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AGE of WATER HEATERS
ALTERNATIVE HOT WATER SOURCES
ANODES & DIP TUBES on WATER HEATERS
ANTI SCALD VALVES
APPLIANCE EFFICIENCY RATINGS
AQUASTAT CONTROL Functions
BACKDRAFTING HEATING EQUIPMENT
BACKFLOW PREVENTER, HEATER WATER FEEDER
CARBON MONOXIDE - CO
CHECK VALVES, WATER SUPPLY
CLOGGED SUPPLY PIPING
CROSS CONNECTIONS, PLUMBING
DEBRIS in WATER SUPPLY, Water Heater
DRAIN a WATER HEATER TANK
ELECTRIC WATER HEATERS
FLOODED WATER HEATER REPAIR
FREEZE-PROOF A BUILDING
GALVANIC SCALE & METAL CORROSION
GAS BURNER Flame & Noise Defects
GAS FIRED WATER HEATERS
GAS PIPING, VALVES, CONTROLS
HEATING COST SAVINGS METHODS
HOT WATER SUPPLY
HOT WATER IMPROVEMENTS
HOT WATER DELIVERY SPEED UP
HOT WATER EFFICIENCY IMPROVEMENT
HOT WATER PRESSURE EXPANSION RATE
HOT WATER PRESSURE LOSS
HOT WATER PROBLEM DIAGNOSIS
HOT WATER QUANTITY IMPROVEMENT
HYDROGEN SULFIDE GAS
INDIRECT FIRED WATER HEATERS
MANUALS & PARTS GUIDES - HVAC
MIXING / ANTI-SCALD VALVES
NO HEAT - NO HOT WATER: HEATER DIAGNOSIS
NOISE, WATER HEATER
ODORS IN WATER
PIPING IN buildings, Clogs Leaks Types
RELIEF VALVE LEAKS
RELIEF VALVES - Water Heaters
SCALE REMOVAL, WATER HEATERS
SEWER GAS ODORS
SOLAR HOT WATER HEATERS
TANKLESS WATER HEATERS
THERMAL EXPANSION of HOT WATER
THERMOSTATS, WATER HEATER
TIMERS for ELECTRIC WATER HEATERS
WATER HEATER ALTERNATIVES
WATER HEATER ANODES, DIP TUBES
WATER HEATER AIR INLET
WATER HEATER DEBRIS FLUSH
WATER HEATER DRAIN PROCEDURE
WATER HEATER EFFICIENCY
WATER HEATER FLUSH PROCEDURE
WATER HEATER NOISES
WATER HEATER PROBLEM DIAGNOSIS
WATER HEATER PROPERTIES
WATER HEATER SCALE
WATER HEATER SAFETY
WATER HEATERS for HOME HEATING USE?
WATER ODORS, CAUSE CURE
WATER PIPES, Clogs Leaks Types
WATER PRESSURE TOO HIGH: DANGERS
WATER PRESSURE LOSS DIAGNOSIS & REPAIR
WATER QUANTITY IMPROVEMENT
WATER SOFTENERS & CONDITIONERS
WINTERIZE A BUILDING
This article explains how to inspect, diagnose, adjust, maintain, or repair oil-fired water heaters including the loss of hot water or inadequate hot water supply. We include normal water heater maintenance, temperature adjustment, and improvements to hot water quantity as well as reduction in hot water heating cost. We also discuss important safety features and checks on oil fired heating equipment. We also discuss how to restore a flood-damaged water heater to service.
This article series on oil hot water heat will answer most questions about oil-fired water heaters as well as many other building plumbing system inspection or defect topics. This page contains links to in-depth articles on inspecting, testing, and repairing problems residential hot water heaters of all types, including their parts, controls, and alternative sources for hot water as well as tips for improving hot water temperature, hot water pressure, and hot water quantity. Reproduction of this web page electronically at other websites is prohibited. Our photo at page top shows an oil fired hot water system with the main components easily available, and with evidence of an oil burner operating problem.
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How do we identify an oil-fired water heater?
The sketch at left shows the basic components of an oil-fired residential hot water heater and is provided courtesy of Carson Dunlop Associates. It's easy to identify an oil-fired water heater:
Watch out: sometimes an electric water heater is installed as an additional or backup hot water source, so you'll also want to see if you have other hot water heating equipment installed, such as a Tankless Coil for Hot Water. In our photo below at left an oil-fired water heater and an indirect-fired water heater are installed in tandem.
