Be Prepared

Feature Story

Testing your equipment before the onset of the heating season can save a lot of headaches

By George Lanthier

A lot of my recent articles have focused on meters, testers and gauges, and in response to those articles a lot of my e-mail surprised me, but I guess in some ways it didn’t. When writing articles I’m finding out that I sadly make too many assumptions, the worst being that people will not just look at the article, but will in fact read it.

I also assume that people will look at the diagrams and pictures and put them with the story, but that doesn’t seem to be happening in some cases, either. Finally, I guess I’m learning that more apprentices are reading the articles than I thought and my assumptions that they were taught the basics appear to be somewhat off, too! So, I’m going to jump into the deep end of the pool and try to resolve and correct a lot of my assumptions in this article.

Even if you’ve never been a Boy Scout, we’ve all heard the old axiom to “be prepared.” With test equipment that should mean that at the beginning of the heating season you check out all of it. With combustion testing equipment that may in fact be a matter of doing some checks more than once a year, but we’ll come back to that later. With most of the equipment that a heating serviceman will need during the winter, that normally means you’d have to get going on the project somewhere around Labor Day. Do my meters and testers, where needed, have new batteries? Are my pump-testing tools ready to go? Have all of my testers been checked for accuracy and operation?

Electrical testers
Many of the testers I have called out, such as the V-O-M, require one or more batteries for their operation. It’s always a good idea to replace them in the fall, maybe tying it into daylight savings, and don’t forget your CO and smoke alarms, too! Without the correct battery strength, the meter may be worthless when you need it most.

It’s also a good idea to keep a wire-wound resistor around and check your resistance scale. A thorough check would also include just plugging it into a wall socket and seeing what you get for an AC voltage test. An even more thorough test would be to also check it on a capacitor, if your meter will do that for you, and checking the new battery going in against the one coming out. Light bulb and neon-type testers, Wiggy’s and other voltage testers should not only be checked before the season, but should also be tried on a known power source before each and every use.

Although clamp-around ammeters are an invaluable service tool, they should also be checked from time to time on a known value, too. I don’t know what else you carry for test equipment, but check whatever you have from time to time against a friend or co-worker’s equipment. At my last shop, we had “master equipment” that everything was checked against. If one technician is wrong then we are all wrong and if you are all wrong, you’re not wrong, you are uniform, something that I was taught in the military and in this litigious society a good nail to hang your hat on, FACT!

Pump-testing equipment
As I’ve already stated, a lot of confusion can reign if you work in a shop with five or 55 techs and everyone is setting pumps by their own gauges. I bet you never gave that much thought, but since heating and fire starting is my life, I have. With a simple pump pressure change of just 10 pounds a firing rate can change quite a bit.

Let’s look at what happens with just a 10-pound error between gauges and a 1.00 gallons-per-hour stamped nozzle. By one guy setting the pump for what he thinks is 100 psi when in reality it’s 110 psi the firing rate goes from an actual 1.00 gph to 1.05 gph. With a 150-psi pump pressure and again a gauge that’s 10 psi off, the firing rate goes from 1.23 gph to 1.27 gph. Not much, you say? Oh, really, well try doing this with a continuous reading combustion tester going and see what happens. Keep in mind that I also kept the error factor small, what if it’s 15 psi, 20 psi or even more from one gauge to another, then what? Not having a vacuum gauge that reads correctly can also cause a lot of unnecessary service, callbacks, expense and customer attrition, but I’ll stop at that.

If you use a hand pump for oil lines, is it in good shape? What condition are the internal diaphragm and seals in? What condition are your hoses and fittings in? Remember, this tool is essential for oil-line work and after too many bad episodes with blowout guns I won’t use one ever again, FACT!

Finally, look at your combustion testing equipment. With electronics check it against another unit or, my favorite way, against a “wet-kit.” Yup, it turns out that if you have a wet kit in good shape it will be as accurate as electronics, not just as fast and, of course, you also lose the ability to print results that can be very important.

I’m going to give you the short version of checking your wet kit, but if you want the real deal you can find it soon on our Web site,, in an area we call “The Mine.” It’s a great place to go digging for info and you’ll find this soon on “Level Four.” As I’ve said, this is the short version and just covers checking your test equipment.

This material was originally published in The Councilor of the Better Home Heat Council of Massachusetts in 1979 and then in Fueloil & Oil Heat, September 1991. It was again published as excerpts in the text COMBUSTION & Oil Burning Equipment in 1995-2000. This information never seems to go out of date.

Before performing any tests, the draft instruments must be checked to insure good test readings. When checking the dry-type draft gauge, check to be sure that the gauge operates smoothly. By twirling the hose end or by inhaling across the tube, a negative pressure should register and then the instrument should return to zero. If it does not return to zero after a couple of samples, the instrument is most likely defective.

Checking a draft gauge requires that the gauge be level and zeroed. However, if this instrument does not return to zero after a couple of samples, thoroughly clean the instrument and recharge with clean gauge oil.

The first thing to checking the smoke tester is to insert clean test paper into the instrument. Block off the end of the sampling tube. Pull plunger handle about 1 inch and release. The handle should return to about the original position. If no resistance is met or if the instrument does not return to original position, the instrument should be checked for leakage.

An atmospheric test should be made of the instrument. If, after 10 full strokes, a smoke reading is observed that can be measured on the chart, another test with a clean test paper should be performed. If the instrument still measures smoke, the instrument should be disassembled and cleaned. Be sure to lubricate the cylinder of the plunger-type with the proper material after servicing.

Testing of the CO2 analyzer should be done after about 200 samples have been taken, following long storage periods, or after coming from extreme temperatures, such as cold service vans or hot service and sales car trunks. If the CO2 scale is down, two or three drops of water or fresh fluid added to the instrument should bring up the scale fluid to the zero point. If water has been added more than a few times, a test should be performed to establish fluid strength. Here’s an easy way to obtain CO2 to establish fluid strength and keep in mind that it is an increase in percent CO2 on the one-and-the-same sample that indicates weak fluid.

After taking a sample in the usual way, which requires 18 full depressions of the aspirator bulb, the instrument is inverted twice and the test result is recorded. Then the instrument is inverted or tipped twice more. If the CO2 percent reading rises or falls more than 0.5 percent, the fluid is becoming weak and should be replaced.

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 the
thermometer in boiling water. If the instrument reads 210-215F, the instrument is OK.
Thermotest. Check the thermometer against a thermocouple or good mercury thermometer.
Compare temperature. Compare the temperature in a warm air furnace plenum against either of these two instruments. If, when using a Bacharach thermometer and 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.

Well, hopefully that clears up a few things, and if you’re looking for some of this equipment, check out our e-store, we have lots of cool tools and are adding things all of the time. If you get stuck looking for something give us a yell, we know where the good stuff is.

See ya.

George Lanthier is the owner of Firedragon Enterprises, a teaching, publishing and consulting firm. He is a proctor and trainer for the industry’s certification programs and is the author of nine books on oilheating and HVAC subjects. He can be reached at 132 Lowell Street, Arlington, MA, 02474-2756. His phone is (781) 646-2584, fax (781) 641-7099 and his e-mail is

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