DIYbanter - View Single Post - Delta method good enough to fail entire A/C system?

From: (ComboverFish)

Hello, experienced masses....

I am selling my home and have fixed everything that has been asked by
the prospective buyer and the city so far but am having difficulty
with the buyer's inspector in regard to his A/C performance spec.

The inspector told buyer that the temp drop from return vent to
evaporator test point was 10 degrees. The buyer was told that my A/C
system isn't performing as it should. I verified his finding of 10
degree drop after they left with MY thermometer. I'm not arguing his
number or his method. Please read on to see what I AM arguing about
(to myself).

The temperature outside at that time was only 75 F. and relative
humidity was 70%. This is a pretty cool day for St. Louis in July.
It was also overcast with virtually no sun. It was only 10 Oclock am
and with no sun load, the house was quite cool. My probe-style
thermometer read 68 degrees on my kitchen counter and in the return
air duct. I think its accurate within 1-2 degrees. I believe it to
be relatively accurate in terms of temperature differential, atleast.
So as stated previously, I put the thermometer in the same test point
as the inspector did with the system running and got 58 degrees. The
magic delta figure to fail a system and scare a buyer seems to be
below 15 - 17 degrees from what I've gathered in talking to realestate
agents and dealing with several home inspections. But don't you have
to take into consideration the temp and humidity and solar load to
some extent before interpreting delta temp?

I just happened to have an A/C company out two weeks ago to give my
system a performance test so I would be armed with a professional
opinion on paper before negotiations started. This is because the
previous owner had several big dogs, and apparently their big bladders
found the warm condenser fins a common target. (I was told that dogs'
urine is a common cause of condenser fin errosion). The missing fins
in one lower corner area coupled with some rust on the thin cage that
protects the condenser make the outside unit appear old and worn to be
sure. It isn't a great selling point visually. But this house isn't
the fricken' Taj Mahal either. I don't feel that someone can use the
APPEARANCE of my A/C unit to demand $2000+ for a new one IF IT WORKS!

The A/C guy I hired wrote that the temp change was 18 degrees,
pressures were normal and that 'system was operating normally at this
time'. It was about 85 degrees out and sunny that day and he did the
work around 2 pm. I tested the temp drop several days before he came
out and actually got 21 degrees but I can't remember the temperature
or sun condition then.

So how do you all feel about the accuracy of DELTA for the purposes of
condemning an A/C system? Do I really have a problem? Or may the
inspector have seen that the unit was around 15 - 20 years old with
fin damage and just found an easy way to condemn it that isn't
accurate? (much less than 5% fin damage)

I feel that for my 900 sq ft house with full basement (all cooled with
ductwork) and poor insulation my electric bills are reasonable. I
also feel that the A/C FEELS cold and the system has never been
charged in my 8 years here. I mean, 58 degree temp in the furnace
ductwork can't be that bad can it?

I thank you all for any responses yay or nay!!!

Tony

Why are you so worried? You fixed everything the city required. That's
different from the things the prospective buyers would LIKE you to fix for some
unknown deal where they've yet to tell you what they would LIKE to pay.

A simple "My asking price already takes that (the appearance and performance of
the unit) into consideration. You want a new unit? It'll raise the price. Lets
deal."

Or walk away.