Hello All, I would appreciate your help in figuring out how to install a new heat pump t-stat. I'm just not up to racking my brain over it and need some input soon due to no air at the moment. The existing t-stat is a Total Line P374-0300 as found [URL="http://www.ntsupply.com/files/products/TotalineP374-0200.pdf"](HERE)[/URL]. It's a very inexpensive and basic t-stat. My unit is a two stage heat pump with auxiliary 10kw heat strip, btw. *The existing t-stat hookup is as follows: See image below... "W" = white wire "O" = green wire (#2). This is an apparent extra wire they used, so color maters not. "G" = green wire (#1) "R" = red wire "C" = blue wire "Y" = yellow wire *My new thermostat has 8 terminals as follows: It is a Honeywell RTHL2410C purchased at Lowes. "B" "O" "G" "Y" "W/Aux" "not used" "R" "Rc" There is a jumper between "R" and "Rc". Anyhow, my feeble mind tells me the existing red wire will go to "R/Rc", yellow wire will go to "Y", green wire(#1) will go to "G", white wire will go to "W/aux" for heat strip. That leaves the extra green wire(#2) and the blue wire left over. They apparently are used for "RVS Cooling" and "24 VAC Comm" as depicted in the image below? So where do those attach to the new t-stat?

Hi! I have an indoor blower that occasionally (maybe once per week) does not come on when it should, when the outdoor heat pump is running. When this happens: - Ice starts forming in the air handling unit - The outdoor unit is running, as it should (the setpoint is below the temp) - The G wire is at 24V - The Y wire is at 24v - If I switch fan from Auto to On, the fan still does not come on (but the G is still at 24v.) - The blower turns freely - The blower usually has been working just on the prior cycle (I sit next to the air handing unit most of the day and it comes on and off all day... then on one cycle, I just hear it start gurgling because the fan did not come on and the outside unit did....) - The control board inside the air handling unit does not show any signs of a blown anything If I then turn the thermostat to Off, the thermostat relays will shut off and the outdoor unit stops. If I then turn the thermostat back on.... it works.... even without delaying... The questions I have: Since the t-stat signals seem OK, would that indicate it is definitely NOT the t-stat? i.e. is the 24v on the green really the only significant thing in this case? What could possibly make it such that simply turning the thermostat to OFF then back on would correct the problem? I was thinking it was probably the control board in the air handling unit, but it does not make much sense to me that turning the t-stat off and back on would correct it. To the control board, that should look like a normal sequence. I have not been able to catch it and do the same test by upping the setpoint to turn off the outside unit that way - but suspect the same thing would happen. The air handling unit is a Carrier FC48NF024. The thermostat is a Hunter - dont have a model number but Im not thinking it is the problem anyway... Any ideas? And thanks in advance!