HVAC routine please help...

I am new to interNACHI, even though I had joined NACHI in 2004 right after I finished my H.I training at AHIT. To make a long story short I got side tracked by some remodeling jobs and never got to start my H.I business until…now. But I’m back and love InterNACHI web site. So much more has been added (NACHI TV etc.) and the message board is full of good advices and tips. As I was practicing some inspections I realized that my routines are not as smooth as they should be. The inspection of the HVAC system for example is a little chaotic for me with lots of back and forth inside/outside and hope that some of you could let me know what are the steps of your routine of a A/C split system inspection (plenty of these in South Florida). I have the books by Roy Newcomer (from the AHIT training) but they don’t includes a good routine to follow so I’m kind of stuck. Thanks again for your help.


There are a few variables in testing the HVAC system.
One would be the outside temperature and the type of system. Also if an inspector has a HVAC background he may do CO tests, use an amp meter.

First the advance heating course Nachi offers is very good.

I personally start the HVAC inspection by examining the outside unit. I take a picture of the data plate to note the size, capacity, brand and age. I check the refrigerant lines, if unit is level, open exterior disconnect and see if the proper size fuses are being used in accordance to the manufacture’s specifications. I also examine the exterior condenser for any damage, if it is dirty is it buried in vegetation.

On the inside depending on the temperature I either run in heat or cooling mode. I turn it up really high or down really low so I hear people complaining on how hot or cold it is. I also note on my report the temperature that day and if I ran both the heat and air.

I had a client wanting a new air conditioner as he said I would give him one!! I looked at my report that I did in early march and it was 35 degrees. It stated that could not be tested due to temps below 65 degree. He then hung up!!

I take off a lot of floor registers covers looking for debris, insects and moisture. I check air flow at each level. I verify there is a heat source in each room. If there are space heaters I note them as being tested or not being tested.

I usually inspect the furnace last. I check the air conditioner when I first arrive in the utility area and use a laser thermometer to see if I am getting a 15-20 degree temperature drop. I look for records of previous service. If there are no recent records I explain that they should be professionally serviced at least every other year. I make a comment in report that It is recommended a HVAC specialist review to ensure proper operation. I also talk about Home warranties as if you are concerned on the age of your systems this is the time either the seller or you can purchase a warranty.

At the furnace I check the filter. I use a Rigid boroscope on some systems to look at the heat exchanger. I note the % of the heat exchanger visible. I check the sequence of operation when I am done looking at the interior cabinet. I also take a picture of the data plate. I note any additional components like a humidifier or condensate pump.

This is a very brief explanation of my inspection. Look for moisture, signs of backdrafting, check the flues, gas lines, wiring. Does it have an electrical disconnect. I am sure I have left out a lot but this is just a simple explanation.

The guys on here have a lot of knowledge and the advanced HVAC course was helpful for me.

Boilers, heat pumps are common systems that have additional areas to inspect.

I hope my simple explanation has some benefit to you.

Hey Patrick,

We get info off the data plate, like the manufacturer, tons, date, RLA, Max fuse or breaker size and minimum appacity. When we are at the electric panel we make sure the unit is on the proper size breaker. Many times we find units that are on an oversized breaker, if it’s on an oversized breaker that can void the manufacturer’s warrant and may not provide the proper over-current protection for the unit. The same goes with the air handler unit. We check the service disconnects as well.

Make sure the air handler matches the outside unit. The air handler can be ½ ton larger, but not smaller.

We let the system run for a while then check the following - We amp probe the conductors to the outside unit while inspecting the electrical panel, and make sure the amperage draw is not above the RLA that’s on the data plate. The unit should be running at 60-75% of the RLA.

We take a look at the evaporator coil to see if it’s heavily soiled, clean or whatever it may be. Take a look at the condition of the filter, check each register with a thermometer and make sure cool air is coming from them.

Make sure the condensation line is flowing and that the suction line is insulated, especially if it’s routed in the attic space.

Feel the suction line and make sure it’s cold and feel the high pressure line and make sure it’s warm.

