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Here we discuss how to recognize & diagnose "no-heat" problems with residential heating boilers, including loss of heat, heating boiler noises, leaks, odors, or smoke, and high heating costs.

If you don't know what kind of heat your building uses, see our introduction at BOILERS, HEATING.This website answers most questions about central hot water 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 how to recognize common heating system operating or safety defects, and how to save money on home heating costs.

Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution. © Copyright 2009 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

To Diagnose a "no heat" call the Homeowner or Heating System Inspector Must Know the Equipment

If you don't know whether your heat is provided by a furnace (hot air) or boiler (hot water), or whether your fuel is oil, gas, or electric, and whether your heat is hot water, steam, or warm air, it will be helpful to first review hot water or "hydronic" heating systems at BOILER COMPONENTS & PARTS and BOILER OPERATION DETAILS which describe hot water heating systems, and also review our descriptions of furnaces and hot air heat at FURNACES, HEATING COMPONENTS

This website discusses the diagnosis and correction of "no heat" conditions for water or hydronic or hot water or radiator or baseboard hot water heating systems. If your heating system is a hot air or furnace heating system, see How to Diagnose Loss of Heat with Hot Air Furnace Systems.

Hybrid or mixed heating systems: Some heating systems combine both hot water and hot air to heat a building, such as water to air systems which use a heating boiler (oil, gas, or electric) to heat water which circulates through (and inside of) a heat exchanger (that looks like a car radiator). The heat exchanger in a water to air heating system is then placed inside of an air handler or blower compartment where a blower fan circulates building air from return ducts to a plenum where air is blown across the heat exchanger and then the warmed air is delivered to the occupied space through additional warm air ducts or radiators.

Types of Defects and Problems with Hot Water Heating Boilers - Hydronic Heating Systems, Loss of Heat, Noises, Leaks

What sort of defects should you look for when inspecting a heating system?

• Loss of heat in your building? - boiler or furnace won't operate, or system operates but heat is not produced in the living area - we outline a diagnostic procedure for "no heat" conditions just below.
• Improper Heating System Function: noises, odors, soot, unreliability, inadequate heat distribution
• Unsafe conditions on the heating system
• Missing Heating System Components: safety controls, operating aids
• Unreliable heating systems or heating systems at or near the end of their useful life
• Improper Heating System Construction/Installation
• Heating System Damage: leaks, mechanical damage
• Clues of potential other heating system defects: leaks, corrosion, stains, abnormal temperature or pressure, high heating fuel bills
• No domestic hot water for washing and bathing? This is not usually a home heating system problem, but if your hot water is made by a tankless coil and a gas or oil fired heating boiler, the problem could be with the heating boiler itself. If your water heater is not working, find your water heater type at WATER HEATERS.

How to Diagnose Loss of Heat With Oil-Fired Hot Water or Warm Air Heating Systems

If the heating boiler oil burner is not turning on at all check the causes listed on this page. We'll take you through photo-illustrated step by step things to do when you have no heat and you need to determine what's wrong. First let's review these simple "no heat" concepts .

OFF ON SAFETY: Oil or gas burner has stopped, the safety switch is "off"

The burner on your heating boiler, furnace, or water heater has shut down, and a red "reset button" has popped up on the burner primary control or on an electric motor that operates the system. This condition is called "Safety Off". Check the following five common causes of loss of heat leading to a Safety Off condition. Photos and details follow these short paragraphs.

1. Heating oil failures - out of oil in the oil tank, clogged oil filter, clogged oil nozzle, oil line has been bent, crimped, clogged, clogged oil pump strainer (fuel unit strainer), or inability of the fuel unit to pump oil (broken motor shaft, missing internal bypass plug on a two line oil tank system, an air leak in the oil inlet line, or a leaky foot valve in the oil tank causing loss of oil prime). if the oil tank is outdoors in freezing weather the oil in the tank or in an oil line may have become waxy or jelled.

