Vision Pro Thermostat Operation Questions
I have a two stage Honeywell Vision Pro Thermostat, Model TB8220U that is connected to my American Standard two stage high efficiency furnace. It is programmed with the adaptive recovery option turned on. Overall, I like the thermostat and the display is certainly easy to read and use.
I've noticed the following quirks:
- Even when the outdoor temperature is consistently COLD for several days, the thermostat seems to miss its target because it starts the recovery mode about two hours prior to the target time. In other words, it doesn't seem to adapt to the increased time needed. I don't have an outdoor temperature sensor, but I remember reading that the thermostat only uses an outdoor sensor in its calculations when it is used for Heat Pumps, is this correct? (Option 340). It would be convenient to see the outdoor temperature on the screen though.
- What is the difference between Option 680 "Temperature Control Heat" (Less Aggressive, Standard, More Aggressive) and Option 685 "Recovery Heat Ramp Rate" (Degrees per Hour)? Degrees per hour sounds pretty self explanatory but I'm not sure what aggressive temperature control is.
I've noticed that the furnace will go into recovery mode, at some point will ramp up to Stage 2, then slow down, then turn off, then repeat the process, all during the recovery time. ("Recovery" is displayed). Unless the outdoor temperature became much warmer (it hasn't), why does the thermostat use stage 1 unless it learns that it's going to need more heat to reach the target on time?
- If the displayed temperature is within 1 degree of the set temperature (including the old temperature if it is recovering), the thermostat displays the set temperature as the current temperature. For example, if it is a constant 68 room temperature and I set the thermostat to 69 degrees, exactly two minutes after I do this, the displayed temperature will also change to 69 even if the furnace didn't turn on. Turn it back down to 68 and exactly 120 seconds later 68 degrees will be displayed again too. I would much rather the display to be accurate instead of changing to make me feel better. Is there any way to disable this "feature?"
- If setback time is 11:00 PM, the thermostat may still turn the furnace on at 10:58 only to shut it off a minute later with no real heat added to the house. Why doesn't the adaptive thermostat realize that the set temp is about to go down and short cycling the furnace is pointless?
- The thermostat has daylight savings (Option 330), but was purchased just before the dates were changed by the government. I know later models have the new dates, is there anyway to add this to an existing thermostat? Honeywell wouldn't say much.
Are long cycles better for the furnace longevity than shorter cycles? Does the igniter's expected lifetime decrease each time it is used? What is the best combination of settings 680, 685, (others?) for longer cycles?
Thank you very much!
Yes, the outdoor sensor is only used for controlling heat pumps.
680 effects any type of heating system.
685 is only useable with heat pumps, and monitors temp increase by time.
That display glitch, has been in them since they first came out, and there is no way to over ride it.
Some of the older versions, did indeed keep the heat off. But, it would allow the temp to drop too much.
Many people didn’t like it, because it would get cool.
At this time, as far as I know, no update can be made to the DST feature (congress still hasn‘t made the new DST permanent).
Longer run times are less wear and tear on the furnace, since starting a motor is harder then keeping it running.
An aggressive setting takes care of most not meeting set temp recovery problems.
make sure you did not turn the adaptive intellegence setting to off
My install instructions don't mention a 685 (goes from 680 to 690), and my T-stat doesn't have it either (and yup, I've got a heat pump).
Originally Posted by beenthere
But, do you have a TB8220U commercial thermostat.
Originally Posted by rcamner
Or a residential TH8320 thermostat.
They are not the same.
Bet you don't have 0695-Recovery cool ramp rate(0-20° an hour), either.
Honeywell has a lot of thermostat model numbers that are close to each other.
But, the stats are worlds apart as far as what they can do.
There is nothing more frightful than ignorance in action....Mark Twain
Neither! I pulled the thermostat off the base, and the model # is TH9421C1004. Any particular significance to that of which I should be aware?
Originally Posted by beenthere
You have the Honeywell IAQ thermostat.
It has a lot better control of the equipment then a TH8320 has.
But still doesn't have the same settings as the commercial stat the OP has.
Significance you should be aware of? Depends on what equipment its connected to.
Thanks. It's connected to a American Standard Heritage 16 2 stage HP and a Am. Std. 2 stage gas furnace.
See answer in other post.