Oil water heater diagnosis & repair questions & answers:

FAQs on oil-fueled water heating equipment aid in troubleshooting, adjustment, or repair of your water heater.

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.

Oil Fired Water Heater Troubleshooting FAQs

These questions & answers about oil-fired water heaters were posted originally at OIL FIRED WATER HEATERS - be sure to review that article.

Our photo illustrates a pair of water heaters including an oil fired water heater that has leaked water onto the basement floor.

[Click to enlarge any image]

On 2020-11-23 - by (mod) -

Therese

Watch out: DO NOT keep pushing that reset button - the risk is ultimately a puffback explosion of unburned oil. Instead you need a service tech who will look for a dirty nozzle or oil burner electrodes that need cleaning and adjustment, or other operating problems like an oil delivery blockage, clogged oil filter, etc.

On 2020-11-23 by Therese Bishop

I have a oil fired hot water heater. It has started to kick off. Pressing the reset works for less than a minute then kicks back off. Have tightened the wires and replaced the nozzle. What might be the problem?

On 2020-07-20 - by (mod) -

Vickie

Thank you for a very helpful question, can a leak in an oil burner oil supply line cause loss of domestic hot water?

The answer is definitely. A leak in an oil line not only leaks oil out but at least are in when the oil burner is running. That air leak into the oil line can cause the oil burner to malfunction, running poorly, unevenly, Smokey, sweetie. In turn those conditions can ultimately cause the oil burner to shut down on safety. If the oil burner that we're talkin about was providing heat for your domestic hot water then yeah you've now got no hot water

On 2020-07-20 by Vickie

I noticed a leak in my oil line yesterday and today I have no hot water, can that be connected? Leak is just a drip

On 2020-04-26 - by (mod) -

Sure DJ

on your oil fired water heater you will find an aquastat that has a dial or small knob that is the temperature adjustment. Usyally the aquastat has a gray cover.

See detaiks at
https://inspectapedia.com/plumbing/Hot_Water_Temperature.php

Post a photo of your heater and in a 2nd comment , of the control and I can comment further.

On 2020-04-26 by DJ

I need to adjust the temperature of our oil hot water heater. Can you provide me with the instructions and advice as the water is very hot. Than you

On 2020-04-13 - by (mod) -

Joe

Summary of which way to turn the oil safety valve to turn oil flow OFF

It's opposite of a conventional water valve.

Turning the knob counter-clockwise (which would be opening a water valve) is "closing" the OSV or oil safety valve. You will see that turning the OSV knob counter-clockwise (from right to left if looking down on the valve) loosens it and allows the spring-loaded valve shaft to move "down" into the valve body, closing the valve.

See details at OIL LINE SAFETY VALVE TURN DIRECTION to OPEN or SHUT inspectapedia.com/heat/Oil_Safety_Valve_Turn.php

In my photo below the OSV is in the OPEN position - the telltale is that the screw is visible protruding up through the top of the silver-gray valve handle.

On 2020-04-13 by Joe DeMaio

Which direction do you turn the shut off valve to shut off the oil flow?

On 2020-04-1 - by (mod) -

You rray need to bleed air from the system

On 2020-04-10 by Mike

Oil fuel not flowing to water heater after replacing nozzle and filter and all fuel lines are opened ?

On 2020-02-17 - by (mod) - Bock model 51ppc heater is not working,

Angel,

The Bock 51PPC water heater (shown here ) - used as a water heater - has itself nothing to do with heating a home, but it's possible that to service the heater a tech turned off oil supply to your heating system - or of course there's an independent problem. Give the service company a call and let me know what is found as that will assist others.

On 2020-02-17 by Angel

Our bock model 51ppc heater is not wirking, we have hot water but no heat to the house. And it just got service

On 2020-02-16 - by (mod) -

Laura the blockage can be due to debris at the water heater hot line exit connection or at a valve shutting off cold-in or hot out of the heater.

Try flushing the water heater to see if there's a lot of debris; that'd be a clue.

Watch out: be sure the heater is OFF and cool before flushing and that it's fully re-filled before turning it back on.

Flush procedure details are in the ARTICLE INDEX on this page.

On 2020-02-16 5 by Laura

My water heater is heating and the dip tube is good but water is not exiting the water heater and going to house? Any suggestions?