2. Oil burner motor failure: the electric motor that runs the oil burner may itself have gone off on reset. Some causes of electric motor failure: one pipe oil system with the bypass plug installed in the fuel unit (oil pump) causing excessive pressure and stalling the motor; centrifugal motor switch sticking (try banging on the motor once); motor condenser burned out; motor stator or internal windings burned or shorted; motor bearing failure. Try re-starting the motor - see Reset Switch - Electric Motors

3. Oil burner ignition failure: the oil burner's ignition transformer terminals are loose; the electrodes on the burner nozzle are dirty or not set to the proper gap; the oil is contaminated and is hard to ignite; the ignition transformer has become weak or has burned out (look for tar oozing out of the ignition transformer container); the oil burner nozzle is clogged preventing oil from contacting the ignition spark arc; the ignition electrode(s) are grounded on the air tube of the burner;

4. Faulty heating system control operation: the safety sensor that checks that a good oil burner flame has been established is not working; a stack relay spring or cad cell eye may be dirty with soot; the stack temperature may be too low for the stack relay (boiler is under-fired); the oil burner has been cycling on and off to frequently (a problem with the thermostat).

5. Irregular stack temperatures: in the flue can cause oil burner draft and temperature or control problems. Downdrafts (missing chimney cap), insufficient draft due to chimney problems, or fluctuating oil burner flame may be at fault. Also see CHIMNEY INSPECTION DIAGNOSIS REPAIR.

BURNER OFF, SAFETY NOT TRIPPED: - Oil or gas burner has stopped, no safety switch is tripped

1. No electrical power: check that all of the switches that power on the oil or gas burner are in the "on" position. Check heating circuit fuses & circut breakers. We discuss this in detail just below.

2. Electric motor problem: Check that an electric motor (for the oil burner, gas burner, or blower assembly) reset switch may have tripped. See our notes above about electric motors, and see Reset Switch - Electric Motors.

-- some of this material is paraphrased from Audel.

BURNER OPERATING PROBLEMS: Oil or Gas Burner rough, noisy, smoky, smelly

The heating burner operates but not properly. See OIL BURNER NOISE SMOKE ODORS

Next let's check each cause of no heat in detail; if your system uses warm air heat instead of water or steam, review the check-items just below before going to HEATING LOSS DIAGNOSIS-FURNACES.

SAFETY WARNING: If a heating system oil burner has been deliberately "shut down" and you don't know when or by whom this step was taken, beware of turning the heating system back on without an inspection and safety check by an expert technician.

• Check the heating fuel supply: if it is a gas furnace, is the gas turned on? If your gas is from bottled or LP gas, is the tank empty? If it is an oil fired heating furnace, check the gauge on the oil tank. Are you out of oil? See OIL TANK GAUGES. If you're out of oil call your oil company and request an emergency delivery. Usually the delivery person will also need to enter the building to bleed air from the oil lines in order to get the oil burner operating again.

Once you have assured that you have heating fuel and that electrical power is turned on to the heating unit check these controls:

• Thermostat is in the "off" position or is set to a temperature that does not call for heating (or cooling) See FAN AUTO ON Thermostat Switch for details about what turns the blower fan on and off.
• Flue gas spill switch: If your heating boileris gas-fired (natural gas or "bottled" LP gas), a flue gas spillage switch may have shut the system down after sensing possibly dangerous flue gases (that can contain fatal carbon monoxide). See   Spill Switches. This switch will not normally be found on oil fired heating equipment.
  

• Is there fuel for the boiler ?: check the oil tank gauge (see OIL TANK GAUGES for tips on how to find, read,and test the oil tank gauge. If the heating boiler is fired by natural or LP gas and not oil, check that no one has shut the gas supply valves.
  
  
• Is the thermostat calling for heat? and is the temperature at the thermostat lower than the thermostat setting?
  
  
• Does the oil burner start but then shut off? Is the system "off on reset"? if so the red "reset" button will have popped up on the oil burner control (or possibly on an electric motor operating the oil burner) and the system has an operating problem and needs service. It may be possible to re-start an oil burner that has turned itself off by pressing the red reset button ONCE.
  
