Noise and moisture, Part II

Feature Story

A doctor’s stethoscope may be your most important tool in diagnosing chimney problems

By George Lanthier

I know I left you hanging last month, but I didn’t want to give the best part away, so finally, my $64,000 solution to the noise problem. Remember my ‘Lanthier’s Laws” article about noises and using a stethoscope? Well, as it turns out, it’s really not a $64,000 solution, but rather a $20 solution to a very expensive problem that has probably cost this industry a number somewhere between the two. I’m going to bring back Bubba and B-B to explain this on a visit to Mrs. Acoustica’s home where a new unit has just been installed by the boys over at Friendly’s Oil.

‘So, should I grab the tools and test kit and stuff, Bubba?” asks B-B.
‘No, hold off on that for now, B-B, I have what I need right here,” responds Bubba.
‘A stethoscope, now that’s a good one,” exclaims B-B. ‘Is this one of your Uncle Brucie’s tricks? Oh boy, I just can’t wait to see this!”

Bubba and B-B enter the home and while walking up to the door Bubba takes notice of the chimney location. This is a key piece to his plan and he will need to know that to help gain his credibility.
After talking to the customer and actually listening to her, Lanthier’s Law No. 1, Bubba then says he would like to confirm that the noise is coming from the same wall as the chimney.

‘That’s the wall the noise comes from, right ma’am?” asks Bubba.

‘That’s the one,” answers Mrs. Acoustica. ‘How did you know that?”

‘I’ll bet the noise is also worse at night, right?” asks Bubba.

‘Yes it is!” exclaims Mrs. Acoustica. ‘And just who are you?”

‘Well, I’m Bubba Belcher and I’m a combustionologist and that’s why I’m here. I’m just trying to find the problem,” says Bubba. ‘Would you please turn up the thermostat so we can get the burner to run?”

Now, at this point he takes out his stethoscope and, by the way, when you do this don’t use the expression ‘Excuse me while I whip this out;” it’s been known to make people dive for cover.
Bubba places the earpieces in his ears and starts to actually listen to the wall. At this point and from experience I will tell you that you have to make curious noises. For example, ‘Hmmm, wow, oh boy, hmmm, uh-huh, hmmm,” while you’re listening to what sounds through a stethoscope like a B-52 in the chimney wall. At this point comes the magic.

You ask the customer to listen. Let me tell you, I have had grown people cry when this happens, no kidding! The most common responses have been things like, ‘Can you hear that?”, ‘I’m not crazy?” and ‘It really is very bad, isn’t it?” Always agree. It’s the age-old axiom of ‘the customer is always right” and in this case, they really are.

At this point, you’ve both agreed to the fact that there is a problem and the customer no longer feels that you believe them to be crazy. Score one for the good guys, us!

Now comes the problem. When the customer asks if you can fix it you must be truthful and say ‘No,” but you do know who can, a chimney-lining person.

Well, that’s it and a lot of people will really freak out over this one, but you know what, it’s all a matter of opinion, and now you’ve heard mine. If you want to deny the problem, that’s OK with me, but don’t complain to me how you’re losing customers to the gas industries by keeping your head buried in the sand. By the way, you really need to go listen to a brand new, high-efficiency 90+ gas-condensing unit and you won’t hear anything, for the record. Zero, nada, zip, the big donut, stealthy, absolutely quite, FACT!

In Part I, I told you we would look at the condensing problem. If you remember I said: ‘the chimney in a 10-year old house has already started to decay and if you are seeing ‘pigeon droppings’ under the flue-pipe joints, you have an additional problem.”

Those ‘pigeon droppings,” or white spots on the floor under each and every joint in the fluepipe, are from water. It means that your flue gasses are under 350(F gross or 285(F net and it’s raining in your flueways. If you’re seeing this in the basement, imagine what’s going on in the chimney, and never mind at the bottom, what about at the top?

The solution is again a chimney liner, yet the oil industry fights these things like they were a curse. Why? ‘Too much money,” say some. You’re not paying for it. ‘Not needed,” say others. Yeah, well, what are we talking about it for?

