CO TESTING

The Bacharach program begins with a discussion on CO — what it is, how it is generated, and why it is harmful. From there, Dwyer encourages participants to make CO detection a part of every routine furnace checkup. In fact, it should be “one of the first things you check when you enter any building or mechanical room,” says Dwyer.

This is especially true for furnace inspections that must be done in confined places. “It should be a number-one criteria,” says Dwyer, “to make sure this is a safe place [for the tech] to be in.” Because CO cannot be detected through any of the five senses, it is important for a service tech to use a CO detector before working on the furnace.

Dwyer tells his students it also is important to check the level of CO again before they leave, after they have completed their service, to ensure that the home is safe for its residents. Dwyer also recommends that the technician leave a consumer brochure on CO health effects, and to recommend the use of CO alarm/detectors.

Dwyer also says the technician must inform the homeowner that s/he limited the CO testing to the furnace if that is all they tested. If CO is measured in the living space and testing verifies it did not come from the furnace, the technician must decide if he wants to test all the combustion sources in the building, or refer it to someone who will complete the testing.

If high levels are found while testing, it is the job of the technician to find out if this is due to a problem with the furnace or if it is generated from another source. According to Dwyer, one of the major causes of CO poisoning is automobile exhaust. A home can have traces of CO if it has an attached garage and the homeowner frequently warms up the vehicle while it is in the garage.

Another source of CO can be from unvented or poorly installed gas and oil appliances. It can also be produced from improperly sized or installed vent systems.

COMBUSTION ANALYSIS

The premise of testing combustion is to make sure that the furnace is working up to the standards that the manufacturer claims. Dwyer explains that although furnaces have a rated efficiency, they must still be tested in the field to determine if this efficiency is correct.

If a new system is not tested at installation, it is guesswork; this testing includes fuel pressures, stack draft, temperature rise, and static pressure.

Combustion efficiency is determined by how well heating equipment is converting a specific fuel into useable heat energy during a period of system operation. Using the proper test instruments, a technician can determine the efficiency at which the furnace is actually working. This is an important test because improper combustion can lead to the generation of CO, inefficient operation, or overheating.

Dwyer explains that it comes down to simple chemistry. If there is too much or too little fuel mixed with the combustion or primary air, this can result in CO production. If the system is operating hotter than necessary, this can also create problems.

Overheating can cause damage within the system, or it can cause objects near the system to catch fire. And, it can cause the system to cycle on the limit or safety.

Bacharach’s course teaches techs how to check system efficiency by using test instruments to measure flue gases for content and temperature. It also teaches how to measure stack temperature and draft. This allows the technician to determine if there is a correct amount of air and fuel to create the energy for operation. It will enable the technician to determine how much heating value the equipment is losing, therefore determining efficiency.

Dwyer says the proper location to measure flue gases is before the introduction of dilution air, through a draft hood or barometric control. If systems do not have access to this undiluted air, an access will have to be made by drilling a hole in the vent connector and sealing it after testing with a high-temperature silicon product. If the oxygen measurement changes dramatically when an air handler comes on (in forced-air systems), there is likely a crack in the heat exchanger.

MAKE IT A HABIT

These applications are not time consuming, but, according to Dwyer, a great number of companies do not measure combustion products or CO. There are a few reasons why.

“Some technicians only use it when they think there is a problem,” said Dwyer. “But you don’t know there is a problem unless you test. Customers assume technicians provide accuracy, not guesswork.”

For those who do not test at all, it comes down to ignorance or lack of education on proper testing procedures. That is why Bacharach is making it a mission to reach as many hvacr contractors, manufacturers, fuel companies, and others in the business as possible.

The message is not only to keep contractors physically healthy, but financially healthy as well.

Dwyer says many companies also can avoid litigation if they properly check for CO. It also provides verifiable accuracy for the customer. It can even help out a contractor’s reputation.

“Many are on the threshold of litigation and don’t know it,” says Dwyer.

He explains that if a technician provides a service tune-up and says the system is OK, he needs to make sure that it is backed up with documentation. The homeowner could have another technician come in who tests and measures the performance of the system, only to find out that combustion and CO measurements have not been done.

“If you don’t test, you don’t know,” says Dwyer.

To find out more about Bacharach’s training or to find more in-depth information on CO testing and combustion analysis, go to www.bacharach-training.com (website). You can also find information on upcoming seminars and how to attend.

Publication date: 03/11/2002