Here are a few things to check on your oil-fired water heater:
(WARNING: This is an INCOMPLE LIST and important water heater inspection topics may be omitted as we're working on this section. If you have comments, questions, suggestions, Contact Us.)
Check the pressure and temperature relief valve on your water heater: look for evidence of corrosion, leaks, improper installation, etc. A missing, modified, blocked, or leaky pressure relief valve is extremely dangerous and can lead to a catastrophic BLEVE boiling liquid vapor explosion that can cause severe damage or even fatalities at a building. See RELIEF VALVES - TP VALVES
Look for evidence of leaks in the hot water tank, or mechanical damage, or improper installation. For example most water heaters are intended to be installed in a vertical position. Installing a hot water tank horizontally or in a hole in a crawl space is likely to cause early failure of the heater, violate the manufacturer's guidelines, and may be dangerous.
In our photo at left that puddle on the floor needs investigation.
Look for the draft regulator/barometric damper. If your conventional oil fired water heater does not have its own, personal draft regulator installed, it is impossible for the heater to have been tuned for optimum performance - you may be wasting money and heating oil. See DRAFT REGULATORS, DAMPERS, BOOSTERS
Check the settings of the water heater temperature: See Temperature of Hot Water is Too Low
Look for insulation that has been improperly added to the water tank - it may be unsafe. See Insulate Hot Water Tank?
Soot blowing out of the barometric damper or flue pipe, soot and burn marks, oil leaks, stumbling, rumbling, noisy oil burners, odors, are examples of improper oil burner operation that need prompt service.
Our page top photo and our photo at left show examples of improper oil burner operation on an oil fired water heater: both systems show soot blow-out at the water heater's combustion chamber inspection port. Our photo at left also shows that the discharge tube is missing from the relief valve - a safety concern.
Often these soot marks are a symptom of excessive pressure or "back pressure" inside the combustion chamber.
This problem can be caused by an oil fired water heater that is way past due for cleaning (soot blocks the exhaust flue), by a blocked chimney, by improper draft regulator adjustment, or other defects.
Check the hot water piping and control valves connected to the water heater for leaks, support, and for proper location of shutoff valves. An improperly installed shutoff valve on a water heater can be very dangerous, risking an explosion. Usually the "hot water tank shutoff valve" is installed only on the cold water pipe coming into the water tank. There should be no shutoff valve installed on the hot water line leaving the water tank.
Check for leaks at the water heater drain valve. Most water heater manufacturers recommend that their water tank be drained periodically. This process will help remove sludge and debris or mineral deposits that may have accumulated at the bottom of the water heater tank. Removing this debris can extend the life of the hot water tank, especially where electric and gas fired water heaters are involved. But since few people remember to open and drain the tank it may be that the drain valve does not open easily, or worse, it won't close.
Check for heating oil leaks and oil piping defects: see OIL TANK PIPING & PIPING DEFECTS
If plastic water piping is installed, such as polybutylene water supply piping, it should be at least 18" from the water heater.
Vacuum relief valves are required at water heaters in some communities, to protect against collapse of the water storage tank and to prevent backup of hot water into the cold water piping should cold water pressure drop. Here is Carson Dunlop's sketch of a vacuum relief valve.
A Guide to Oil Fired Water Heater Controls & Operation
The principal controls on an oil fired water heater include the following water tank and oil burner parts and controls:
The dip tube on many water heaters functions as a sacrificial anode, as we show here. By constructing the dip tube of a metal which is more readily corroded than the steel of a steel hot water tank, the anode protects the hot water tank from early failure due to corrosion. Here Carson Dunlop's sketch shows the location of the sacrificial anode on an electric water heater.
If your water supply happens to be highly conductive or corrosive (see WATER TESTING GUIDE) then the dip tub/sacrificial anode in the water tank may indeed corrode away until it leaks (dropping the hot water temperature) or disappears entirely.
If your hot water smells like rotten eggs, you should definitely check the condition of the sacrificial anode on the hot water heater, no matter what kind of water tank you've got installed.
