I bought a 2441TH 3 or 4 years ago and hooked it up a few days ago.  I did have it set up in the garage to turn on a heater in the winter using ISY.  It works fine.  I programmed it for its daily cycle.  It works as expected.  It is a little bit of an overkill as somebody is in the house 99% of the time.  Then I just had to go out on eBay and buy the wireless 2441ZTH.  My thought process here was have the wireless 2441ZTH in the office and run HVAC M-F 7 to 4.  The rest of the time the 2441TH would take over.  Back story about the office.  We work from home.  The office is the first drop from the HVAC.  The room gets the hottest of the heat and the coldest of the cold.  The office houses all our servers, routers, switches and the like.  The equipment goes into overheat, cool down mode when the office goes over 80.  It sounds like you are at the airport when this happens.  Now for the wife, she is freezing when it gets around 76.  That gives me a 4 degree spread between overheating servers and a freezing wife.  So I figured this remote device would keep the temp in the office more stable.  I set up the 2441ZTH in the office and paired it with the main 2441TH.  All seems to work.

The first problem here is I can't switch the "Master" buttons through ISY.  The option is not available in ISY (not that I can find).  I may have to live by doing it manually.

The second is I can't seem to enter program mode to program daily cycles like I did on the main unit.  Page 8 of the manual. I can press and hold program till I am blue in the face.  It will not enter program mode.  The instructions as I understand them says it needs to be plugged into a 5 volt source.  I have done that.  I have tied 5 vols, no volts, program while it is in master mode and when it is not in master mode.

Anybody done anything like this?

Could it be related to the second statement from the manual:

 

IMPORTANT! Day Modes only function when the Insteon Wireless Thermostat is connected to the
optional power adapter. Once you have added Insteon Wireless Thermostat to a scene in Insteon
Thermostat as a wireless temperature zone, the Program button will no longer function. All program
controls will be performed on the Insteon Thermostat.

@tmorse305Yes, I read that.  Very confusing.  It is connected to a power adapter and it is not added to a scene.  Neither of the thermostats are added to a scene. The wirless was brand new.  ???  Maybe I need to do a factory rest on it?  What is more puzzling, when the wirless is set to Master and in Day Mode, it runs in day mode.  I can see this by it using what I beleive are the default vales which are similar to mine.  I can't verify it as I can't get into program mode.

 

1 hour ago, CPrince said:

I set up the 2441ZTH in the office and paired it with the main 2441TH.

@CPrince, How did you pair them?  Using ISY or just device to device?  Maybe that pairing is enough to disable the wireless programming?  Try a factory reset and then see if you can program the wireless thermostat before you pair it with the main one.