  If the heating boiler or furnace re-starts and runs acceptably, you can have heat while waiting for the service technician but the system still needs inspection, service, and possibly other repairs before it can operate safely and reliably. If you push the reset button and the burner does not start and keep running for five minutes or more, DO NOT try again as you may flood the system with oil and make restarting difficult and dangerous.
  
  
• Is the oil burner motor off on reset? See MOTOR OVERLOAD RESET SWITCH
  
  
• Boilers-Hydronic Heat: Is hot water water circulating?
  
  
• Check the hot water circulator: Test to see if the circulator is operating Feeling the hot water distribution piping (Watch out it should be HOT!). Feeling the piping can indicate if circulator is running or not -- a quick change in temperature means the circulator works; slow change in temperature may occur if the circulator does not work but hot water is circulating by convection.
  
  
• Check hot water baseboards: if some baseboards are hot and others cold, are they all on the same heating zone? If not, are all of the thermostats turned up? If some heating baseboards are hot and others cold and we're sure that they're on the same zone, then the system is probably air-blocked. A heating circulator pump is capable of pushing water around in the loop of heating baseboard but is often not capable of overcoming a section of baseboard that contains a large bubble of air.
  
  It's necessary to remove such air blocks. If air blocking has been recurrent a previous owner may have installed air bleeders at strategic points. The bleeder can be opened slightly and carefully, to permit air to escape. As soon as water starts coming out of an air bleeder valve it can be closed. Automatic air purge devices are available and are usually installed right at the heating boiler but sometimes additional ones are needed at higher levels in the building.
  
  
• Check hot water radiators or convectors: if some radiators or wall convectors are hot and others are cold, and provided that the individual feed valves located at each of these devices is open (turned counterclockwise) the radiator or convector may be air blocked. Usually an individual air bleed valve is located on each of these devices.
• Check the Oil Heating Equipment Safety Controls and Switches - see FIRE SAFETY CONTROLS for photos and details

How to Diagnose Soot or Noises during Heating System & Oil Burner Operation

For full details of this topic be sure to see OIL BURNER NOISE SMOKE ODORS.

• Noises during oil burner startup - a "bang" or "puffback" which blows soot into the room through the barometric damper or through other equipment openings: the oil pump may not be shutting down properly at the end of an oil burn cycle, leaking incompletely burned oil into the combustion chamber. That oil ignites at startup causing a potentially dangerous puffback. Immediate service and repair are needed.
  
  
• Soot and black marks in the living area can sometimes indicate an unsafe or poorly-functioning heating system but these marks can also be normal in some buildings depending on other conditions. Details about soot tracking are at THERMAL TRACKING.
  
  Safety warning about soot: Sooting can occur with both gas fired and oil fired systems. Soot coming from a gas fired heater is probably indicating a very dangerous condition risking carbon monoxide poisoning. If a gas fired appliance is producing soot, it should be turned off and Immediate service is needed.
  
  
• Noises during oil burner startup - a "rumbling" sound (which usually continues all during operation" or a "stumbling" sound in the combustion chamber probably indicates that the system needs inspection and cleaning very soon. Some noise is normal however, but the normal sounds tend to be more smooth and continuous.
  
  
• Noises during oil burner shut-down - a stumbling or rumbling after the oil burner motor has stopped, indicate that oil is continuing to leak into the combustion chamber and risks a dangerous puffback - see "Noises during oil burner startup" above. Immediate service is recommended.
  
  
• Noises of shrieks or grinding coming from the electric motor or oil pump on the oil burner mean that immediate service is needed - probably a bearing is failing.
  
  
• Startup problems: noises and clues of puff back: if you see flapping at the barometric damper or if you see or hear vibrations in the system, or if you see black soot on or near heating equipment the system may be unsafe and prompt service is needed
  
  
• Noises from radiators or heating baseboards: clanking pipes or sharp snapping noises may be heard as a normal consequence of expansion of metals during the heating cycle. These noises can often be eliminated or reduced by careful routing of piping and by allowing room around heating pipes for expansion, but probably not eliminated in the case of hot water baseboards.
  
  Bubbling or rumbling noises in hot water heating piping can be caused by air in the heating lines. If the amount of air becomes excessive the system may be unable to circulate hot water and extra steps to bleed unwanted air will be required.
  
