? for HVAC techs on Honeywell Thermostat

[CC]

Just had a new gas pack installed and the thermostat put in is a Honeywell T8600D 2069 Chronotherm !V Plus programmable thermostat The system works good and am happy with it, However, when the times are set for return and wake, The furnace comes on at least 1 1/4 hours before the time set. So it ends up the house is heated way longer than wanted. Is this normal or do I possibly have a thermostat that is defective or needs some adjustment? System replaced a gas pack installed in '89 and also had a programmable thermostat with it. It work without any problems and usually fired up the furnace very close to the time set. Thanks for any information in advance. CC

[Dr. Hardcrab]

The Chronoterms have "adaptive recovery". A round about way of explaining it:

If you have it set for "return" say at 5 pm, the furnace will come on and cycle before 5 o'clock in order for the house to be at the temp you selected for 5 pm. It may come on at 4, run for a few minutes, rest, then come on again, and so on unitl it reaches the temperature you selected. I know it sounds hokie, but sometimes it takes a couple of weeks for your thermostat to "get used to" you house. They really do have a "brain" in it that will eventually adjust to how fast or slow your house heats up or cools down.

When you say it comes on 1 1/4 hours beforehand, it probably doesn't run constantly, but cycles.

Give it a couple of weeks. It's will smooth out the "wrinkles".....

[Dick]

You can also over-ride the adaptive recovery so that the Chronotherm runs like a regular thermostat. That's the way we have ours set. We want the house to start warming up at 7:00 A.M., but don't want the heat on before that. With our new Trane dual-fuel heat pump it only takes a few minutes to get from 65 to 72-degrees in the morning.

You will have to read the Installer's Guide for the Chronotherm, not the Owner's guide, to see how to change it from adaptive to conventional. Hopefully, the installer left it with you. You have to get into the programming menu. For ours, it's menu item 13, but yours may be different. These Chronotherms are like little computers.

[Bob]

The way Honeywell explained Adaptive Intelligent Recovery to me years ago, was that the thermostat remembers how long it takes to get up to temperature during the previous 4 days and averages it out.

[Dick]

Apparently, it is different now. The manual explain, "When calculating the time to turn on your heating or cooling system, it considers (1) air temperature, (2) wall temperature, and (3) the time you want to reach the comfort temperature."

[Bob]

Yea, and you can program the maximum heat temp so people can't raise the temp over that. You can also set the thermostat to read a different temperature than it really is.

[Bob]

[Joseph Meehan]

Give it a few days to get to know your home. It is designed to figure out how long it takes you home to warm up. It then will start warming it up sooner on a cold night and later on a less cold night. With it turned off, you would need to set the higher temperature to come on some unknown time before you wanted it that warm.

I have it and I do like it.

BTW be sure the thermostat has the correct time set. :-)

[cornytheclown]

evaporator coil.....sounds like its leaking....

[CC]

[barry]

And ... you can delay the setpoint, if all else fails. Instead of 5pm, say, make it 7pm.

That sort of thing works with mine, so on arriving home there's still some useful work left for the woodstove to do.

J

[CC]

I've been working on moving the times to a later period than I actually want it to come on. Am off the rest of the week so I will be able to observe when it actually cycles on as to what I really want it to be. Will also watch to see if it adjusts itself to changes in the temperature of the house as the week goes on. Thanks cc