RCS Auto mode, how well does it work.

[pbibm]

I am using 2 RCS Bi directional stats, TX15B and TX10B; functionally the same for this discussion. Its winter in Michigan, so I am using Heat mode and have tried Auto mode, and they both do the same thing (heat) as I would expect them to.

I am wondering how auto mode works as spring gets closer, and how frequently the stat cycles back and forth between heat and cold when in auto mode. So, here are some questions...

1) Do you recommend using automode for seasons where the temperature frequently and rapidly moves above and below the setpoint? I am concerned it will go from heat to AC and back again many times in an individual day. The stat doesnt tell me exactly what it is doing (as opposed to how its set), short of trying to interpret setpoint and temp at the stat, and the power monitors i put in for the hvac system

2) What approaches have you used to deal with this kind of climate problem? As an example, I have an attic fan, and tiggering that with a combination of an outside temperature sensor might help trying to manually select heat and cool mode. Check the setpoint, check the temp at the stat, check the outside temperature. Program it so that it tries to cool (or heat) the house up using outside air.

3) Have you had any actual problems with this, or am I overthinking it and worrying too much, its a great feature and just let it do its thing. I am seeing now why that dual setpoint feature is useful, it probably addresses this to a great degree. I suppose a dual setpoint could be hacked with code.
Any thoughts greatly appreciated.

Thanks
Paul

[Msekelsky]

Hi Paul- I for one pretty much gave up on auto without even trying it. In my case I have my downstairs stat set to 72 for heat, but 75 for cool, so right off the bat the fact that not having seperate set points (not an issue for the txb16) means that I'd have cool at the wrong time.

Second issue, since I have two stats, is that I'd have days where the air would run upstairs and the heat may run downstairs. And finally, humidity. When the humditiy is low, like in early spring and late fall, I don't need the air much at all. BUt that same spring temp with summer humdity needs the air. So all in all I use the old fashioned manual method of setting the mode.

[pbibm]

Thanks mark, that confirmed what I was thinking too. I have two stats as well, one downstairs, and one up.

Outside humidity is a big factor for me too. If the outside temp is above a certain level, and the humidity is above a certain level, the air is goign on in both places. I will really get high WAF out of that.

I have been using your setpoint bounce method as well to control the 2 degree spacing, seems to work well. Ironically, my old honeywell stats triggered the cycles sooner than the RCS. I hung the rcs nearby the honeywell before connecting the RCS, and watched both to see which triggered Heat mode first. THe honeywell always won....

As an fyi, I trigger the 2 degree bounce mode using the furnace power montior. When the furance kicks off, I take that x10 "off" signal as the heat cyle being done, and set the new setpoint low. when I get the the x10 "on" signal from the power monitor, saying the cyle is started, I go ahead and set the set point high. Just a technique fyi

I havent forgotten my MeasureOntime util, I will finish that up as I get my stat coding completed and the first SMUG user meeting this Sunday.

Paul

[Msekelsky]

That's an interesting idea on the motor turing on/off, I'll have to give that some thought. Good luck with your first SMUG meeting. I have yet to make a Chicagoland meeting as I've had a conflict every time. I'm actually in town for their next meeting and *think* I may be able to make one.