For details of how to inspect or replace the sacrificial anode or dip-tube on a water heater, please see Water Heater Anodes & Dip Tubes
Check the Oil-Fired Hot Water Tank Temperature and Pressure Safety Relief Valve
How to Restore a Flood-Damaged Hot Water Heater To Save Service
I am having problems restarting the water heater ever since hurricane irene slammed into New Jersey and my basement flooded. We changed the motor and oil filter, but are having problems getting oil to feed through the lines I was wondering if there were suggestions. - Antoinette
Reply: recommended inspection & repair points for flooded oil fired water heaters, heating boilers, furnaces
When an oil fired water heater has been flooded, such as by hurricane Irene that flooded the Northeastern U.S. in August 2011, there are a number of concerns that need to be addressed.
Before addressing flooded water heaters, boilers, or furnaces, if your building has been flooded, see FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP for advice about priorities of entry, diagnosis & repair of homes or other buildings after flooding from any cause.
Now to the flooded water heater: you report having taken two important post-flood steps by changing parts (motor and oil filter) but below we have listed suggestions that might help get the water heater (or a flooded heating boiler or furnace) running again and also assure its safety and forward life.
The extent of disassembly, inspection, and replacement of parts of any heating appliance (water heater, furnace, boiler) after building flooding depends on the height reached by floodwaters and perhaps also the duration of flooding. Our flood damage photo (above left) shows our client pointing to flood water markings on the heating system expansion tank - water had nearly filled the basement of this home - the heating boiler had been completely under water.
Certainly any component that was under-water or soaked needs to be inspected, and as appropriate, cleaned or replaced. On the other hand, basement flooding that did not even reach the level of the oil burner assembly may have left that component intact, but still may have entered and damaged the heating appliance combustion chamber.
We list some key post-flood inspection and repair points for water heaters, boilers, furnaces, just below.
What oil fired water heater parts are replaced after a building flood?
Chimneys & flues: In addition, a thorough inspection of the combustion chamber for damage and debris must be conducted before the equipment is returned to service. Mud, sludge, debris anywhere inside of the heating appliance (combustion chamber, heat exchanger, chimneys, flues) has to be removed and the appliance cleaned. In addition, if area flooding sent flood waters inside of chimneys or flues (don't forget the chimney base and cleanout door) those areas need to be opened, inspected, cleaned.
Combustion chamber & chamber liner: most oil fired water heaters use a masonry (fire brick) or synethetic fabric combustion chamber liner. The liner heats to very hot during oil burner operation - a condition that helps assure complete combustion of fuel oil being sprayed into the combustion chamber. Firing up a flooded oil fired heating appliance before the combustion chamber liner has been dried or replaced risks damaging that component and possibly damaging the heater itself. Ask your service technician about the condition of the combustion chamber.
Controls on heating appliances: heating appliance (water heater, boiler, furnace) safety and limit switches and controls that have been flooded, in our OPINION, should be replaced. Other electrical components such as electrical wiring may be re-usable after inspection. Electrical panels and circuit breakers that have been flooded should be replaced as even if they "look" fine, we're not confident that internal working parts have not been damaged by water, corrosion, or even silt and debris.
Heat Distribution: Ductwork: The inspection points listed above pertain to oil fired heating devices that have been exposed to flooding or sewer backups. In addition, for building heating systems, the heat distribution system may also have been flooded, damaged, or require repairs and cleaning. See FLOOD DAMAGE in DUCT WORK for examples.
Oil burner assembly: First, you said that the "motor" was replaced. If you are not sure whether just the electric motor on the oil burner was replaced or whether the whole oil burner assembly was replaced, see OIL BURNERS for an illustration of the different parts involved. If the oil burner was submerged, and if only the oil burner's driving electric motor was replaced, additional disassembly and cleaning are probably in order to be sure that the oil burner nozzle, blower assembly, and other parts are clean and working properly.
Oil filter: it makes sense to replace an oil filter cartridge after a building has been flooded; the cartridge canister is normally air tight and thus water tight. But repair steps, movement of equipment, or other events may have contaminated the canister itself or oil tank or piping, sending more debris into the canister and filter. For this reason it makes sense to not just replace the filter, but inspect and clean the canister that holds the filter.
Oil pump (fuel unit) internal filter screen: Debris, sludge, water, rust particles are often found in the bottom of the oil filter canister. If these enter the oil burner's oil pump (properly, the fuel unit), its internal filter screen may also be clogged - I'd be sure that the fuel unit has had its filter screen replaced. Debris in the fuel unit will clog its internal check valves and the oil burner nozzle too, damaging the pump and leading to improper, even unsafe oil burner operation or total loss of heat later on. Also a clogged filter screen can prevent the fuel unit from being able to pump oil from the tank - and could be mistaken for a blocked oil line.
