Oil water heater diagnosis & repair questions & answers:

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

Page top photo: in addition to sooting and burn marks telling us that this water heater is not working properly and may be unsafe, the external insulating jacket is not necessary, is not recommended by the manufacturer, and, of course, will cover the water heater's data tag that you might be seeking to identify its brand, model, and age. Notice too the missing extension tube from the pressure relief valve.

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.

Photo: A Bock oil fired water heater.

The "spring loaded" valve on the side of my water heater tank won't stop spilling water

The valve on the side of the tank won't shut off seems that it is spring loaded. On 2021-01-13 by Lance

by (mod) - safety warning

Watch out: If that is a pressure temperature / pressure relief valve (TPR Valve) that is spilling water then it may be that the system is unsafe with temperature too high or pressure too high.

If that's what we're discussing STOP trying to force-close or block that valve or the water tank could explode.

You may need to turn off the water into the water heater and turn off the water heater itself.

Another possibility is that the valve itself is damaged and leaking putting could have lost its internal washer. With the water heater turned off in pressure drained first thing attacked by do is replace the valve.

Also check your building's water pressure level and the heater's temperature setting.

See detailed diagnosis and repair help at RELIEF VALVES - TP VALVES - home

 

Our Bock 51PPC Heater isn't working: we have hot water but no heat in our house

Our Bock model 51ppc heater is not working, we have hot water but no heat to the house. And it just got serviced. On 2020-02-17 by Angel

Reply by (mod) -

Angel,

The Bock 51PPC water heater (shown above) is normally used as a water heater and so would have 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 and forgot to turn it back on. Or of course there's an independent problem.

Give the service company a call, ask for an emergency "NO HEAT" call, and let me know what is found as that will assist others.

Or if you want to see if there's something obvious you can fix like a switch that's turned off, see our diagnostic and repair advice that starts

at NO HEAT - BOILER

 

My oil fired water heater goes off & I have to keep pressing the reset button: it runs for less than a minute

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 2020-11-23 by Therese Bishop

Reply 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.

Why is my Bock oil fired water heater popping the reset button every few days?

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 2017-01-01 by Jonathan

Reply 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.

Our oil fired water heater shuts down every 2 weeks - it runs for a while if I press the reset button

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? On 2014-10-31 by Paul G

Reply by (mod) -

Paul G

Absolutely, yes, oil burners need regular service.

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 way past due for service.

 

My oil fired water heater won't work when it's freezing outside

When it is below freezing outside my oil water heater quits and won't start until air outside is above the freezing mark.
Oil flow is good.

Reply by (mod) -

That's puzzling, George; what might be freezing up?

If your oil storage tank is outdoors there's the common problem of waxing or of water in the tank freezing in the tank or line or filter.

See the help we offer

at HEATING OIL CLOUD WAX GEL POINT

I'd also check the oil filter canister for signs of crud and rust and water. On 2021-02-04 by GeorgeBaxter

Can I install an oil fired water heater in a clothes closet?

Can I put a oil fired on-demand water heater in a clothes closet? On 2015-08-25 by steve

Reply by (mod) -

No.

Putting an oil fired heater in a clothes closet is risking setting the building on fire; there are fire clearance issues, working space issues, combustion air supply issues, and fire code concerns with a n oiul fired heater of any sort installed into a closet or in a bedroom.

After my water pressure tank was replaced my oil hot water heater only gives a little bit of hot water

I just had a water pressure tank replaced. Now my oil hot water heater is not working right.

There was a lot of sandy black water that came through the lines when we ran out the air in the lines. But when you run the hot water it will come out hot for about a min or so then go warm for a while then cold.

The cold dose the same running hot for a bit then to cold. If you shut them off and wait about 1 to 2 min.

This happens all over again with the hot but not the cold.

I have flushed out the heater and all the lines, but it still dose it. What could this be?

Nothing was done to the hot water tank just replaced the pressure tank for out well water. On 2015-07-03 by Cindy

Reply by (mod) -

Cindy:

Check first that the oil fired water heater is in fact on and runs in response to a call for hot water.

You may need to ask your plumber to drain debris and silt from the heater tank bottom and to check that the water heater dip tube is intact.

Typically when warm water comes out of the cold faucet then turns cold I think that the hot and cold piping are either close together in their routing (cold picks up heat from the hot pipe) or they both reside in a ceiling or other warm area near heating equipment.

So it may be that both cold and hot pipes are picking up a little heat from a boiler room but no hot water is actually being delivered by the water heater tank.

My oil fired water heater runs out of hot water too soon

The burner and hydrostat seem to be working fine. but for some reason after about 15 minutes i run out of hot water?

This has just start over the past month or so. Someone suggested the tubing inside the take might be bad, but no way to check this with out cuting the connection and pulling the tubes On 2015-01-01 by JOE

Reply by (mod) -

Joe

If you are talking about a tankless coil on a heating boiler, clogged tankless coil tubing will slow the flow rate through the tankless coil and might reduce heat transfer into the water, but it would not cause you to run out of hot water.

In fact since it would make you use hot water more slowly, it would last longer rather than run out sooner.

If the aquastat is not properly set on either a heating boiler or a water heater that could be the trouble.

Check out the advice we give

at TANKLESS COIL HOT WATER INCREASE

My oil burner's oil line leaks and now I have NO hot water: could that be the cause?

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 2020-07-20 by Vickie

Reply 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.

To understand this in more detail

see OIL SUPPLY LINE PIPING LEAKS

How do I fix oil leaks at my water heater's oil burner?

my motor is leaking oil how can i fix it? On 2016-02-26 by Anonymous

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.

Also see OIL SUPPLY LINE PIPING LEAKS

How do I adjust the tempeature of my oil fired water heater provided by an oil fired heater?

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 2020-04-26 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

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 details at WATER HEATER TEMPERATURE ADJUSTMENT CONTROLS - home

Post a photo of your heater and of the control and I can comment in more detail.

How do I turn up the temperature on my water heater?

My oil fired water heater barely gets room temp, definitely no steam.

How do I turn up the temp? On 2018-08-02 by Erich

Reply 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 TOO COLD or TOO HOT

Also see TABLE OF SCALDING TEMPERATURES & TIMES

Which way do I turn the valve to shut off oil to my water heater?

Which direction do you turn the shut off valve to shut off the oil flow? On 2020-04-13 by Joe DeMaio

by (mod) -

In my photo above 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.

Joe

Here's a 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 SUPPLY LINE SAFETY VALVE TURN DIRECTION to OPEN or SHUT

No hot water comes out of our oil fired water heater

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 2020-02-16 5 by Laura

Reply 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. Otherwise you could get burned.

Flush procedure details are at WATER HEATER FLUSH PROCEDURE 

Can I replace a leaky aquastat sensor well on my oil fired water heater?

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 2019-05-05 by bob

Reply by (mod) -

Bob

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

Yes your service technician 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.

Oil fired water heater's burner runs intermittently

My oil fired hot water boiler starts and runs for a second and stops, sometimes several times. On 2019-01-05 by Donald Martin

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.

See OIL BURNER STARTS but SHORT CYCLES on and off too frequently

Restoring a Bock oil fired water heater: motor bogs down

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 2017-06-13 0 by Gary

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

The anode is frozen in place on my Bock hot water tank

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 the heater is shot ? On 2017-03-30 by Bruce Turner

Reply by (mod) -

Possibly 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.

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.

 

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

...

...

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

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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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