  Hissing sounds such as air escaping from radiators or other piping where air bleeder valves are installed are normal but should be brief and uncommon. If you constantly hear air hissing from radiator bleed valves double check that you understand what kind of heat you have - hissing from bleeder valves on steam heat radiators as heat is coming up in the building is normal.

How to Evaluate Heating Boiler Leaks & Corrosion

For full details of this topic be sure to see BOILER LEAKS CORROSION STAINS.

When observing evidence of leaks on a heating boiler, keep these points in mind:

• Even serious leaks may never show up as "wet" spots: A boiler may be leaking but you may see no actual water: during the heating season the boiler may always be hot, causing small leaks on the boiler or on heating piping to simply evaporate. But such leaks will usually be visually very evident: look for a build-up of corrosion, green or white or other colored mineral salts, or look for rust or water stains on the equipment.
  
  
• Internal heating boiler leaks: Some critical boiler leaks may be internal and not visible by simple inspection, such as a leak inside the boiler heat exchanger which may pass water into the combustion chamber. A service technician or a skilled home inspector should be able to spot evidence of these leaks.
  
  
• Surface rust, light, superficial rusting, is generally repairable. Clean the area and fix the leak when the boiler is next serviced and monitor for any future leaks.
  
  
• Exfoliation, or thick flaking rust on any boiler but particularly on a steel heating boiler is very serious, possibly not repairable, and risks loss of the boiler as well as sudden loss of heat in the building. Examples of this problem are at TANKLESS COILS
  
  
• Leaks related to temperature or pressure: Some leaks occur only at peak operating temperature-e-g at relief valve. On some heating boilers such as some cast-iron units, leaks may occur between boiler sections when the system is cold - on these models some technicians prefer to keep a little heat in the boiler year-round to avoid this problem. Leaks between boiler sections may be repairable but if left unattended can destroy the equipment.

A Catalog of Common Heating System Leak Points - Where to Watch for Heating System Leaks

• Tankless Coil mounting plate - see rust stains below and around plate - see TANKLESS COILS
• Pipe fittings anywhere in the system, including in water supply piping to a boiler, hot water distribution piping, or at face of coil plate - mineral salts and stains may show even a small leak though no water may be visible (it evaporates quickly on hot heating system components)
• Leaks around bolt openings - suspect hidden damage
• Leaks between sections of a cast iron boiler
• Leaks at the circulating pump mounting flanges
• Leaks at the boiler temperature/pressure relief valve. This leak may be very dangerous as corrosion from water passing through the valve may prevent its safe operation in an emergency. Prompt expert inspection and repair are needed. Watch for leaks below the valve's mouth or discharge pipe (a pipe should extend from the relief valve to a few inches from the floor) or watch for corrosion at the tip of the discharge pipe. Gently feel inside the tip of this pipe to see if it's wet. DO NOT TRY TO TEST or open or operate the relief valve itself.
  Safety warning: a leaky relief valve indicates an potentially very dangerous condition; prompt service is needed.
• Leaks at air bleeder valves - at the boiler or remote where such bleeders are placed on heating piping or baseboards or radiators
• Leaks at radiator control valves or between radiator sections
• Leaks at heating baseboards, at poorly-soldered copper pipe fittings on finned copper baseboard heating systems
• Leaks due to frozen and burst piping or in extreme cases, frozen and burst heating boilers themselves. Freezing pipes produce very distinctive types of damage such as splits or separation at solder joints.

How to Recognize & Diagnose Inadequate Combustion Air for Oil-Fired Heating Systems

For full details of this topic, also see Inadequate Combustion Air

Lack of adequate combustion air can result in improper system operation, sooting, increased heating cost, damage to oil burner components (back pressure heat can destroy an ignition transformer), higher and more frequent heating service costs, loss of heat, noises, smoke, and potentially, the production of carbon monoxide or other flue or combustion gases which escape into the building - potentially dangerous

Safety warning: The sketch shown here, courtesy of Carson Dunlop, explains how dangerous furnace back-drafting can occur when there is insufficient combustion air. These conditions can not only release flue gases into the occupied space, but they are likely to cause the production of potentially fatal carbon monoxide.

