Is this normal?

Anyone ever boil water over a fire in a paper cup?
NOTHING happens to the paper cup!
Nothing will happen to the evaporator coil either. There is refrigerant in there that absorbs the heat from the coil parts (just like the water (which is a refrigerant by the way)).

A/C air too cold for the furnace heat exchanger?
What temperature air passes through the heater in the winter? Almost the same as in the summer with the A/C on!

…** *It also should not be performed when a separate air-conditioning unit is on ***

We are the only Home Inspection firm that is a member of both

Staten Island Chamber of Commerce

Staten Island Board of Realtors! :roll:

Explain yourself…

Just quoting this book.

What makes it worth quoting?

I set up havc equipment in museum’s that run in A/C and Heat at the exact time to control humidity. The A/C has to keep running to remove humidity and it will get too cold unless the heat runs.

What do you call this?


Many digital thermostats have an “auto” setting. AUTO- stands for AUTOMATIC mode - the thermostat will call for the heat to turn on or the air conditioning to come on depending on the temperature set on the thermostat. For example if your thermostat is set to 68 degF and the room temperature drops below 68 degF the heat will come on. If temperature rises above 68 degF the cooling system will come on.

Jae, I would almost agree with you however the Section in the chapter of the book does not even mention a heat pump until later on where it is listed in the Air Conditioning chapter.

In either case…

my belief is the book is somewhat confusing in the way it is written and could be more clear.

I called the instructor of the licensing course to confirm what he had spoken about in his class. He confirmed that he did indeed say not to test both because that is how it would appear on the exam since the exam was based on the content of the book. He also confirmed that testing of the heat and a/c during the course of an inspection would likely not cause a problem as you and most others here have also confirmed.

With that said, I test both starting with tomorrow’s inspection.

Most thermostats I’ve seen have a switch or button for Heat or Cool mode, and a separate switch or button for fan operation as either AUTO or ON. And yes, I do know what AUTO stands for.

Good call, John.

Do all New York inspectors refuse to test the Furnace after the AC has been operating?

Odd, I live at about the same latitude and I test them.

It was ninety degrees outside today and yes I tested the furnace after the AC had been on for 3 hours.

See the pretty picture.

I just wanted to see how many inspectors would admit to not informing their clients they were about to buy a house with a worn out furnace. I may have coined that phrase about 40 years ago when I was a 10 yr old kid. No soft inspections here, when its slap worn out my clients know about it. :smiley:

In case you didn’t know, the professional HVAC techs are recommending replacement very often. I’ll let you do your homework and find out when and why.

Sorry, but no.
There is a “dead band” on either side of the set point temp (your 68 degF) that does not allow heat or cooling to occur.

During your promised in depth response, please include your opinion regarding the use of a boroscope to examine accessable portions of a heat exchanger. I have found some damaged exchangers using the Rigid See Snake.

Age in and of itself is not a defect, for equipment (except for smoke detectors) or people. Useful information for the buyer, but does not constitute a need for replacement in it’s own right.

“Slap wore out” in spite of it working fine might be a tough assessment to defend in court after the seller sues you. I’m curious, at what chronological age is a car “slap wore out”? We need to tell Jay Lenno his garage is full of old crap.

If you used the boroscope to inspect the heat exchanger and you missed a crack…and the client called you about it…would you pay for a new furnace out of your pocket, or would you try to fall back on the SOP for protection?

ohhh…that is a good one. I would say out of pocket. No SoP protection on that one.


I would never report that the exchanger was not cracked. I would document the extent of the inspection and what it revealed. Cracked heat exchangers cannot be found without total dismantling of the HVAC furnace. If they want me to pay for a new furnace, they have to let me take it all apart.

One service call $79.95, dismantle one furnace $902.

**Usually an indicator that the heat exchanger is cracked or perforated.
When blower comes on some of the combustion gases are pushed back out of the burner chamber. Eventually the leak will get large enough that not only combustion gases get pushed out flames will roll out.

As an HVAC Tech when I saw staining like that 99% of the time I would find cracks or perforations.

Write it up for an HVAC Co. to inspect.

getting a bit harder to do with high-efficiency equipment…