On 2019-05-19 - by (mod) - temperature sensor well leaks

Bob

I think you mean that the sensor well into which the aquastat's temperature probe is inserted is leaking.

Yes you will need to

- cool off the boiler

- drain the boiler pressure and drain water level to below the sensor well

- remove and replace the well, using a suitable sealant - before installing the new sensor well (they're readily available at plumbing suppliers) clean the threads on the boiler.

Also for older larger diameter wells with smaller probes you probably need to use thermal-conductive paste or grease in the sensor well.

On 2019-05-05 by bob

aquastat is working but is leaking water may be the well ? is this common? its 150.00 to replace parts non refundable ? also i cant loosen the nut ! but will try a bigger wrench . should i just replace the h.w.h. or do you think the the parts will stop the leak ? the tank is in good shape. do to cost i was going to change it to elec. now is a reverse fired oil. 2700.00. thanks bob

On 2019-01-06 - by (mod) - intermittent very brief oil burner on-cycle

I struggled with this intermittent very brief oil burner on-cycle for some time at a NY system.

In addition to cleaning and tuning the sytem,

We replaced a primary control and I insisted that the aquastat temperature sensor be checked in its insertion well and that the manufacturer's recommended thermal grease be applied.

That ultimately took care of the problem.

Of course your system could have a different problem including such simple faults as a loose or corroded electrical connection or a failing transformer or a transformer that's not properly wired.

On 2019-01-05 by Donald Martin

otherwise works fine

My oil fired hot water boiler starts and runs for a second and stops, sometimes several times

On 2018-09-09 - by (mod) -

sorry I don't understand the question. Or was it a question?

On 2018-09-09 by Kenneth Heimlich

How to stop hot water for showers..replace with electric hot water heater.

On 2018-08-02 - by (mod) -

Erich

To avoid scalding burns you should not see "steam" coming from your hot water.

If the water heater is working properly you should be able to set up the thermostat right on the water heater to deliver water at the point of use at a temperature under-scalding.

See WATER HEATER TEMPERATURE CONTROLS https://inspectapedia.com/plumbing/Hot_Water_Temperature.php

So also see TABLE OF SCALDING TEMPERATURES & TIMES https://inspectapedia.com/plumbing/Scalding_Temperatures.php

On 2018-08-02 02:43:32.191402 by Erich

My oil fire water heater barely gets room temp, definitely no steam. How do I turn up the temp?

On 2018-08-02 by (mod) - How do I turn up the temperature on my water heater?

Erich

To avoid scalding burns you should not see "steam" coming from your hot water.

If the water heater is working properly you should be able to set up the thermostat right on the water heater to deliver water at the point of use at a temperature under-scalding.

See WATER HEATER TEMPERATURE TOO COLD or TOO HOT

Also see TABLE OF SCALDING TEMPERATURES & TIMES

On 2018-08-02 by Erich

My oil fire water heater barely gets room temp, definitely no steam. How do I turn up the temp?

On 2018-04-08 by (mod) - My oil water heater bumps on several times before it stays on

David

YOur guess is a reasonable one. There could be another problem such as a failing transformer, loose wire, failing cad cell sensor, but when the issue specifically followed running out of oil I suspect that air in the system may have caused sooty and potentially unsafe burner operation.

On 2018-04-08 by David

My oil water heater bumps on several times before it stays on. I ran out of oil and put some in and bled the line. Does this mean it needs to be cleaned.

On 2017-12-16 by (mod) - water heater Error light codes

BC

Error light codes are not standard across the world of heating equipment.

Take a look at the brand and model of water heater you're using, then dig out the installation and operation manual for it. The back of that document will give error and light codes.

If you don't have the manual let me know and we may have one or can help you find one.

On 2017-12-16 by b c macdonald

red light comes on when oil burner is working shuts off unit

On 2017-07-27 by (mod) - guy told me that the tank needed to be replaced, as it was "flaking" inside.

Denise,

Assuming that the silt of that you see is indeed coming from the water heater, which you may confirm by trying just running the hot water,

Then flushing the water heater tank, for which we have an article at this website, May reduce the problem for a time but it won't fix a corroded water heater tank whose inner protective coating has been lost or compromised.

