Diagnostic questions & answers for a heating or water heater oil burner fuel unit.

This article reports common questions & answers about the oil burner fuel unit or "oil pump" used on oil-fired heating equpment suchj as the oil burner for a heating boiler, furnace, or oil-fired water heater.

This article series explains the inspection, diagnosis, & repair of oil burners used in heating appliances such as hot water boilers, steam boilers, & water heaters. We describe how to inspect, troubleshoot and repair heating systems to inform home owners, buyers, and home inspectors and students of heating service methods about common heating system defects.

The articles at this website describe how to recognize common oil-fired heating appliance operating or safety defects, and how to save money on home heating costs

Oil Burner Fuel Unit (oil pump) Diagnostic Questions & Answers

This article contains questions and answers regarding oil burner fuel units - these Q&A were posted originally at OIL BURNER FUEL UNIT - be sure to review the advice given there.

Also see OIL BURNER WONT RUN for a flowchart of diagnostic steps for an oil burner that won't start or won't keep running: what to check in what order.

On 2022-02-21 by Inspectapedia Com Moderator (mod) - How many times can I prime my pump before I damage the pump?

@Louise,

The procedure you described will not prime your oil pump and in fact is likely to cause incorrect operation of the oil burner as well as risking getting toxic heating oil in your mouth.

That's not how air is bled from an oil heat fuel piping system.

It sounds like you need help from your heating service tech to bleed air from your oil lines. That's done with a fitting on the fuel unit itself.

If you're not trained to do that I don't recommend it because repeated attempts to start the oil burner without success can lead to a puffback explosion.

On 2022-02-20 by Louise

How many times can I prime my pump before I damage the pump? And when fully opening the fuseable angle valve at the pump the top of threaded portion only goes to the top of the handle. I can blow through and get air but is this allowing enough fuel through to the pump.

On 2022-02-16 by Inspectapedia Com Moderator (mod) - pressure on a Sunstrand fuel unit is creeping up

@lee,

Sure. The pressure setting on a Sunstrand fuel unit is adjustable by a set-screw in a locking nut.

It's possible that those fittings are loose;

Ask your service tech to measure and set the output pressure to the correct level.

It's possible to add a pressure gauge + shut-off valve between gauge and oil line to permit frequent checking of oil pressure, but IMO the cost of adding that may approach that of replacing the fuel unit.

You've posted your question on the FAQs page for this topic.

Instructions for installing, adjusting, diagnosing heating oil pumps - fuel units - are provided in detail along with PDF downloads of instructions for specific models, found sdtarting at

OIL BURNER FUEL UNIT - home https://inspectapedia.com/heat/Oil_Burner_Pump.php

and at

OIL BURNER FUEL UNIT ANNUAL MAINTENANCE, SERVICE & REPAIR PROCEDURES

https://inspectapedia.com/heat/Oil_Burner_Pump.php#Service

On 2022-02-16 by lee

I have a Suntec oil pump.A2va-7116. I was told when I bought it that it was preset at 140psi. It has steadily been increasing in psi. I installed a gauge when I put the pump on last year. As of today the psi is up to 170. Can someone tell me why and is that a concern

On 2021-11-04 by Inspectapedia Com Moderator (mod) - pump seam leak can cause air in the high pressure oil line

@Tom Hogan,

If you're pretty confident that the problem is air in the oil lines, yes, a leak at a pump seam can be the problem but the most-common sources of air leaks are at inadequate flare fittings on the oil line between tank and burner, or at the intervening oil filter or fire safety valve.

On 2021-11-04 2 by Tom Hogan - sputtering Beckett oil burner

My Beckett burner runs fine for five minutes, the starts sputtering, and the flame goes out and safety trips. Air in line, when I open pump bleeder. Can the pump itself be the cause of air issue, or is definitely a problem with the feed? ( fittings, line, filter canister).

On 2021-02-18 by Anonymous

@Joe, I have the same problem. Did you figure it out yet?

On 2021-01-16 by danjoefriedman (mod) - "belt to fuel unit" is brittle?

Bob

Fuel units are an oil pump driven by an electric motor that's direct drive, so I'm confused about what worn belt you need.

Perhaps you mean a furnace blower fan drive belt?

Although your heating supplier may have belts as well made the original manufacturer, if that were my heater I would take the old belt off carefully and bring it to an auto supply store. The supply store will measure the belt length or diameter as well as its cross-section and shape. You'll find that you can almost certainly buy an exact match.

