Matt is our Director of Technical Services and has been with East Coast Metal Distributors since March 2016. He is devoted husband and father to three boys in the Charlotte, NC area. He stumbled into HVAC completely by accident and is now climbing within the industry to be the best he can be.
On a recent cold afternoon, I received a call from a frantic service technician. He diagnosed a faulty gas valve in a gas furnace, arrived on the job site with a new gas valve, taken time to ensure the new valve was installed properly, and then observed in horror as the exact same failure to ignite happened with the new valve. Now, let us all be honest with ourselves … after all, nobody is watching … we have all been that technician. We have all experienced the horror of realizing our diagnosis is wrong. Not a good feeling … and far worse if the furnace is in a closet and the homeowner is standing over your shoulder.
After the technician took a few deep breaths and regained composure, we began to go back through the furnace together.
Power surges are commonly blamed when controls go bad on high-end units. I am not sure how often this is an accurate diagnosis versus how often this is just an easy scapegoat for unexplained parts failures. Plus … let us all be honest for a minute and acknowledge that as technicians we have all been guilty of condemning a control board because the system was operating abnormally and we did not understand what was happening … so therefore it must be that fancy looking control board.
When I was first starting out in the HVAC Industry as a new technician, it was a common joke at my first company that you could tell the longer a technician had been in the industry by looking at his tool bag. The joke was that while newbie technicians such as me had a tool bag loaded with tools, the veteran technicians had a mostly empty and worn bag that had a few things here and there in it. Granted, I learned a lot from the senior technicians at that company, but I did not carry that habit with me. If you want to do a job correctly, then you must have the correct tools.
Robert Frost once famously fretted over which two diverging roads in the woods to take. He presented the case of a traveler that has come to a crucial decision that must be made. The same theme often rings true in HVAC diagnosis. The technician finds themselves at a diagnostic crossroads, if you will, and a choice must be made:
The variable-speed blower motor will not run. Is it the board or is it the motor/module?
My invertersystem is throwing an error code. The service manual says it could be the compressor or the board.
My HVAC system will not communicate. Is it the indoor control board, the outdoor control board, or the wiring?
Today I am going to review troubleshooting an inverter compressor and the control that drives it. Often in analyzing service manuals you find flow charts that look like this:
A common service call that arrives in the latter days of summer is a clogged drain line. It is par for the course in the Southeastern United States; we have warm temperatures combined with high humidity. Air conditioning systems work to address both the temperature of the home (sensible heat) as well as the humidity of the home (latent heat). As the HVAC system runs it absorbs both heat and humidity from the home into the evaporator section of the unit. The heat is transferred outside via the refrigerant lines and superheated refrigerant while the humidity is transferred outside the home via the HVAC system drain line.
Slime in a drain is a universal problem. It occurs in shower drains, sink drains, and even appliance drains. There are many variables that can increase the likelihood and frequency in slime forming in the HVAC drain system. However, two key ingredients are always present: food and moisture. Food is provided by dust or dirt that manages to get into the HVAC system. This dust and/or dirt will contain some organic matter which will serve as a food source. This will combine with already present moisture from normal cooling operations and provide a moist environment with a food source. The result will be a slimy gunk that will easily clog the HVAC drain line. The drain lines in an HVAC system are not under any pressure, therefore it does not take a large amount of resistance to block the drainage of condensate.
Recently I received a phone call from a colleague who had a client proposing a dual fuel HVAC system to a homeowner. This homeowner was both technically capable and very inquisitive. He wanted to accurately quantify the cost difference between heating with a gas furnace versus a heat pump. The question was simple enough, but when I was asked for the answer… I stammered. I did not actually have a straightforward solution. This bothered me a lot, and my mind had two thoughts, which were equally bothersome:
“If I cannot explain something clearly, then I myself do not truly understand it.”
“In GOD I trust; everyone else must provide data.”
My curiosity had to be satisfied. So, I went digging on the internet… and nothing was clearly quantified. However, I did find the formulas needed to answer my question. So, let’s dive into the topic of gas versus a heat pump and look at some real math on the costs. To start, we have to look at all costs in the same format. I choose to compare everything to natural gas heat and look at this through the cost per BTUH. All utility costs are based on my specific area and are clearly identified so this math could be adjusted based on your utility costs.
Indoor Air Quality is a convoluted topic on the best of days. The IAQ segment of the HVAC industry has grown tremendously overall and sees spikes of urgency during certain health crises like the annual flu season.
There are many types of IAQ technology available, and each possesses its own advantages and disadvantages. It is important to have knowledge of these technologies and be able to discuss opportune applications for them.
Ductless units or mini splits – they are the bane of many HVAC technicians. The units themselves are quiet, super-efficient, and work very well. Often, technicians will say something like, “I install a lot of these units and they generally work great, but honestly I have no idea what’s really going on inside those things.” It’s a fair enough statement. Most technicians are accustomed to contactors, relays, capacitors, AC voltage motors, and simple I/O controls. There is nothing simple in appearance about the inner workings of a ductless unit.
For starters, we have the board which is located next to a 2nd board which is then located above a 3rd board. There are no contactors or relays. The only capacitors are built into the control boards. Controls? Yes, we have controls, but not the traditional I/O kind we usually think about. Nope, these things talk back and forth. What are they saying? Who knows!
A New Year offers a fresh start and the hope of a successful year for business. The HVAC industry has been a very quickly evolving industry for many years; that pace does not seem inclined to slow. We face regularly increasing technology in the equipment being offered. Efficiency standards are constantly rising. The pool of quality technicians and installers is constantly shrinking. It really can feel like a roller coaster of a ride sometimes! Let’s look back at a major change in the past year and then discuss what is coming:
Welcome to what was intended to be my second article on refrigeration circuit practices and the importance of pulling a good vacuum on a system during installation or repair. This was going to be the time where I discussed POE oil being hydroscopic, how we can only evacuate about 50% of the moisture contamination out of POE oil (the rest must be removed with a filter drier), and how despite popular theory we do not measure the quality of a vacuum based on taking a 30-minute lunch. In truth, you have all heard this before and there are many great articles that discuss this very topic in the industry. Case in point, one of those articles inspired my new subject matter: 500 Microns = 500 Microns.