The risk is that the rust leads to a perforation and you have a flood in the house. I would try draining the water heater, if for no other reason, in order to see if there was a lot of accumulated rust and silt in the tank. But most likely you need to replace it.

On 2017-07-27 by Denise

When repairing the burner about a year ago, the guy told me that the tank needed to be replaced, as it was "flaking" inside.

After seeing the price of new tanks, I just decided to wait and see what happened. There has NEVER been a problem with temperature or amount of hot water produced, but now, after draining a tub, or even a full sink, you can see silt (looks like dirt) left behind, and it's gotten worse. Can I drain the tank to fix this, or do I really need a new tank? Thank you!

On 2017-06-13 by (mod) - restoring a Bock water heater to service

Yes sounds like a blocked fuel line into the burner; did you install a new filter in the filter canister?

YOu might want to Use the on-page search box at the top or bottom of this page to see our article on BLOCKED OIL LINE for oil burners

On 2017-06-13 0 by Gary

I have a Bock water heater that I'm trying to bring back in service after sitting idle for many years. It was serviced by a local plumber before I purchased it. He is no longer here, so I can't ask him questions.

The motor runs when bleeder valve is opened to bleed, but when bleeder valve is closed the motor bogs down, suggesting an internal blockage. There is no fuel flow through the nozzle supply line. Looking for suggestions.

On 2017-03-30 by (mod) - anode is frozen in place

Yes I think so, Bruce. ON occasion heavy handedness and a bigger wrench+ a nut&bolt loosening liquid can free up a stuck anode mount - then you'd have to believe that the mounting threads in the heater top are in good shape and not leaky. I'm guessing the heater is past warranty.

Also check your water corrosivity.

On 2017-03-30 by Bruce Turner

my 32 gallon Bock hot water tank drains a rust colored water off the bottom drain and one anode rod is frozen in place. Does the mean it ... ment?

On 2017-02-22 by (mod) - About a week after having the furnace cleaned my furnace shut off.

John

Unfortunately it sounds as if someone guessed wrong about the problem cause and that more accurate diagnosis is needed. Call the service manager and - controlling your ire - ask that a more-experienced service technician be sent to properly find and repair the trouble.

You might mention that having to continually press a RESET button on an oil burner risks a dangerous PUFFBACK EXPLOSION - search InspectApedia for that term to read more.

On 2017-02-22 by Johnbeecher

I have an oil fired furnace. About a week after having the furnace cleaned my furnace shut off.

Nervous that something was wrong I called a service man. He took a look at it and assessed that it may be the pump. He suggested replacing it and several weeks later did so.

In the few weeks waiting for the new pump the furnace had to be reset several times as it shut off again. Since replacing the pump my furnace shuts down at least twice a day! I can't believe this is safe and am pissed that I didn't even need my pump replaced. Any thoughts as to the problem?

On 2017-02-01 by (mod) - start by noticing whether or not the water heater oil burner starts and runs.

I would start by noticing whether or not the water heater oil burner starts and runs.

On 2017-02-01 by eric hot water gets warm for about a minute then goes back to cold

My hot water gets warm for about a minute then goes back to cold and i have no clue what to do

On 2017-01-01 19:08:35.871857 by (mod) -

Typically the burner is going off on reset because of a bad flame - or a bad cad cell that senses the flame. I'd ask the service company to send out an experienced tech to correct the problem. Perhaps it's due to maladjustment or to a leak at the nozzle or a similar issue.

On 2017-01-01 by Jonathan

Hi great article very imformative! I have a bock oil fired water heater and every 2-3 days the reset button has to be pushed. This just started happening after it was serviced any idea why?

On 2016-12-03 by Mike

Have bock oil fired hot water not hot water runs for about a minute shuts down

On 2016-09-28 1 by (mod) -

Robert:

I would leave the oil fired heater OFF while waiting for your service technician. The risk if you keep restarting it is that incompletely-burned oil will cause an explosion. Search InspectApedia.com for OIL BURNER PUFFBACK to read details.

On 2016-09-28 by (mod) -

Re-Posting

AUTHOR:Robert (no email)
COMMENT:My oil fired hot water heater burner will only run for one minute

On 2016-08-26 by Kim

I have a oil fired water heater. I ran and out of oil. Since getting it filled and primed, i still do not have hot water. My heating system works fine throughout the home but no hot water.