Look, the fact of the matter is most of today’s new equipment is highly efficient and that’s what the customer wants. Most of the equipment going in is running at one-third to one-half the stack temperature of what you are pulling out. In addition to the stack temperature problem there are drafting problems. Did you know that if you cut the stack temperature in half, you cut the thermal draft output in half? We discuss this in my book COMBUSTION & Oil Burning Equipment, but for now just take my word for it. If you don’t want to believe me, buy the book or another one that has the same information.

That book is titled the Handbook of Domestic Oil Burning. Floyd Olmstead wrote it in 1926 and he is the dean of oil burning in this country, and I guess it proves that it does take us a while to get the message. A lot of problems can come with more efficient equipment if you try to service it the old-fashioned way, but if you sell state-of-the-art, learn to service it the same way.

Remember, I said that you don’t pay for it, the customer does. It’s the old pay me now or pay me later game. Remember my own chimney experience? Have you made friends with a CSIA sweep yet? OK, let’s look at the other side of this story, moisture.

If you get a complaint from a homeowner about those pigeon droppings, the first thing to check is your thermometer. Many of us have switched to digital, thermocoupled, infrared, high-emmisivity jobs that will tell you even the time and the temperature, but for many it’s still the standard Bacharach Tempoint,

The next part of this is taken from my now-classic article, ‘The Care and Use of Combustion Test Equipment,” originally published in Fueloil & Oil Heat in September of 1991. Excerpts were also published in COMBUSTION & Oil Burning Equipment and just recently in my article ‘Be Prepared” in these pages. The complete article can be found at

Checking the stack thermometer: The thermometer should be checked for obvious damage and/or a bent stem. If the instrument appears in good condition, the following tests can be performed to check accuracy:

Boiling water test. Insert thermometer in boiling water.
If instrument reads 210-215°F, instrument is OK.
Thermotest. Check thermometer against a thermocouple or good mercury thermometer.

Another good test is comparing temperature in a warm air furnace plenum against either of these two instruments. If, when using a Bacharach thermometer, it is found that the instrument has wandered, it can be recalibrated by securing the hex-shaped nut on the back of the Tempoint and by rotating the black dial to correspond to the correct temperature setting.

When using any of these instruments, care should be taken to handle them properly. Proper use hinges on the proper insertion depth of the thermometer’s bimetal which is at the end of the probe. The retaining clip is especially conducive to obtaining the desired insertion depth.

When analyzing problems such as the ‘pigeon droppings,” the temperature of the flue gas has always been, and still is, one of the single most important tests we perform on heating plants. From knowing that a 1-percent CO2 change will affect temperature 25(F, we can make burner adjustments with accurate thermometers very easily. So, it is very important that we use and maintain the equipment to the best of our ability.

If you also find ‘beach sand” in a fluepipe it’s an indication of two problems, one that the fluegas isn’t hot enough and two, that there is too much excess air in the mix that is also lowering the CO2. When you dump out that beach sand have you noticed that it’s pitched from the unit to the chimney? Sure, it gets cooler as you go along. Have you noticed the maroon paint streak, too? That’s not paint, it’s rust and I would suggest that if you can to flip the pipe over when you put it back up it’s a good idea. If it is really bad, you may want to consider replacing it.

If you really want to prevent noise in the oil-fired home get smart about liners and stop blaming the equipment manufacturers. If you want to stop condensing in the fluepipe, I would suggest you take a reading as the pipe enters the chimney or venting device and make sure that it’s over 350(F gross; if not get out the umbrella. As to the chimney moisture, well I think we’ve already covered liners, so that’s that.

See ya.

George Lanthier is the owner of Firedragon Enterprises and the author of nine books on oilheating and heating systems. He is a teaching consultant and expert witness on oilheating systems. He can be contacted at 132 Lowell Street, Arlington, MA 02474-2756. His phone number is (781) 646-2584 and he can be faxed at (781) 641-7099. He can also be contacted through his Web site at

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