On 2021-01-16 by Bob Leonard

I have an older mobile home furnace in my garage, the belt to the fuel pump is brittle and cracked any idea where i can get one? Thank you

On 2020-11-1 by danjoefriedman (mod) - oil burner pump not delivering fuel

Joe

have you tried disconnecting the burner end of the high-pressure nozzle line to confirm that the pump is or is not actually delivering oil?

On 2020-11-18 by Joe

I have no fuel coming out of my pump going into burner I can bleed it good flow tried new pump it's a two pipe system I put plug in by pass still the same

On 2020-11-01 by danjoefriedman (mod) - air in the heating oil fuel lines

Green

Air in the fuel can of course come from a leak anywhere in the whole system, starting at the oil tank, piping, connections, filter, Fire-o-Matic valve, the fuel unit body (disassembled to clean that internal strainer, right?), particularly, that is, anywhere on the suction side of the system but even on the high pressure tubing to the burner too (less likely there)

You may not see the leak as it's mostly a suction leak; but a vacuum test on the fuel lines can indicate its presence.

On 2020-11-01 by Greenday694

I have an old Beckett burner, have replaced everything except pump. It's a single line gravity fed. Sometimes it will run fine for an entire day, week, even a month. Then it won't light. When I bleed it, I can see there is air in the fuel. Once I get a steady stream, close the bleeder, it light right up.

Then will work fine for a day to a month. I even replaced the line from the filter at the bottom of the tank, down into the basement to the burner itself. There are no leaks anywhere.?

On 2020-09-26 by Joe

I have a 550 in ground oil tank. My burnr recently started having isues cutting off. If I disconnect my inlet and outlet pipes from the feed to the underground tank and put them in a nearby bucket of oil, the system seems to run fine. Any suggestions how to get this working continuously from the underground tank pipes?

On 2020-03-01 - by (mod) - possible air leak at Sunstrand oil pump

Good questions, Jim.

There could be an air leak anywhere in the system including at the piping connections or at the Suntec fuel unit itself, such as at the removable cover that gives access to change out the fuel unit strainer. Start by tightening the four pump cover screws and checking / tightening any connections in the oil line.

Or have your service tech change out the strainer if it wasn't done at last service.

Unfortunately a homeowner cannot properly tune up an oil burner; special equipment, measurements, and training are needed. Doing it by eye doesn't work so well any more.

Also review the lift that the fuel unit has to achieve.

Also look in the oil filter canister for water, rust, or sludge that might tell us the line is getting blocked.

On 2020-03-01 by Jim

I have pulled a vacuum on my incoming fuel line with no indication of leakage. Had also applied compressed air pressure to the line and no sigh of leakage, but when bleeding the fuel line it takes nearly a gallon of pumped fuel to allow the furnace to run. It will continue to run flawlessly.

Since the furnace in in an intermittently used garage, it is not powered up during times when garage is not in use.

When attempting to restart it after several days, it often does not fire up, or fires up and then drops out due to fuel pressure loss. My question refers to whether or not it is possible for an internal problem with the pump a Suntec A2VA-7116?

I have been suspecting an incoming fuel line or filter leak, but believe I have eliminated those as a delivery problem through my pressure and vacuum tests. From the volume of air in the system, and not know the pump internal configuration I am at wits end on this thing.

On 2020-02-27 - by (mod) - Can installing the wrong nozzle affect the pump on an oil furnace?

Mike:

I don't think-so (I'll do some further research) as all you're doing is changing the flow-rate (GPH) and spray pattern - all residential nozzles will be in the range of the capacity of the fuel unit.

But there could be a more-subtle problem such as installing a nozzle well out of range of the fuel unit (oil pump) or such as damaging the nozzle adapter or tubing so as to cause an obstruction.

Perhaps you can be more specific about the damage or problem you're seeing with your fuel unit.

On 2020-02-27 by Mike

Can installing the wrong nozzle affect the pump on an oil furnace? Thank you.

On 2020-01-24 - by (mod) -

Not necessarily;

Dirt in the fuel unit, worn shaft bearing, improper re-assembly after changing the strainer; stripped threads at fittings.

Keep in mind that improper adjustment or leaks in the nozzle line piping anywhere on the outlet end of the fuel unit can also send oil into the blower base

On 2020-01-24 by Mike G

That was from me sorry

On 2020-01-24 by Anonymous

So I am assuming pump seal damage originates from a bad return line restriction ? On 2 line system, I just put a new one on there 3 days ago and have oil build up in bottom of blower intake already,, haven't pulled pump yet , how long are they warranted from factory u know, I'll run that thing back up to supply house if so

On 2020-01-24 - by (mod) - Signs of a blown oil pump (fuel unit) seal:

Great question Mike:

Signs of a blown oil pump (fuel unit) seal:

At the pump cover (removed to replace the pump strainer)

1. By visual inspection you may see oil seepage around the seams of the Suntec pump cover. Wipe off the pump carefully and check again for oil leaks after it's been running.

