A week ago I had my 15 year old Carrier heat pump replaced with an Infinity heat pump (3 ton, 15 SEER).
I have the controller programmed for two time periods.
6 am- 78°
9 pm- 72°
Since a day or so after installation, early evening about 7 pm or so the "Cool At" temperature, which is the target setpoint, changes itself from 78° to some other number. I have seen it at 74°, 75°, 76°, and 77°. When I look at the program, the set point is still 78°.
On Tuesday I called the contractor. That afternoon they sent out a young man to look at the controller, and he could not find anything wrong. It happened again Tuesday evening and again last night. I called this morning and they sent out the man that installed the system (they have very responsive service, I am very pleased).
He spent about 30 minutes playing with the controller, making calls to his office, reading my manual, going to his truck, etc. Eventually he told me that the controller was acting normally, in that it was anticipating the 72° requirement at 9 pm. He told me that the system wanted to already be at the desired temperature at the time it was programmed for. Therefore, it started cooling down before 9 pm so that at 9 pm it was at 72°.
I have never heard of a system working like that, so I am somewhat skeptical. Is what he told me accurate?
If so, can I override that part of the system? We don't want the temperature to cool off before 9 pm. Should I set the time back to say, 11 pm, so that it starts cooling down later.
As always, thank you in advance for your assistance.
I think it's called intellligent recovery and the system ajust it'self to hit your set point at 9 pm. he is not bullpooping you. You may be able to disable it witout the installers manual. Read the owners manual first. If it doesnt work call and ask installer to return with installers manual to reset stat.
No bull. This is a well-documented feature that has been present in lots of nice programmable thermostats from many manufacturers for years, not just the Infinity. At least they figured it out eventually. They shouldn't have needed multiple visits to answer this question, though.
You don't program an Infinity system for when you want it to start heading for a given temperature. You tell it what time you want it to *achieve* a given temperature, and it will start at whatever time is right to arrive at that temperature at the appointed time. My Infinity system at home does this, and I like it that way.
So it understands your setting as "achieve 72 degrees by 9pm". It actually learns from experience how long it will take to change the temperature, given your house, your equipment, your conditions, etc., so that it starts at the right time (up to 90 minutes in advance). I really like the feature. With an old-fashioned programmable thermostat, the user had to guesstimate how long the system would take to achieve the temperature they should I set the air conditioner to start so that the house won't be hot when I get home?" The answer always depended on the weather, so the right answer in June doesn't work in August.
You can either work with the feature, by changing the time you specify for it to arrive at a certain temperature, or you can have your contractor turn off the Smart Recovery feature (that's what Carrier calls it). Then it will treat your program as "at 9pm, start heading for 72". Doing so will not be good for your heating efficiency, though. This feature is what lets the system recover from heating setback periods with the best energy efficiency. It minimizes the use of auxiliary heat while recovering from the setback period- that's why the thermostat setpoint moves along one degree at a time. You see the same thing on the display in cooling mode, even though it doesn't really have a similar effect.
Since from what you're saying it sounds like you might only want to defeat this function in cooling season, you might want to try adding more time periods to your cooling program. I'm not sure (never tried it) but I bet if you have another period at 8:30 pm, 78 degrees, it wouldn't start heading for 72 until 8:30, at least.
[Edited by wyounger on 10-13-2005 at 02:44 PM]
Yeah, you beat me to it. That was my thoughts too. I have put an additional time period in 30 minutes before on other brand product and it worked out. I am thinking it would here, but I haven't had any field experience with the Infinity system, just the training.
I noticed the same phenomenon on my new Infinity. It's good to know that's normal.
Thanks for all the replies and help. I will add another period at 8:30, and I am confident this will take care of the issue.
Chris: See if the installer will come out and shut off the Smart Recovery system on you Infinity thermostat. Instead of you having to remember to always be setting times up to 1-1/2 hours different than when you want things to happen...
It will take the guy about...20 seconds to do this...