We get a temperature split after the system has been running for a while and make sure the difference between the plenum temp and return air temp is within 15 – 22 degrees. Some may tell you temperature splits are useless, but we choose to take them.

When we operate the heat we get a plenum temp. We also amp probe the strips to get an idea of their rating, normally 5 KW, 7.5 KW or 10 KW on a residential home.

If the unit is a heat pump we do pretty much the same except when in heating mode, you want to make sure the condensing unit disengages when turned to the “Emergency Heat” setting. You also want to make sure you wait a little while before changing from cooling to heating. I typically wait around 10 minutes.

We check the accessible duct connections and the condition of the duct work while inspecting the attic space. We also recommend our customers get a duct test performed. Here in Melbourne the electric company does duct test, by pressurizing the ducts and identifying the leaking connections.

That’s what we do in some waht that order. It’s beyond the SOP’s, but we choose to go beyond them. It’s a personal choice you have to make. If you stick to the same routine on every inspection, it will become smoother and smoother for you. I am sure others will chime in with some additional info. Also, the NACHI’s online HVAC course is very informative and well worth the price.

Hope this helps and good luck to you [FONT=Wingdings]J[/FONT]

Thanks guys for the info. I do have my eyes on the advanced HVAC course but will have to wait a little longer. $200 is a little steep for me right now but I’m hoping to take it within a month or two. Until then, your posts will help a lot. I’ll keep checking if anybody else has some other tips. Thanks again.

Turn the heating system on and let it run until everyone complains about how hot it is. Then turn the cooling system on and let it run until everyone complains about how cold it is.

If you ever get a callback, you can remind them of how everyone was complaining.


17 hours of training (21 CE)
182 page course book included
exam (take as many times as needed)
and certificate
Learn at your own pace - full control - Unlimited viewing time - play, stop, leave, come back days later, play again.

I can get you a deal on the price too. ben@nachi.tv

Folks don’t think twice about spending twice this for a moisture meter or a ladder. I paid a whole lot more per semester for HVAC training and had go for months to complete. This is a great price to learn about an area where most inspectors are extremely weak. If I were just starting out in HI this would one area I would spend the money and forget the yellow pages ad or something else that is not going to give such a good return on my money. I know money can be tight in the front end of this business but I would put aside a few buck from every inspection until I had enough to take the course, along with all the free ones. You can’t find a better source for CEs. Good luck on your business. BTW, if I can ever help you out give me a call or email me.

We only have about 3 months to inspect A/C systems here… As of this date, We’ve only had one day above 65 Deg F. Our biggest A/C unit is Lake Michigan that’s only 2 blocks away on the west side of the lake. I haven’t found a way to inspect that without trampling on either the DNR’s or EPA’s toes…:slight_smile:

I’d like to hear the narrative/disclaimer that you use in your report about that restriction. Please.

My inspection of a/c’s is pretty much the same as above although I start at the condenser before I enter the house. I pull the access cover off and check the wiring, capitors and compressor area for corrosion or evidence of past overheating.

Next when I’m inside I turn on the system (its never too cold to inspect a/c’s here on Maui) and give it about a half hour to stew. Then I go back outside and double check compressor area and take some temps of the refrigerent lines at various stages, listen for odd noises and measure the amp draw. I then put back the cover.

Back inside I check the delta at all supply registers and the return air register.

And finally I check the air handler, evap coil and condensation drain piping which is usually in the attic here.

Some inspectors dont remove the condenser access covers and that is up to you but if you remove one (electrical panel for example) you should be able and willing to remove them all.

Good Luck


The A/C system relies on natural convection currents and is unreliable. The measured temperature difference could be as little at 0 degrees and as much as 18 degrees. Unfortuantely, the 18 degree difference usually occurs when the outdoor air temperature is in the upper 60’s and you have plans to be outdoors. There is no way to turn off the system under these conditions. Recommend reading the section on the HEATING SYSTEM to verify this system was functional on the day of inspection. It is beyond the scope of a home inspection to be technically exhaustive so the water temperature was not measured. :shock:

:mrgreen: Fantastic Greg. :mrgreen: