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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 HOOD, GAS HEATER
DRAFT REGULATOR, DAMPER, BOOSTER
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 NOISE DIAGNOSIS
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 RELAY
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 SYSTEMS
WINTERIZE A BUILDING
WOOD-OIL COMBINATION HEATERS
WOOD STOVE OPERATION & SAFETY
ZONE VALVES, HEATING
Heating boiler defects & operating problem troubleshooting:
Here we explain how to recognize & diagnose problems with residential heating boilers, including loss of heat, heating boiler noises, leaks, odors, or smoke, and high heating costs.
We identify different types of building heating systems and outline how to diagnose and repair heating system problems.
This article series answers most questions about central hot water heating system troubleshooting, inspection, diagnosis, and repairs.
Green links show where you are. © Copyright 2015 InspectApedia.com, All Rights Reserved.
If you have no heat and need help diagnosing the cause,
The photograph at page top shows a heating boiler which is burning through it's steel outer jacket - this condition is a potential fire hazard and requires immediate inspection and repair.
There is probably a combustion gas leak at this heater. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.
If you don't know whether your heat is provided by a furnace (hot air) or boiler (hot water)
Article Series Contents:
Types of Defects and Problems with Hot Water Heating Boilers - Hydronic Heating Systems, Loss of Heat, Noises, Leaks
Complete details about all types of heating system noises, causes, cures, are found
Noises specific to an oil burner used at heating boilers or water heaters are discussed
When observing evidence of leaks on a heating boiler, keep these points in mind:
and LEAKS at BASEBOARD, CONVECTOR, RADIATOR for details.
How to Recognize & Diagnose Inadequate Combustion Air, Sooting, or Burn Marks at Oil-Fired Heating Systems
Lack of adequate combustion aircan be indicated by or can result in these heating system operating and heating system safety worries:
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 - CO and CHIMNEY INSPECTION DIAGNOSIS REPAIR
Continue reading at DIAGNOSE & FIX HEATING PROBLEMS-BOILER or select a topic from the More Reading links shown below.
Suggested citation for this web page
Green link shows where you are in this article series.
Frequently Asked Questions (FAQs)
Question: how to prevent the heat exchanger from overheating
(June 29, 2014) Anonymous said:
Since you mention Goodman I am guessing you're asking about a heating furnace, not a hot water heating boiler (which is the subject of the article above).
If the heat exchanger on a warm air heating system is overheating then the fan limit switch is not working and the system is unsafe - and needs expert diagnosis and repair.
Check first for a common mistake such as a dirty air filter and reduced air flow through the system.
Details begin at FURNACES, HEATING
Question: howling residential gas boiler
(Jan 4, 2015) Jackson said:
Start right at the boiler: if the noise is at or in the boiler I'd shut if off immediately as it may be unsafe.
If the nose is coming from piping check for a failing circulator pump motor.
At HOWLING NOISES in BUILDINGS and
also at HOWLING HVAC sounds from air conditioners, air handlers, blower fans, heat pumps, furnaces, duct systems & their motors
we include additional examples of howling sounds traced to heating or cooling equipment.
(Jan 6, 2015) Anonymous said:
Inspected the boiler again and decided to drain the water out to check how dirty it might be but it came out clear. Can't see any reason that it would howl. Put it together and howling has stopped. ?
I can only guess - which is mere arm-waving: that sometimes draining a system will move a bit of debris or dirt, changing an orifice through which water was running. I'd still be looking at circulators; also see if there's a correlation between howling at the boiler (other than you with laughter at this advice) and temperature or boiler on or off time or boiler pressure. Other howl points might be check valves, zone valves, even air bleeders or piping elbows.
Question: running water noise in heating baseboards
(Jan 8, 2015) Anonymous said:
If the water is noisy in the hot water heating piping I suspect the system has excessive air that is not being automagically bled out by air bleeders that we usually install at the boiler, at radiators, at baseboard zones.
Question: burning smells from heating boiler: suspect burn-off of oil coatings?
(Jan 15, 2015) MLizbeth said:
My plumbing/heating man first said it had just overheated (from turning it on more often to run water through baseboards during this cold snap, so water wouldn't freeze in pipes).
But he checked it out at my insistence, and replaced the switch - he said it was, after all, damaged. But there is still a smell when the boiler goes on, i.e. it gets heated up. (He also bled out air that he said was in the pipes. Could be totally unrelated.) Smell dissipates until next time boiler kicks on. This all happened literally out of nowhere. I hate to bother him yet again with more phone calls but this smell shouldn't be the norm. What do you think?
Burning smells are not normal and should be fixed, including the cause not just the damaged part. For example backpressure in a combustion chamber can overheat nearby components.
Just be sure you distinguish between left-over odors from a prior problem and new smells.
(Jan 21, 2015) MLizbeth said:
Indeed if the switch was overheating or arcing other components in the switch box may be burned; open, examine, replace. Use the email at our CONTACT link found at page top or bottom to send me some photos for further comment if you can.
(Jan 23, 2015) MLizbeth said:
The one thing he mentioned that resonated with me was that components inside are given a light coating of oil, even the electrical wires inside. That could have overheated before the (cracked) toggle switch was replaced. I also spoke with my own oil company who helped me out with information and it looks like that is the solution to the mystery.
My husband has already called him, and he'll be replacing the whole switchbox and wiring. If I can get a photo that shows anything at all I will, but as of a couple days ago, visually, it was "picture perfect" and nothing to see other than what it should be. It appears that that oil coating just heated up. Strange the littlest things that can occur (that I a layperson would never have known of prior)! I appreciate the vast repository of information you have placed here for home owners to access, to become knowledgeable about their home systems. Thank you!
Question: boiler won't ignite - thermostat troubles
Bryan Jaicks said:
Whats wrong here? is it the aquastat relay?
Bryan, check out the diagnostics at
and also check for a thermostat wiring problem at
Questions & answers or comments about diagnosing problems with residential hot water heating systems: the heating boiler
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