Guide to Heating & Cooling Electrical Power Switches
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A guide to finding and using electrical power switches for heating and cooling systems
Where do we find the emergency-off switch for heating furnaces and boilers?
What are the basic components of hot air heating systems?
Troubleshooting heating system furnace controls
How to inspect & repair hot air heating systems - Furnaces
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Here we describe the usual location and function of electrical switches that control power to all types of heating equipment. If your building has lost heat, checking that the heating equipment is actually turned "on" at all of these switches is a first step in diagnosing the problem. This website answers most questions about central heating system troubleshooting, inspection, diagnosis, and repairs. We describe how to inspect
residential heating systems to inform home owners, buyers, and home inspectors of common heating system defects.
The articles at this website describe the basic components of a home heating system,
how to find the rated heating capacity of an heating system by examining various data tags and components, how to recognize common heating system operating or safety defects, and how to save money on home heating costs.
We include product safety recall and other heating system hazards.
Because some controls are used in common on hot water heat, hot air heat, and steam boilers, readers should see these other articles: see BOILER CONTROLS & SWITCHES, and also see BOILER PARTS LIST for a detailed list of heating boiler controls, other heating system components, parts such as circulator pumps & draft regulators. If your building uses warm air heat, see FURNACE CONTROLS & SWITCHES. If your building uses steam heat see STEAM HEATING SYSTEMS.
A Guide to Finding & Using Electrical Power Switches to Turn On or Off Heaters for Furnaces & Boilers, Heat Pumps or Electric Furnaces or Air Conditioners
Electrical power switches on heating and cooling systems: where will the power switches be located, how do we know if we have turned
on power to the heating or cooling system?
Our page top photo shows a typical emergency off switch for a heating system. Our photo at left shows a fuse box that is used to accomplish the same purpose, though this older switch is more likely to be found near the entry to a basement where heating equipment is located.
Electrical switches that turn off electric power that operates any type of heating system: furnace, boiler, steam boiler, heat pump, electric heat, are required for both safety and for service.
An emergency off switch for the building heating system should be found outside of the basement or other boiler or furnace room location and accessible so that an occupant can, in an emergency, turn off heat without having to enter a possibly smoky or dangerous area.
A second electrical "off" service switch should be found on or very close to the heating equipment itself. This second service switch is used by the heating service technician.
A third electrical switch or fuse turns off power to the heating equipment service at the building electrical panel. If a circuit breaker has tripped or a fuse has blown on the heating equipment's electrical circuit, you may be able to restore heat at the electrical panel.
But for safety reasons it is important to determine why the fuse blew or the circuit breaker tripped. If you replace a fuse or re-set a circuit breaker and the fuse blows or circuit breaker trips again, do not restore electrical power to that circuit - call a service technician to diagnose and repair the problem.
How to Identify, Reset, or Adjust Heating or Air Conditioning System Controls and Switches
For details about the setting, re-setting, or function of the controls and switches commonly found on hot air heating systems
see these articles:
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Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building design, inspection, and repair, and about indoor environment testing, diagnosis, and cleanup are at the InspectAPedia Bookstore.
Domestic and Commercial Oil Burners, Charles H. Burkhardt, McGraw Hill Book Company, New York 3rd Ed 1969.
National Fuel Gas Code (Z223.1) $16.00 and National Fuel Gas Code Handbook (Z223.2) $47.00 American Gas Association (A.G.A.), 1515 Wilson Boulevard, Arlington, VA 22209 also available from National Fire Protection Association, Batterymarch Park, Quincy, MA 02269. Fundamentals of Gas Appliance Venting and Ventilation, 1985, American Gas Association Laboratories, Engineering Services Department. American Gas Association, 1515 Wilson Boulevard, Arlington, VA 22209. Catalog #XHO585. Reprinted 1989.
The Steam Book, 1984, Training and Education Department, Fluid Handling Division, ITT [probably out of print, possibly available from several home inspection supply companies] Fuel Oil and Oil Heat Magazine, October 1990, offers an update,
Principles of Steam Heating, $13.25 includes postage. Fuel oil & Oil Heat Magazine, 389 Passaic Ave., Fairfield, NJ 07004.
The Lost Art of Steam Heating, Dan Holohan, 516-579-3046 FAX
Principles of Steam Heating, Dan Holohan, technical editor of Fuel Oil and Oil Heat magazine, 389 Passaic Ave., Fairfield, NJ 07004 ($12.+1.25 postage/handling).
"Residential Hydronic (circulating hot water) Heating Systems", Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
"Warm Air Heating Systems". Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
Heating, Ventilating, and Air Conditioning Volume I, Heating Fundamentals,
Boilers, Boiler Conversions, James E. Brumbaugh, ISBN 0-672-23389-4 (v. 1) Volume II, Oil, Gas, and Coal Burners, Controls, Ducts, Piping, Valves, James E. Brumbaugh, ISBN 0-672-23390-7 (v. 2) Volume III, Radiant Heating, Water Heaters, Ventilation, Air Conditioning, Heat Pumps, Air Cleaners, James E. Brumbaugh, ISBN 0-672-23383-5 (v. 3) or ISBN 0-672-23380-0 (set) Special Sales Director, Macmillan Publishing Co., 866 Third Ave., New York, NY 10022. Macmillan Publishing Co., NY
Installation Guide for Residential Hydronic Heating Systems
Installation Guide #200, The Hydronics Institute, 35 Russo Place, Berkeley Heights, NJ 07922
The ABC's of Retention Head Oil Burners, National Association of Oil Heat Service Managers, TM 115, National Old Timers' Association of the Energy Industry, PO Box 168, Mineola, NY 11501. (Excellent tips on spotting problems on oil-fired heating equipment. Booklet.)
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