How are you testing the HVAC systems?

For my own curiousity. I would like to ask how other inspectors are inspecting the HVAC systems?

  1. Do you do a carbon monoxide test and if so what type of equipment are you using?

A very repitable heating company in my area doesnt do a C/O test on a rountine clean & check. They charge for the C/O service.

1A) Do you charge an additional fee for the C/O test? If you are testing C/O do you have a heating/cooling backround.

  1. On a heat pump or electric heat do you use an amp prope? If you do what type of equipment, if you dont how are you testing the device?

  2. On a air conditioner, how are you testing the unit? Do you use a laser thermometer or how is your method of inspection.

  3. On inspecting a heat exchanger. What is your method of inspection?

The reason I ask these questions is to help myself become more knowledgeable with testing heating & cooling systems.

I just had my furnace inspected by a pro. This is the 2nd time I have watched & saturated the technician with questions. I asked many questions & picked up a few more tips.

One tip was on a Electrostatic air cleaner. My system has 2 pull out cartridges. There is a cell on one end. Mine where damaged but functional. The spark was causing the first layer of fin to be damaged. Now I know how to inspect a damaged fin and why and what may happen.

The second tip was on jumping the thermostat to test the blower and heat.

The third tip was on the light he had to inspect the heat exchanger. It makes a big difference when the burners are removed. I dont think we will spend the 30 minutes to remove & check. I went out & purchase the correct size & type of light.

I have had on more than one occasion that I wasnt able to operate the thermostat. Now I know how to bypass the thermostat.
I understand the letters now. Y=A/C, R=Power, W=heat, G=blower, C=Common. To test he simply jumped the R & W on the circuit board.

He spent almost 1 hour to just clean & inspect the furnace. the service didnt include the air due to the temperature. He also spent an additional 30 minutes explaining in detail the answers to my questions.

I guess the reason I am posting this is in a general inspection we have no where the time to do the thourough inspection a service HVAC specialist would do.

Thanks for your time.


Dave that is correct, I don’t have the time or the knowledge to service the equipment, but I’m not in the HVAC business anyway.

I test the supply temperature of the AC and Heat, look inside readily accessible panels, and that is it.

I recommend every system be serviced by a licensed contractor, just like yours was.

Does it run is the filter clean and does the water discharge have a loop or trap.
If not please get it serviced by a qualified person .

Next the furnace

I do not have any fancy tools and do not need them I have to get my Visual inspection finished my report written and out of her in about 3 hours .
Roy Cooke

I am currently doing a visual check (which is quite limited on certain models,) plus a sulfur burn test and a C/O monitoring with instrumentation as well. I then do a performance run of the Heating and Cooling cycles and check blower/motor/belts/chimney venting/filters etc. If any trace of natural gas is evident I can do a test to determine where the leak is with my 4-gas detection device with the sniffer attached. Has worked well for me so far.

I agree with Roy in that sticking with the SOP is the safest thing to do.

We are probably all guilty of spending more time and attention in the areas we know best and giving extra attention to these areas in our reports, but spending one to two hours on just the HVAC system and a total of two additional hours on the rest of the house is probably not going to provide a balanced analysis of the entire home, IMO.

Well said Mr. B…

If you jumper R & W does that run the blower without jumpering G as well?

Remove the burners? What about gas connections?

I do not do most of what you are taking about this is well above what a home inspector should be doing ,
([size=2]The second tip was on jumping the thermostat to test the blower and heat. ) This is an example where a little bit of knowledge can get you and those who follow your directions into trouble .[/size]
I understand there is an anticipator on the thermostat and using a jumper at the furnace can cause this to burn out .
I would say this is A Good time for you to read your SOP again
[size=2]Roy Cooke …[/size]

The “R - W” jumper should only be used if the other wires are disconnected for the reasons Roy stated.

However, it will operate the furnace, but how would you know if it starts when the thermostat asks it to?? The t-stat is an integral part of the furnace operation, and only a complete system should be inspected. If the t-stat should fail, an HVAC technician should be recommended. Why, if you’re not a furnace repairman, would you want to go beyond that??

Exactly!!! Use only normal operating controls. In many places you can get yourself in some deep sewage for performing these kinds of checks unless you are a licensed HVAC tech. Anything goes awry and you are now responsible.

Yep. The good old SOP is there to protect and defend. Step out of its boundaries and you walk in “no-man’s-land”.

I generally start outside.
Type of system? Split, package,?
Location of unit/s?
Fuel gas and electric or electric?
Circuit breaker in main panel?
Age of unit/s,
Electrical disconnect/s power outlet for maintainence?
Where do the drip lines exit/go?
Refridgerant lines and insulation?
Does the thermostat control the unit?
Does it get hot or cold?
Flame pattern?
Registers in all rooms?
Type of duct?
Condition of duct? Can I see all of the duct? Mostly no.
Heat vents?
Gas lines?
Drip pans?

No CO tests. No specialized gas line leak tests. No dismantling of the unit.

I use the thermostat to turn the heating system on. As soon as someone complains about how hot it is, I know that it works. Then I use the thermostat to turn the cooling system on. As soon as someone complains about how cold it is, I know that it works. Now when they call six months later complaining about the heating or cooling system not working, all I have to do is ask, “Remember when you/Realtor/whomever complained about how hot/cold it was at the time of the inspection?” Case closed.

Not necessarily.

