Hot Topics: Boiler Using More Oil Than Normal After Service

A technician working on a boiler.

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Original Post: Boiler seems to be using much more oil than before

davidm Member

I have an energy kinetics system 2000 boiler in my house. A few weeks ago, my oil company did its regular yearly maintenance/cleaning. Ever since, I've noticed much higher oil usage than what's normal for this time of the year, and the weather hasn't been much colder than usual (if at all).

What could possibly cause this increased oil usage? Could something have been done during the tune-up to cause this? Thanks.

heatpro Member

If it's only been a few weeks since the tune up was done, how can you be sure you're using more oil than normal? Have you noticed anything different than normal with the operation of the system, e.g., is the boiler staying hot even with no zones calling?

Bud9051 Member

Check to see if any notes were added to your service tag, like efficiency or parts replaced.

As heatpro said, it takes time to confirm fuel use and the fuel gauge on the tank isn't very accurate. Do what you can to record use and relate that to heating degree days. Your fuel provider may share those numbers with you, but they are also part of local weather information.

If you have all prior fuel use data (gallons and delivery date), pull that out. If not, request it from your fuel company for the past three years. I've used that information to create a "gallons per degree day" history.

Have you talked to the service company yet?

davidm Member

Haven't talked to the service company yet. There is a fuel gauge on the tank that has been quite accurate for years, so I have no reason to mistrust it, and it clearly shows considerable increase in usage. Other than that, I haven't really noticed anything different. The technician who serviced the boiler, oddly enough, didn't add anything to the service tag, so I don't really know what he did other than clean it.

Vermont Member

Was the oil tank full at the beginning of this test period?

The shape of most oil tanks can cause reliance on only the gauge to be a little misleading (not deceptive) at the beginning and again at the end of drawing from it because the float's descent retards as it moves from the top down into the middle where the sides are parallel. Then, its movement is accelerated as it nears the tank's bottom and the distance between the sides narrows.

Did the company's service invoice detail what was done?

Bud9051 Member

Now, the oil pros will have to correct me on this as I'm not a pro on this subject and in Maine energy auditors were forbidden from touching the heating systems, thus the training excluded everything related. But, it was my understanding that filling out the service tag and even testing the efficiency of the unit was a required part of service. My experience up here has been mixed from nothing to a computer generated test slip. That service tag is your record to how the unit is functioning.

No service record (even the name of the tech) would be a small red flag for me.

Request the oil delivery history and if you feel your gauge is accurate enough, try to determine the gallons per day of use. We can do that from delivery to delivery, but I've never had a gauge that could give me that info.

Mike Speed 30 Member

The requirement for a "service tag" is unknown here in the Midwest where I live. But, except in some few metro areas, there is no licensing of service technicians or requirements for permitting. There are no applicable state regulations. It's hard for people in the East to comprehend that, but probably 90% of the U.S. is that way.

spott Member

D, I believe you're the best judge of your oil usage. You can tell if you're using more oil, even in the short haul.

If you seem to be running the same amount of time and the weather is about the same, one thing I would find out is if the tech put the right nozzle in for you. It seems like a small thing, but if he put a larger nozzle in you will burn more oil in the same amount of time.

For example, if you had a 0.75 and he put in a 1.00, that's an extra 0.25 gal for every hour your boiler runs. Although it sounds like a small thing, if your boiler runs a total of four hours a day at this time of year, that's an extra 30 gallons a month and the extra oil is just going up the chimney.

As Bud said, you should have a tag whenever they do work, which should tell you what they put in for parts like the nozzle size and filter, etc. In MA, they are required to leave one and if they didn't leave you one, I would request one and find out exactly what was done.

There are times when they don't have the proper nozzle for you boiler, so they put in something close and make the burner adjustments to accommodate it. It will work in most cases without problems, but most likely it's not as efficient.

zoesdad Member

I think heatpro would have covered this in post #2, but I wonder if you are using your boiler for domestic hot water and the service guy cranked the low limit way up on the Aquastat. I believe I’ve heard of that happening in the past, especially if the homeowner mentions his domestic hot water is a little too cool.

So, your burner would be running more and your boiler would be hot even when there is no call for heat from a zone—but I think that was covered by heatpro.

I live 20 miles NW of Philly and in my area, the service guy would leave a sheet which had check boxes for the Standard Silver Service—but the boxes were never checked. He would write in, however, any parts he replaced. I just assumed there was no legal requirement here in PA to leave a record. Could be wrong. (I do my own service now.)

doughness Member

Often, the nozzle is changed during annual maintenance. If nozzle size was increased, efficiency goes down and oil consumption goes up. It's an easy way for oil companies to sell more oil and increase profits. When customers want plenty of heat, they are happy to oblige. Most boilers put out more heat/btu hour than the system can radiate so the higher boiler output is wasted.

sidny Member

What is your stack temp? It shouldn't be more than 250-300 degrees above the water temp plus the boiler room temp. It was already said on another post that maybe some of your heat is going up your chimney. Most boilers are over fired, as some oil dealers like to sell a little more oil. How clean is your boiler? Did you see it while it was open? What is your draft reading? Did the serviceman leave a service report?

davidm Member

Thanks, everyone. You've given me some ideas to follow up on.

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