocked heating flues
Confirm Heat Operation After the Central Heating Systems Inspection
Whether to avoid a potential dispute regarding the cause of heat loss in a building, or only for your peace of mind, it is always best to confirm if the system was up and running. At the end of the inspection procedure, simply observe and note that the system was running normally. If the inspection procedure includes any action that may temporarily shut off the system (testing a shutoff switch, for instance), confirming heat operation is even more important.
Shutting Down Heating Systems
If you notice any conditions that seem unsafe, such as evidence of fire, smoke, safety controls such as relief valves, temperature limits or flue gas spillage sensors which have been moved or modified, or if the equipment has been red-tagged by a service technician, turn off all heating equipment immediately.
Do NOT Turn On Heating Systems If:
Avoid turning on heating equipment if you notice any condition that seems unsafe, such as possible open piping, unsafe wiring, leaks, fire risks, unsafe chimney or other equipment with has been “shut down”. Examine gauges for unusual pressure or temperature conditions and do not turn on, or turn off if already operating, any heating system whose temperature or pressure gauge shows abnormally high operating values. Do not operate equipment that is not vented properly and shut down any equipment if you notice an apparently blocked flue while operating it. Do not turn on any heating system that is not safely connected to a chimney.