It depends on what one’s Client wants or needs, and what the home inspector is willing to offer. Choices, choices, choices.

For example, on my WALK inspections, which start at $49, I don’t test the furnace, usually for two possible reasons: (1) we’re at an open house so we’re not going to go around turning things on and off, or (2) the Client has already told me that he is allergic to gas and is going to replace all the gas-using appliances (range, furnace, water heater, dryer, etc.) with electric. #2 happened to me a couple of weeks ago.

For my WALK inspections, which start at $49, I’ll simply look at the furnace to see how old it is and if there are any obvious visible problems. In and out quickly and no written report—I talk, Client takes notes. Boom, boom, boom.

Russel…you posted that about a year or so ago, and I remembered it. This summer I got a call concerning the A/C working at the inspection. My report indicated the outside temperature at the time was 97 degrees, and I used your statement—and, of course, it worked!!:eek: :eek: :stuck_out_tongue:

A belated thanks for a very good idea…:smiley: :smiley: :smiley:

Here in Florida, we do not see too many gas units. Mostly electric.

I always start with the condenser unit. Check to see if it is strapped, record make, model, serial numbers. Depending on the unit, I will open the cover and inspect the fins and report on the condition if they are dirty. Always take the R.L.A. reading and in most cases the F.L.A reading. Many times this can dectect a bad compressor or fan motor. An last, I check the disconnect and insulation on the lines.

On the air handler, first I check the coils and report on their condition. If they are dirty (and most are) I recommend cleaning. I do not take a temperature drop on the unit if the coils are iced or dirty, as the reading will not be accurate.

I check most air ducts for air flow, using my hands only. Any poor air flow is noted.

In the attic, the air ducts are checked for insulation damage and for any possible leaks and improper installation.

All the above items are recorded and backed up with pictures.

Nice, but a lot of that is above and way beyond the SOP. If you test freon pressures etc then they will wonder why the air flow isn’t perfect on a room you only tested flow with your hand. Sounds far too detailed and surely time consuming. I assume you come from an HVAC background which is helpful but be careful not to lose opprotunity to test other parts of the house.
I often ask myself how I over checking or testing something will open liability as well. Its a balance of checking the ‘representative number of’ outlets or cupboard doors etc and looking like you checked 100% of something but if you don’t it looks like you are incompentent if you don’t.


The SOP is only a minimum standard, just like code is a minimum standard. I do not have an HVAC background. I do not test freon pressures, as you have to be licensed to perform that action. All of the above takes an extra 5 minutes to check, and is a quick way to determine ‘the condition’ of the system.

How many times have you had a system crap out on you shortly after the buyer has moved in. That simple test of the R.L.A has saved me many times by showing me that the compressor is pulling too much power. Now I can defer it over to a licensed HVAC contractor and not receive that dredded call that the system is not working. And especially now, after the new 13 SEER law is in effect, the price to replace these systems has increased.

How can you not report poor air flow in a room. It takes nothing to hold my hand up to the register and make a judgement of good, fair, or poor air flow. I also look at the ceilings around the registers for dirt, which is an indication of a poorly sealed duct.

With the price of an air conditioning system today, I would rather spend the extra 5 minutes on my inspection. As you all know, 90 percent of the time they need service anyway. This just create a better and more accurate picture of the system.

Please explain the RLA and FLA readings you take and how they help.
I thought you were taking freon pressures.

Poor air flow is important and I wasn’t complaining testing it. I do however feel it doesn’t mean a whole lot without some how determining the effectiveness of it. Might be fine in winter when you’re there but not summer for example. You’d have to set the environment to all sorts of conditions for it to really be meaningful but of course thats not practical.

I wasn’t suggesting to only stick to the SOP to the letter but was opening the discussion about the ‘respresetitive number’ issue.

Actually, it can be quite effective and, even in summer, can me very meaningful.

For example, I run the heating until everyone complains about how hot it is. Quite often, before they complain, they move from room to room trying to find one that’s cool. Now even in summer time, once they complain about hot how it is, then I’ve got them because if they call six months later during the winter months to complain, I simply ask them, “Were you the one who complained at the inspection about how hot it was and asked me if I could turn the heat off?” It usually is and they feel quite embarrassed at that point knowing that I’m not going to fall for their desire to have someone else (me!) pay for their troubles.

Once everyone complains about the heat, i.e., once they’re all “hot under the collar,” then I inform them that I always “heat them up and then cool them down,” so I’ll now be running the cooling system. I run it until everyone complains about how cold it is. Now, even in winter time, once they complain about how cold it is, then I’ve got them because if they call six months later during the summer months to complain, I simply ask them, “Were you the one who complained at the inspection about how cold it was and asked me if I could turn the air conditioner off?” It usually is and they feel quite embarrassed at that point knowing that I’m not going to fall for their desire to have someone else (me!) pay for their troubles.

Case closed for any issues between me and my Clients.

In one case four years ago, my Client had let the sellers live for four additional months in a rent-back situation without getting a deposit. So as soon as she moved in, yep, the cooling system didn’t work. My testing protocols worked perfectly. Ultimately, however, I helped her get a new air conditioner through the insurance company, they having initially declined to pay. It took a few letters to the insurance company and then a final leter to the California Commissioner of Corporations and the California Insurance Commissioner. Within a day of those two individuals getting my letters, my Client had a check in hand for a new air conditioner.