We've seen heating equipment that seemed to work just fine during its adjustment because the service technician was working with the door to the furnace or boiler room open. But when she left the system and closed the furnace room door, suddenly there was insufficient combustion air.

Also see Unsafe Air Conditioning or Heating Duct Openings which describes the risks of reduced combustion air on hot air heating systems when certain return air duct defects are present, and also see CARBON MONOXIDE/DIOXIDE and CHIMNEY INSPECTION DIAGNOSIS REPAIR

A Guide to Heating Equipment Malfunctions & Their Implications

• Noises & soot buildup can lead to a potentially dangerous "puffback" which can damage the heating equipment and blow soot and smoke throughout the building.
• Leaks on hot water heating systems are never acceptable, anywhere. Leaking relief valves need immediate attention and repair (Leaking relief valve could be due to water-logged expansion tank, improper control settings (temperature too high), improper automatic water feeder operation (pressure too high), or defective valve (leaky). True, you only have to report the valve. Did you miss problems at the other components?) Corroded relief valves also need to be test by a service technician and repaired or replaced
• Relief Valves: Do not touch the heating boiler or water heater temperature or pressure relief valve - it may open and fail to shut down. A relief valve which does not work is dangerous since the system is missing an important safety device. Should an over pressure or over temperature condition develop for other reasons, the boiler could explode.
• Corrosion on heating system parts: Do not pick at corrosion as you may start a catastrophic, un-stoppable leak requiring total system shut-down. Leaks left un repaired can destroy heating equipment.
• Tankless coils for making hot water: If there is different water pressure/flow observed in the kitchen in which the hot water pressure is significantly less than cold, even before examining the building's mechanical systems you may speculate that a tankless coil installed may be installed. What other clues suggest that the local water supply may be hard in minerals and that there may be a risk of clogged piping? When the water supply is high in minerals, the hot water pipes or tankless coils clog up before cold water piping. Is a water softener installed? Is there known "hard" water--have mineral deposits clogged the coil? Are there "cleanout" plumbing fittings on the tankless coil piping? Does this suggest a history of clogging and acid-flush treatments? A clogged coil can be repaired or replaced. How severe was that rust you observed at the tankless coil mounting plate? Severe rust may mean that the boiler must be replaced.

Examples of Heating System Defects with Important Implications

• Lack of adequate combustion air can result in improper system operation, sooting, loss of heat, noises, smoke, and potentially, the production of carbon monoxide or other flue or combustion gases which escape into the building - potentially dangerous
• Leaky oil at an oil burner ignition transformer: watch for back pressure in combustion chamber--watch out for blocked heating flue or blocked chimney - these would be unsafe, or the heater may be unreliable. An unreliable heater can lead to frozen burst pipes and costly building damage. A blocked chimney could lead to a potentially fatal carbon monoxide hazard.
• Unusual interior moisture conditions, noises, smoke, or odors during heating season--watch for blocked chimney or poor flue vent connections
• Equipment recalls: Specific heating system problem brands Repco, Blueray etc.
  [Do not confuse Repco™ heating boilers, which had fire chamber and other failures, with other products (REPCO pumps, REPCO controls, REPCO water conditioners, or water treatment that carry the Repco name. Those products are distinct from REPCO heating boilers and are produced/distributed by the R.E. Prescott Company. Further, we are unaware of any remaining warranty or replacement support for failed or antiquated Repco heating boilers.]
• Blueray Heating Boilers/Furnaces Safety Recall by the US CPSC, with additional history, photos, and technical details; Blue Flame Blue Ray
• Carbon Dioxide Gas Toxicity
• Carbon Monoxide Gas Toxicity, exposure limits, building inspection for CO hazards
• Dust from HVAC? An Investigation of Indoor Dust Debris Blamed on a Heating/Cooling System Reveals Carpet Dust
• Goodman Furnace High Temperature Plastic Vent HTPV safety recall US CPSC notice
• Home Heating System Should Be Checked [for proper venting and for CO Carbon Monoxide Hazards - DJF]
• Inspection Procedures for Oil-Fired Heating Systems Detailed step by step approaches for inspecting complex systems]
• Lennox Pulse Furnace Safety Inspection/Warranty Program: Carbon Monoxide Warning
• Oil Tanks - The Oil Storage Tank Information Website: Buried or Above Ground Oil Tank Inspection, Testing, Cleanup, Abandonment of Oil Tanks
• Oil Tanks Above Ground, UL Standards, guidance for home owners, buyers, and inspectors
• Home Inspection Report Language Library: Gas Fuel Piping or Tank Faults Basic advice - home inspection report language suggestions
• Home Inspection Report Language Library: Buried Oil Tanks, Basic home buyer advice - home inspection report language suggestions
• Home Inspection Report Language Library: Defects in Oil Tank Installations, Tanks, and Heating Oil Piping
• Plastic Heating Vent Pipe & Other Heating Safety Recall Notices
• Weil McLain Model GV Gas Boiler/gas valve CPSC recall/repair

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HEATING SYSTEMS
AIR FILTERS for HVAC SYSTEMS
AIRBOUND HEAT SYSTEM REPAIRS
ANODES & DIP TUBES on WATER HEATERS
ANTI SCALD VALVES
BACKFLOW PREVENTERS
BAROMETRIC DAMPERS
BLOWER DOORS & AIR INFILTRATION
BLUERAY Recall
BOILERS, HEATING
BOILER LEAKS CORROSION STAINS
BOILER NOISE SMOKE ODORS
BOILER OPERATING PROBLEMS
BOILER OPERATION DETAILS
BOILER PARTS LIST
BOILER PRESSURE SETTINGS
CARBON MONOXIDE/DIOXIDE
CARBON MONOXIDE WARNING
CHIMNEY INSPECTION DIAGNOSIS REPAIR
CHIMNEYS & Flues - Asbestos Transite Pipe
COOL OFF HEAT Thermostat Switch
COMBUSTION AIR DEFECTS
DRAFT REGULATORS - barometric dampers
DUCT SYSTEMS
DUST FROM HVAC?
ELECTRIC HEAT
ELECTRICAL POWER SWITCH FOR HEAT
ENERGY SAVINGS in BUILDINGS
ENERGY SAVINGS PRIORITIES
ENERGY SAVINGS RETROFIT CASE STUDY
ENERGY SAVINGS RETROFIT LEAK SEALING GUIDE
ENERGY SAVINGS RETROFIT OPTIONS
FLUE VENT CONNECTORS
FREEZE-PROOF A BUILDING
FURNACES, HEATING
FURNACE CONTROLS & SWITCHES
FURNACE OPERATION DETAILS
GAS PIPING, VALVES, CONTROLS
HEAT EXCHANGER LEAKS
HEAT LOSS in BUILDINGS
HEAT LOSS DETECTION TOOLS
HEAT LOSS INDICATORS
HEAT LOSS R U & K VALUE CALCULATION
HOUSEWRAP AIR & VAPOR BARRIERS
HEATING COST SAVINGS METHODS
HEATING LOSS DIAGNOSIS-BOILERS
HEATING LOSS DIAGNOSIS-FURNACES
HEATING OIL CLOUD WAX GEL POINT
HEATING OIL EXPOSURE HAZARDS, LIMITS
HEATING OIL SLUDGE
HEATING SMALL LOADS
HEAT PUMPS
HEATING SYSTEM INSPECTION PROCEDURE
HIGH EFFICIENCY BOILERS/FURNACES
INSULATION & VENTILATION INSPECTION & IMPROVEMENT
MOTOR OVERLOAD RESET SWITCH
NO HEAT - BOILER / FURNACE DIAGNOSIS
OIL BURNER NOISE SMOKE ODORS
OIL BURNER SOOT & PUFFBACKS
OIL FUEL TYPES & CHARACTERISTICS
OIL TANKS
OIL TANK GAUGES
OIL TANK SLUDGE
OIL TANK TESTING
OIL TANKS, BURIED
PLASTIC HEATER VENT
PULSE COMBUSTION HEATERS
RADIANT HEAT
RADIANT HEAT Floor Mistakes to Avoid
RADIANT SLAB FLOORING CHOICES
RADIANT SLAB TUBING & FLUID CHOICES
RADIATORS
RELIEF VALVES - TP Valves on Boilers
Relief Valves - Water Heaters
Reset Switch - Heater Primary Control
Reset Switch - Electric Motors
Reset Switch - Stack Relays
SAFETY DURING HEATING INSPECTION
Safety Recalls
  BLUERAY Recall
  CHIMNEYS & Flues - Asbestos Transite
  Goodman HTPV RECALL
  Heat Recovery Ventilator RECALL
  Lennox Furnace Manuals
  Lennox WARNING
  Weil McLain RECALL
SPILL SWITCHES
STACK RELAY SWITCHES
STEAM HEATING SYSTEMS
COMBUSTION GASES & PARTICLE HAZARDS
COMBUSTION PRODUCTS & IAQ
DEFINITION of Heating & Cooling Terms
DRAFT HOODS - gas fired
DRAFT REGULATORS - barometric dampers
  Expansion Tanks
  Gauges on Heating Equipment
  Limit Switches, Boilers
  Low Water Cutoff Valves, Boilers
  Mixing Valves
  Pressure Switch, Steam Boiler
  Relief Valves - TP Valves
  Sight Glass, Steam Boiler
  Spill Switches
  Stack Relay Switch
  Steam Pressure Gauge
  Steam Vents
  Low Water Cutoff Controls
  Water Feeder Valves, Steam
TANKLESS COILS
THERMAL EXPANSION of MATERIALS
THERMAL MASS in BUILDINGS
THERMAL MASS in UPSTAIRS
THERMAL TRACKING & HEAT LOSS
THERMOSTATS
Transite Pipes, Chimneys & Flues

• Thanks to Alan Carson and Bob Dunlop, Carson Dunlop, Associates, Toronto, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education, publications, report writing materials, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
• R.E. Prescott Company, a producer of other REPCO™ residential and industrial products as well as a provider of design-build engineering services is at 10 Railroad Avenue, Exeter, NH 03833. Tel: 603-722-04321 or 888-786-7482. Trish O'Keefe from Prescott informed us (10/7/2009) that their company had nothing to do with the failed Repco heating boilers discussed at InspectAPedia.com. She wrote:
  • Our company manufactures & distributes residential water treatment equipment, including our Repco line of conditioners. We have a plumbing & heating supply dept as well. We are mistaken for the Repco Boiler company on a regular basis, most frequently in Oct. and Nov.
  • Any information you could give me on the other Repco company would be appreciated. We've assumed it is no longer in business, and we'd like to know that for sure. Many callers want to know where to get replacement parts and I would be glad to direct them if I knew...plus there's always a chance they might be interested in a Crown Boiler instead.

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.
• ...

More Information on Building Diagnostic Inspections and Repairs

• Carbon Monoxide Gas Toxicity, exposure limits, poisoning symptoms, and inspecting buildings for CO hazards
• Dust from HVAC? An Investigation of Indoor Dust Debris Blamed on a Heating/Cooling System Reveals Carpet Dust
• Goodman Furnace High Temperature Plastic Vent HTPV safety recall US CPSC notice
• Home Heating System Should Be Checked [for proper venting and for CO Carbon Monoxide Hazards - DJF]
• Inspection Procedures for Oil-Fired Heating Systems Detailed step by step approaches for inspecting complex systems]
• Lennox Pulse Furnace Safety Inspection/Warranty Program: Carbon Monoxide Warning
• Oil Tanks - The Oil Storage Tank Information Website: Buried or Above Ground Oil Tank Inspection, Testing, Cleanup, Abandonment of Oil Tanks
• Oil Tanks Above Ground, UL Standards, guidance for home owners, buyers, and inspectors
• Plastic Heating Vent Pipe & Other Heating Safety Recall Notices
• Weil McLain Model GV Gas Boiler/gas valve CPSC recall/repair
• 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 Steam Heating Systems", Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
• "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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