Jeff and Beth wrote:

We seem to be having an odd problem with our heat pump/HVAC system.
As temperatures here have recently (finally) climbed into the mid to
upper 60s, our house heated itself up to about 78 degrees (per the
thermostat reading). The thermostat was set on "heat" and set to 72.
As the 78 degrees in the house was pretty warm last night, I went to
set the thermostat to "cool". I noticed the thermostat was flashing
to "replace batteries". I did so. I then set the thermostat to
"cool" and to 73 degrees. This morning the temperature still read 78.

This evening I'm fighting the same battle. The termperature inside
has actually gone UP to 79. Thermostat still set to cool. I checked
to verify that the heat pump outside has kicked on and it has.

The heat pump was replaced in 2001 and the inside system in 1999.
Could this be a switch sticking and not cliking over from "heat" to
"cool"? Does the system take time to move from heat to cool? I don't
remember this from past years, but I also don't rememeber big early
March temp swings from 20 to 70 in just a few days (though I'm sure
they happened). Could this be a weird result of the thermostat
batteris frittering out before we replaced them? Could this be a
freon issue? I'd like to get some level of education on this before
inviting the HVAC guys out to the house to explain how this is going
to cost me some hundreds of dollars.

After I originally posted this in alt.hvac last night, I noticed
something else that happened overnight. I turned off the system
alotgether since the outside temps were supposed to be right around 50
degrees overnight. The house is still 78 degrees inside even this
morning. I have a regular store bought thermometer sitting on top of
the thermostat just to doublecheck. I know there's probably some
physics lesson out there that could help explain, but I'm curious as
to why the house is hanging on at 78 with no mechanical intervention
even though it's never gotten that warm outside. Maybe the heat pump
wasn't warming the house, but it just wasn't cooling it either.....

Thanks very much for any help.

jeff
you probably have heat coming from yours and others body.. the heat from
cooking, the heat from the attic filtering down into the rooms...and any
appliance thats plugged in including the computer/tv etc... most of the
time in the south we dont need any heat at all...at night the temp. goes
down to 55 or so and in the day around noon its about 75 to 80 degrees
the last couple of days.. i gotta turn the a/c on to about 75 to just
get the a/c to come on... it will cool the house down, but at 78 or 79
it does not come on and the house feels warm.....if i read your post
correctly its probably just the variable of what hot and cold to you???
and we always have to ask who put the themostat to 80 or 85??? someone
always turns it up if they feel cold when coming out of th bath after
taking a shower... and no one ever claims that they did that.. well i
know my thermostat does not chang itself.... with a house full of kids
it must be the ghost or something that is doing it????