Furnace Destroyer #1 – Design

Heat Exchanger Destroyer #1

By: Steve Holland




Design. The first place to look if you’ve lost a heat exchanger!

Who would have ever though that a designer could ruin a heat exchanger? It happens each and every day. There are three phases of design that cause heat exchangers to fail.

  1. The manufacturer design. Many manufacturers use proprietary methods when developing heat exchangers. Carrier, for example, had a secondary heat exchanger that used a poly-propylene coating. In some furnaces, this coating failed; resulting in secondary plugging and/or heat exchanger leakage. The Lennox Pulse was another that ran into a few issues. Today, we are seeing many designs that may pose failure in the future. Understand this, most heat exchangers fail as a result other than manufacturer design.
  2. The designer of the job. At Mr. Holland’s we call these folks “Comfort Advisors”. Many comfort advisors fail to properly measure duct systems, or fail to perform load calculations, resulting in pre-mature heat exchanger failures. This is why we require all of our comfort advisors to measure the home, measure duct systems, and, in some cases, perform a static duct pressure reading on the system.
  3. The install designer. Every furnace built and designed must be installed by the installation technician. This means that after the manufacturer builds the unit, and after the comfort advisor sizes and designs the job, it has to be installed. Many mistakes are made at this phase of the process, resulting in pre-mature failures of heating and cooling systems.

Poor Static Duct Pressure

Homeowners Advice:

Never assume that just because your neighbor referred a company or the fact that an HVAC company has been in business a very long time that the job will be done properly. Pay attention to the following:

  1. Was a load calculation performed by the sales person?
  2. Did the sales person examine the ducting and perform a cfm or static duct reading?
  3. Are they accredited by the BBB?
  4. Make sure that the installing contractor gives you a complete workmanship guarantee in writing, and a host of other guarantees.

Poorly Installed Duct System

Contractors Advice:

  1. Hold your sales staff accountable by making sure that they perform a load calculation and duct calculation.
  2. Stand behind your work
  3. Spend the extra money and get BBB (Better Business Bureau) accredited
  4. Quit being so cheap. Spend money on training, education and staff development

Manufacturers Advice:

  1. Don’t be arrogant and think that your engineers are smarter than HVAC techs. They may know physics and properties of heat transfer – but, some simple changes from HVAC guys can give that furnace a better and healthier life.
  2. Use more stainless steel and good quality stainless. Many secondary heat exchangers fail because they are not made of stainless steel.
  3. Listen to your end-user customers. That’d be me and other HVAC contractors out there that install your equipment each and every day.

I hope that the information that I provided was useful. Remember, the best way to keep homeowners and customers safe is by training and educating service technicians.

Steve Holland

“Changing the HVAC industry – one tech at a time”


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Mr. Holland Tours Wisconsin

Steve Holland’s Tour comes to a close

What an amazing week! This week, I traveled the State of Wisconsin to visit several Tech schools.

I began the week in Wausau at North Central Technical College and ended it at Madison Area Technical College in Madison. The week prior I traveled to Milwaukee and Eau Claire.

I really enjoyed the Wausau class, and the guys seemed to really enjoy the seminar. There were many good questions asked about air flow, setting up boilers, and much more.

Both classes in Madison were excellent, and this group was a hilarious bunch. I had a great time at all of the schools this year, and look forward to meeting and visiting again next year.

In Eau Claire, as always a pleasure. All I have to say is WOW on the new training lab that will be built at CVTC. I’m excited to see it.

Milwaukee – I really enjoyed that visit. I found out that one of the instructors and I both worked at the same place. Congrats to Milwaukee on winning the Tech Competition. Excellent questions were asked across the board by all students and instructors.

Here are several topics that students in HVAC program wondered about:

One student asked; “Is their driving record important?”

Another asked “What can you do if your employer is not proactive in training and education?”

We also talked about pressure switch failures and the importance of air flow and combustion analysis.


Here’s my take on these subjects:

Driving record

I think it is essential to maintain a good driving record, especially if you decide to be a heating and air conditioning service technician. Many insurance companies will not insure a technician or installer that has a poor driving record. I suggest that if you have a poor record currently, that you start fresh and do whatever you can to get it cleaned up. At our company, when we hire technicians with a poor driving record, we make them part of an install team. These teams typically ride together, allowing the main driver to be the one with a good record. Occasionally, there are sales positions that allow a sales person to use their own vehicle to meet with customers. This is also another viable option.  Keep it clean for a year, and you most likely will be okay.


What can you do if your employer is not proactive in training and education?

The first thing that I suggest is that you be a leader in the company. Talk with your employer about getting you involved in more HVAC education, and be positive about it. I also suggest that you be a self-starter and self-guided. There are many resources available online for all HVAC students and technicians.

One thing that I do at all of my seminars is provide a list of resources for students via email to the instructor. If you have an employer that feels that education is not important, well, you may have to move on. Lastly, if you find an employer that is proactive and willing to invest in you, be loyal in return, and don’t always worry about that hourly wage. Sometimes you’re better off working at a company with a great culture coupled with a proactive approach to education than the company that is miserable to work for.


Pressure Switch Failures, Air Flow and Combustion analysis

At our company (Mr. Holland’s Heating and Air Conditioning), we change hundreds of pressure switches each year. Currently, we are heightening our awareness on furnace tune ups and making a bigger attempt to test every one. The three main failures of a furnace are often the pressure switch, the ignitor, and a dirty filter.

When it comes to air flow, it’s probably the most overlooked and underappreciated check for a furnace. Many heat exchanger issues start as a result of a lack of air flow.  Technicians today must understand all of the testing methods for finding air flow problems. It makes no sense to replace a furnace or air conditioner that is short of breath.

Combustion analysis is yet another missed opportunity for technicians. I suggest that all gas furnaces, boilers and oil burning furnaces go through the testing and adjusting process. Many heat exchanger failures can be identified via the combustion test.


In closing, I would like to thank all of the instructors at all of the schools. I am excited for the future of the HVAC industry, and I really enjoyed meeting with the hundreds of students.

Milwaukee Area Technical College  – Milwaukee, WI

North Central Technical College – Wausau, WI

Chippewa Valley Technical College – Eau Claire, WI

Madison Area Technical College in Madison, WI


“Let’s change the industry – One Technician at a Time!”


Steve Holland



For more information contact Steve Holland.

Heat Exchanger Safety – visit www.heatexchangersafety.com

Mr. Holland’s Heating and Air – visit www.mrhollandsheatingandair.com