2. By inspection or measurement of the oil burner flame, if the pump is drawing air then the flame will be improper, stumbling, rumbling

If the seal about which you ask is at the fuel unit's drive shaft you'll learn that by

3. remove the pump and see if the shaft will rotate freely if not the pump is seizing and probably it has a failed bearing and/or seal

4. when the pump is removed, inspect the shaft area for oil leaks; don't forget to inspect inside the burner's blower assembly through which the pump is driven by a coupling, as oil may collect on and even drip out of the burner bottom

Perhaps some heating techs will chime in with other signs of oil burner pump seal leak signs.

On 2020-01-24 by Mike G.

How do u tell if the seal is blown on an Suntec 7116 pump? What r the tell tail signs

On 2020-01-23 - by (mod) -

Sounds as if you're not getting fuel.

Check
- fuel in the tank
- fuel lines open
- oil filter
- strainer screen in fuel unit
and be prepared to replace both
then
- check the oil supply line vacuum level

On 2020-01-23 by Mike G.

Oil furnace, down flow, got nice spark, new motor, pump, nossle, filter, electrodes transformer, controler, still won't fire up, 125psi for pump, bled lines, 2 lines, still won't fire up before all this was getting puff backs, got volger, any new suggestions?

On 2019-11-16 - by (mod) -

KJ

Using the on - page search box for

OIL PUMP BYPASS CONTROL

brings us INTERNAL FUEL UNIT BYPASS CONTROL

Please take a look at that information and don't hesitate to ask follow-up questions if any of that article is unclear.

On 2019-11-16 by LK

I have a new suntec a2va-7116. It was leaking a little and kept losing prime.
How do I adjust the bypass plug?

On 2019-11-09 - by (mod) -

re-posting after page code changes

Question:

2019/11/08 Gregg Ford

If the bleeder has oil flow could the pump still be bad?

Reply:

Yes Gregg;

When you open the bleeder on the fuel unit you might simply be seeing oil flow by gravity from the oil tank - that'd be true particularly if the pump is not even running.

Also even if the pump is on and you get oil (and perhaps no air) at the bleeder fitting, we don't know what pressure the pump is delivering - unless you instrument the pump output pressure or the input oil line vacuum.

Question:

2019/11/08 Gregg Ford

If the bleeder has oil flow could the pump still be bad?

Reply:

Yes Gregg;

When you open the bleeder on the fuel unit you might simply be seeing oil flow by gravity from the oil tank - that'd be true particularly if the pump is not even running.

Also even if the pump is on and you get oil (and perhaps no air) at the bleeder fitting, we don't know what pressure the pump is delivering - unless you instrument the pump output pressure or the input oil line vacuum.

On 2019-07-04 by (mod) - signs of a clogged oil line or filter

Sounds like a clogged oil line, filter, or bad fuel unit itself.

On 2019-07-04 by mike

a21a 7116 oil burnr it only builds pressure if i crimp thhe rturn line

On 2019-02-14 by Joe

2 pipe system new furnace leaking out bottom of fon housing after 2 months of no leaks

On 2017-11-25 by Rmryan

Thanks that's all a huge help. If the new pump don't work I'll just call a tech. But definitely can be many different things!!

On 2017-11-25 by (mod) -

If this is a two-line oil system in the pump should be self-priming and if it's not you are either out of oil or you have a bad pump or a closed valve or stuck check valve.

Or a bad air leak into the oil piping.

If this is a 1 line system if they take can feed by gravity to the fuel unit or oil pump then you should be able to open the air bleeder at the filter just before the fuel unit until well comes out at that point. I'm not on priming the pump would be easy.

If this is a one-line system and the pump has to lift out of the top of the oil tank then I suspect an air leak or a bad fuel unit.

But don't forget to also check first the coupling that's driving your fuel unit to make sure it's not slipping.

An on site experience service tech will always see things that you don't think to notice and mention that I don't think to ask

On 2017-11-25 by Rmryan

Tried bleeding it 20 times still got nothing coming out. That's why I got the line blown out but still the same. What more information would you need?