Oil piping: if oil piping has become contaminated with sludge, it may be possible to blow the lines clear, but if not, oil line replacement will be needed. Details about unclogging a blocked heating appliance oil line are found at OIL TANK PIPING & PIPING DEFECTS
Water heater (or boiler or furnace) insulation: most heating appliances (water heaters, furnaces, boilers) include an insulated outer jacket or "skin" that helps keep heat and noise inside the device and that improve its operation. If the insulation on a flooded appliance is still wet when the appliance is turned back on you might get lucky and dry it out during the next operating cycle. Or equipment might be damaged, or the insulation might need replacement. Ask your service technician about the condition of the appliance insulating jacket.
Oil lines between an oil tank and the water heater can become blocked with sludge, silt, mud, and even water or sewage if the lines are open to the flooding environment. But normally an oil line between the oil tank and oil burner, say at a water heater, is always full of fuel oil, and sealed against oil leaks out and air leaks in to the piping system. So dirt or water from outside the system would not easily enter the piping system. Details about spotting oil or air leaks in oil piping are found at OIL LINE LEAKS and also at OIL FILTERS on HEATING EQUIPMENT. Other oil piping defects and oil line clogging are detailed at OIL TANK PIPING & PIPING DEFECTS.
Check the oil supply valves: fusible link oil piping shutoff valves should be found at the oil burner (just before the oil filter) and perhaps also at the oil storage tank. A valve at the oil tank is often used for service convenience if the oil piping exits at the tank bottom. If oil piping or the oil tank were open to floodwaters debris often collects right at the control valve. See FIRE SAFETY CONTROLS for a discussion of oil piping fire safety valves.
Green link shows where you are in this article series.
Frequently Asked Questions (FAQs) about troubleshooting & fixing oil fired hot water heaters
Question: Why is my oil filter canister leaking oil - apparently from the bottom of the unit?
I recently replaced my oil filter (I actually replaced the entire oil canister with a new oil canister that included the filter already inside of it). The burner is working properly, the flame is on,and I'm getting hot water.
Any idea why the oil canister is leaking oil (from the bottom)? - Thanks, Ed Salva
This discussion has been relocated to OIL FILTERS on HEATING EQUIPMENT
Question: how to get the heating oil line flowing after hurricane & flood damage
I am having problems restarting the water heater ever since hurricane irene slammed into New Jersey and my basement flooded. We changed the motor and oil fiter, but are having problems getting oil to feed through the lines I was wondering if there were suggestions. - Antoinette
Reply: clearing a clogged heating oil line by CO2 blasting, filter changeout, or replacement
This discussion has been relocated to OIL TANK PIPING & PIPING DEFECTS
Question: oil water heater has water leaking out of the exhaust
I have an oil water heater and at each joint of the exhaust there is a water/oil mixture leaking out of the joints. More notably when the hot water is running, it appears to be more water than oil.
Shaun that's a good guess.
If you mean water is leaking out of the flue or flue vent connector ABOVE the water heater check for a chimney leak or problem - promptly as that may be unsafe or may damage the heater.
Also at the water heater itself check the combustion chamber for signs of water leakage into that space -you'll see a water stains, uneven corrosion build-up where the leak point(s) are, or stalactites of orange and white crud. Leaks therein mean that your water heater is probably shot.
Question: no hot water, don't know why
i don't have hot water , i dont know the reason , please help ?
Make sure power is on to the heater; check and try any reset buttons. Then see the article link at Related Topics or top titled
Question: trouble re-priming the oil fired water heater
recently had to prime my water heater thought nozzle was clogged, i replaced it and it fired up but then when it cooled down and was comanded to refire it ran but did not fire. i primed again it fired and has done the same for the last week now it won't fire upon priming, has my pump just become to week to inject enough fuel or do u think it is another issue. I still get fuel when i prime it but it is really bubbly and it take along time to clear the lines of bubbles
I forgot to tell you that it rumbled upon start up for a few seconds then it cleared up thinking wasn't getting enough fuel or pressure? - Sean 12/14/12
Your note about bubbles in the fuel suggests to me that (presuming there is plenty of oil in the oil tank) you might have an air leak in the fuel line or else air was never properly purged from the oil piping system, filter canister, & fuel unit.
Questions & answers or comments about diagnosing & repairing oil fired water heaters
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Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.