We have drained the water tank and opened the t&p valve and the waterway is clear. Help! Lol. We had hot water with no problems until oil burner kicked off. Since filling it and resetting there has been no hot water since

On 2016-02-29 by (mod) - my motor is leaking oil how can i fix

Anon
Search InspectApedia for OIL LINE PIPING LEAKS to find almost all of the points at which leaks may occur and how to fix them.

Remaining after that is a close inspection of your oil burner to find just where the leak is actually occurring. Wipe the oil burner exterior very clean, then when it runs you should see where oil is appearing.

Check for leaks at piping connections, air bleeder valve, other un-connected oil line connection points closed with a plug, and also check for leaks in the nozzle line connections, nozzle line adapter connections, and last, leaks around the motor drive shaft, visible inside the oil burner at the coupling between the electric motor drive shaft and the oil burner fuel unit.

Leaks at a fitting can be repaired by tightening or re-making using a suitable pipe joint sealant rated for use on oil piping. If leaks are at the oil burner drive shaft you will need to replace the fuel unit entirely.

On 2016-02-26 by Anonymous

my motor is leaking oil how can i fix

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

Reply:

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.

Is this possibly water leaking into the burner cavity? - Shaun 5/4/12

Reply:

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 ?
i have oil system and a new water tank installed 4 months ago. - Fady 11/13/12

Reply:

Fady,

Make sure power is on to the heater; check and try any reset buttons. Then see the article link at the ARTICLE INDEX the bottom of this article or top titled

OIL BURNER INSPECTION AND REPAIR or the HOT WATER PROBLEM DIAGNOSIS articles found near the top of this page for the beginning of diagnostic procedures.

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

Reply:

Sean,

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.

More stuff to check includes

- a slipping coupling driving the fuel unit - the fuel unit drive shaft is connected through the blower fan over to the electric motor shaft

- a failing fuel unit

- a dirty fuel unit internal filter screen

- a dirty oil filter cartridge

- water in the fuel

Question: hot water is brown

(Jan 29, 2014) Anonymous said:

color of hot water recently somewhat brownish..

Reply:

Dunno, Anan. Depending on the materials used you could be seeing rust, bacteria, sediment from the waer source; If water has not been run for weeks or more and piping is galvanized iron, we often see rust in the first draw of water but that will clear up quickly.

If your stained water is persistent and you are served by a private well, I would have the water tested; discuss your observations with the lab as they can then suggest specific tests that may be diagnostic.

Question: oil-fired water heater shuts of about every 2 weeks

28 Oct 2014 Anonymous said:

Our oil-fired water heater shuts of about every 2 weeks , All I do is press the reset button (hold for 6 seconds) and it works for a few weeks before shutting off again. No other apparent problems..

.the water heats up quite quickly and to a good temperature. We do have to drain of the scale buildup quite often though. Any idea? Do these burners need any regular or cleaning?

28 Oct 2014 Anonymous said:

Oil fired hot water heater, hot water at first, than cools down. Noticed single faucet in bathroom turned on cold, water comes out hot.

31 Oct 2014 Paul G said:

Our oil-fired water heater shuts of about every 2 weeks , All I do is press the reset button (hold for 6 seconds) and it works for a few weeks before shutting off again. No other apparent problems...the water heats up quite quickly and to a good temperature. We do have to drain of the scale buildup quite often though. Any idea? Do these burners need any regular or cleaning?

Reply:

Paul G

Absolute: any oil fired heater needs annual service that includes cleaning, replacement of oil filter, oil fuel unit screen, nozzle, then burner adjustment, and typically vacuuming of the sooty interior of the heater and a complete check of the flue for soot - that may also need cleaning.

Sounds as if you are past due for service.

...

...

Continue reading at OIL FIRED WATER HEATERS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• OIL BURNER INSPECTION & REPAIR
• OIL BURNER WONT RUN
• OIL FIRED WATER HEATERS
• WATER HEATERS - home
• WATER HEATER PROBLEM DIAGNOSIS

Suggested citation for this web page

OIL FIRED WATER HEATER FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to PLUMBING SYSTEMS

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