On 2017-11-25 by (mod) -

R

I don't know from just the information you've given but I suspect that your oil lines are filled with air.

On 2017-11-25 by Rmryan

I have changed the filters and nozzle and blew the lines out but my Beckett furnace won't bleed could this be my oil pump?

On 2017-11-24 by (mod) -

Possibly but so likely as an operating problem like a dirty nozzle, oil line air leak, oil line clog, fuel unit filter screen clog, or a combustion air problem that's causing the burner to trip off on safety reset.

The fact that the burner is getting quiet before the system trips off suggests to me a fuel delivery problem.

On 2017-11-24 by Anonymous

Thanks again for your interest, time and effort, it is very kind of you. Turned on the boiler at 15.30 to-day after it ran successfully all day yesterday. Just tripped again after 9 mins. 10 secs before the trip the burner note changed became less loud as if something switched off, after a few seconds a click and the noise reverted to previous level as if something was switched on but then after a few seconds the burner tripped. I was able to press the reset button after a few minutes and the boiler then fired. Does this fit in with a temperature probe fault?

On 2017-11-23 by (mod) -

Anon

I'd look for a problem with the temperature sensor for the boiler - such as bad thermal contact between the aquastat's temperature probe and the side or surface in the sensor well (may need to add thermal grease), and also for a loose wire.

On 2017-11-23 by Anonymous

Thanks for that, unfortunately it does not happen every time. The system may well runn for six hours without a problem and then after a longish burn trip.

On 2017-11-22 by (mod) -

Ted,

I don't know what's happening with that oil burner. It sounds as if perhaps something is overheating Dash possibly electric motor or there could be a coupling that heats up and slips between the motor and the fuel unit. But that's just speculation. We need an on-site service tech to watch the system. The interval over which you describe the problem occurrence is so short that anyone surely will be willing to wait eight or ten minutes to observe the problem.

On 2017-11-22 by ted

My Worcester boiler will run OK during the normal 2mins off 5 mins on cycle but sometimes when the burn is longer say 8 mins there is a variation of noise level and then the system locks out and the cut off light comes on. After 2 mins and being reset it fires up again. Any ideas?

Question: trouble bleeding air in oil lines

(Aug 5, 2012) roberto said:

I cant bleed the line

Reply:

Roberto check the air bleed instructions in the article above and let us know if / where you get into trouble

Question: what are the main parts of an oil pump used on an oil burner?

(Aug 5, 2012) Anonymous said:

what parts are in the fuel pump

Photo: the author [DF] is disassembling a Beckett Cleancut A2EA-6528 fuel unit (oil burner pump) for inspection.

Watch out: we do not reommend that you try disassembling a fuel unit unless you are trained to do so. Making a mistake could result in a leak, loss of heat, or worse, a building fire, injuries, or worse.

Reply:

Anon: if you check out some of our references/ citations you can dig into a fuel unit manual and see details, cross sectional drawings etc. There are plenty of parts inside.

Opening up the fuel unit side by removing the 4 bolts - a service tech job - reveals a replaceable filter screen that should be changed at annual service (though many techs ignore it). Incoming oil passes through the screen, through a pump, and at high pressure out to the oil burner.

A check valve stops oil flow when the motor stops spinning.

An internal bypass valve allows excess oil to circulate inside the pump or if that valve is closed in a 2-pipe system the excess oil flows back through the 2nd oil line to the oil tank.

The pump drive shaft is operated by a coupling that connects the pump through the oil burner blower assembly over to the electric motor that drives the whole assembly.

An eccentric gear operates the actual pump in the fuel unit, as shown in our photograph above.

Question: fuel unit cross reference on parts

(Mar 15, 2013) Tom said:

Good reading - learned a lot! I need to replace the oil burner fuel unit on a Lennox OHP31C-7 burner. Original appears to be a Sunstrand pump (from physical looks) but label is unreadable. Where wuld I find a cross reference to Suntec or something else suitable?

Reply:

Tom,

You want to replace the unit with another of the same brand and model type to be sure it'll work with your oil burner, though there may be some cross references between Sunstrand and Webster.

The critical features are the direction of rotation of the drive shaft for the fuel unit (LH rotation or RH rotation) and its capacity.

Try taking the old unit into your HVAC supplier who can probably match it with a replacement.

You could also simply take note of which way your oil burner drive motor shaft spins by watching briefly through the burner top - the shaft rotation direction is usually quoted when viewed from the connecting-end or exposed end of the drive shaft but as long as you can clearly state what you saw your supplier can be sure you're getting the correct-rotating replacement pump.

Question: oil burner won't stay lit

(Mar 24, 2013) Jason said:

My oil furnace will not stay ignited and running. It will fire up but will immediately trip the breaker due to lack of fuel.

I am able to manually prime the pump with oil, then reconnect all of the lines and fittings, start the furnace, and it will run for about one to two minutes before cutting out and tripping the saftey relay. I have not discovered another way to start the furnace with some, although minimal, success.Is this a common symptom of a failing or falled pump?

(Mar 24, 2013) Jason said:

My single-stage oil furnace will start up but does not ignite and immediately trips the relay breaker as a consequence from the absence of fuel.

I am able to manually prime the pump with fuel by pouring a couple ounces directly into the pump and into the "inlet line", next reconnect the line and fitting, start the furnace, quickly bleed the line until I have a solid stream,

and the furnace will instantly ignite the fuel and run for about one to two minutes before tripping the breaker from the absence or lack of fuel being supplied. I have about 15-20 gallons of fuel in my tank. Is this a symptom of a failing or failed pump?

Reply:

Jason,

I'm not sure what's wrong - could be a bad electric motor or wiring short - that's the sort of thing that trips a circuit breaker.

If on the other hand you mean the primary control is tripping and shutting down the burner, say for lack of solid flame, it's doing what it's supposed to.

If you only have 15-20 gallons in an oil tank it's techically empty - and is either sending air or sludge over to the oil burner.

Question: how to change from 2 line to 1 line fuel unit hookup

(Apr 2, 2014) Anonymous said:

dear sirs, i purchsed a miller mobile home oil funace (aprox 12 yrs old) with a dual line hook up,we capped of the return line for a single line useage, tuned it on for 20 sec. oil leak somwhere?, do i need to use a special plug or change something in the pump, thanks Bob

Reply:

Anon,

Watch out: When converting from 2-line to 1-line oil piping the fuel unit internal bypass must be opened or you risk dangerous pump damage and leaks.

We describe 1-line vs 2-line oil piping hookups and the internal bypass plug in the article above.

Question: Wikola burner won't keep burning

(Dec 19, 2014) Edward said:
We are visiting Germany for Christmas and have a Wikola burner.
When switching it on it does not burn continuously but only 3 secs at a time with a pause of about 20 secs.
It is cold outside (and inside) and it does not heat up as it usually has done.

Reply:

Definitely sounds like you need a service call - short cycling like that risks increased soot and risks an oil burner puffback.

Question: how to get the end cap off of the fuel unit

(Jan 30, 2015) Anonymous said:
how do i get the end cap off pump, ihave all 8 bolts removed

Reply:

Providing you've removed the connecting piping so that the cover is free to take off, tap it gently on one side. Be sure you've a catch-pan below as oil will spill out.

Question: Install a 3450 rpm fuel pump on a 1725 motor? Weil-Mclain 65 Series Oil boiler with a Weil-McLain burner Unit Model 45 CU-1

(Feb 22, 2015) Konrad said:
We have an older Weil-Mclain 65 Series Oil boiler with a Weil-McLain burner Unit Model 45 CU-1 (obsolete). It has a 1725 RPM motor and not sure what make oil pump (unit). Lately, I have noticed that after running for awhile, it sounds as if the oil pump is making an intermittent bearing failure type noise.

I will replace the pump at the earliest opportunity (this is in my second home, a 3.0 hour drive). My question is, can I install a 3450 RPM oil pump to run with a 1725 RPM motor, or MUST the two RPM's coincide. Thank you!

Reply:

They need to coincide. If you are keeping the boiler but want to upgrade the burner assembly it may make more sense and be more economical to buy a complete assembly. Even then there will be other details to get right: the gun and burner tube specs, the nozzle spray pattern has to match the combustion chamber design, &c.

Question: to what height can an oil burner pump lift oil?

(Apr 13, 2015) Anonymous said:

I just bought a used oil furnace and tank to put in my garage. It is a single line beckett setup. Hooked it up and temporarily put fuel line in a jug of diesel fuel about same height as pump and it works great.

Ran line thru wall out to tank which is 4 1/2 ft lower and added filter in line. Put 5 gallons in tank and tried running furnace but it keeps pulling air bubbles in fuel when I bleed. Furnace will only run 10 seconds then shuts off due to air. Tank too low? Not enough fuel in tank? Would 2 line system cure problem?
Thanks, Steve

Reply:

Anon / Steve

Even a one stage single line J pump can lift the 4 1/2 feet you cite. I suspect that there is a leak in your piping. Leaks can be hard to find. Installing a vacuum gauge on the line can help. When the burner stops, watch the gauge.

Question: Suntec fuel unit oil pump blows pressure gauge

May 22, 2015) paolo said:
what will cause a suntec type ta burner pump to blow the 40 bar pressure gauge on it

Reply:

Paolo, there are several things that will blow the pressur gauge on a heating oil burner fuel system:

1. Installing the gauge on the high pressure outlets side of the fuel unit, leaving it always exposed to pressure,
2. surges in pump pressure, or
3. blockage in the internal bypass or in the oil return line of a 2-line oil piping system.
4. Or a damaged or defective gauge.
5. Or something else we've not considered.

Question: not getting fuel to the oil burner nozzle

(Nov 3, 2015) Bob Bell said:
Just installed a fuel pump (one line), and new nozzle. The problem is that now I'm not getting any fuel up to the nozzle ! Need some help! I have tried everything I can think of!

Reply:

Bob you probably fixed this by now, but if not I would start by making sure that you have bled air from the system starting right at the oil filter.

Then you can confirm that the Fuel unit is delivering oil through the high pressure line that connects the Fuel unit to the burner. If you have oil there than the problem may be our nozzle, nozzle adapter, or even (though less likely) the tubing between oil burner high pressure outlet and the nozle adapter.

Often I see a tech simply disconnect the high pressure line at the side of the oil burner nozzle assembly, directing it into a container. Then she turns on the burner to watch to see that oil is flowing (it will be flowing at 100 psi or more) out of the nozzle line tubing

If no oil is emerging we start working backwards: confirming that there no clogged strainer in the fuel unit, and that oil is entering the fuel unit.

Question: will water damage the oil burner pump (fuel unit) ?

2016/02/20 dean said:
will water damage the pump Oil Burner Fuel Units or oil pumps:

Reply:

Water in the oil supply system, typically coming from the oil tank, will ultimately damage the fuel unit by causing rust or corrosion inside the pump motor. That may not occur right away but may occur if water remains in the pump over time, such as when the system sits idle out of the heating season.

Search InspectApedia for OIL TANK WATER to see a series of articles on detecting and removing water in the oil fired heater system.

Question: intermittent shut-downof the oil burner, off on safety / reset

2016/02/24 Chris olah said:
My oil furnace runs well but once every couple days it shuts off for no aparent reason. I push the rest button and it starts right up what could be causing this to happen ?

Reply:possible causes of intermittent oil burner failure

Thanks for the interesting question, Chris. There are several possible causes of intermittent oil burner failure that I can name and probably others that your service tech can suggest but that I've not thought-of.

- An oil burner that needs cleaning and adjustment

- A loose wire

- A cad cell sensor that's loose in its mount or is failing

- Intermittent draft problems

- A fuel unit whose coupling to the drive motor through the blower fan in the oil burner may be developing a bearing or drive shaft failure or the coupling itself may be slipping

- Water or debris in the oil tank, supply lines, filter, or fuel unit screen

- A failing transformer (spark generator)

- Shorting or damaged or improperly-set electrodes or electrode insulators

- Debris-blocked turbulator at the burner tube end

Really just about any operating problem at a heating boiler or forced warm air furnace system can show up as an intermittent failure, often worsening over time.

Often an intermittent problem gets worse until it becomes a hard failure - not very convenient during the heating season, but easier to diagnose. I would prefer to find and fix the trouble rather than "shotgunning" by just starting to replace parts.

...

Continue reading at OIL BURNER FUEL UNIT - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see OIL BURNER FUEL UNIT DIAGNOSTIC FAQs-2 - more recent questions & answers about the oil burner pump

Or see these

Recommended Articles

• FUEL UNIT BRANDS & PROPERTIES
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• OIL BURNER FUEL UNIT - home
• OIL BURNER FUEL UNIT AIR BLEED PROCEDURE
• OIL BURNER FUEL UNIT ANNUAL MAINTENANCE, SERVICE & REPAIR PROCEDURES
• OIL BURNER INSPECTION & REPAIR home page for oil burner diagnosis and repair
• OIL BURNER MANUALS
• OIL BURNER WONT RUN - Diagnostic Steps - what to check in what order,

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OIL BURNER FUEL UNIT DIAGNOSTIC FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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INDEX to RELATED ARTICLES: ARTICLE INDEX to HEATING OIL, OIL BURNERS, OIL FIRED HEATERS, OIL TANKS

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