http://www.hvac-talk.com/vbb/showthread.php?t=175023

Had my new HVAC system installed Thursday and I have a question about the install of the IAQ. System is Lennox XC16-048 with Lennox G60UHV-60C-090X a five-ton Aspen coil and IAQ t-stat (based on suggestions from above linked thread).

The installer had never put in an IAQ before and spent quite some time perusing the install manual and calling his shop as he wired it up. I see he put in the R > DHM1 jumper like the manual says, but there is no wire from the IAQ module DHM2 connection to the furnace and it looks to me in the manual like there should be one. Figure 16 in the IAQ manual says DHM2 wire goes to "low speed fan" on the furnace, but the installer could not find a connection on the furnace for "low speed fan." From the way I read the furnace install manual it looks like the "DS" connection on the furnace is where the IAQ DHM2 wire should go... is this correct?

Also, shouldn't jumper W914 on the furnace board be cut to allow the IAQ to run things?

I called the company yesterday and they are sending a senior tech out Monday to take a look, but given the company's unfamiliarity with this t-stat I was hoping to help point him in the right direction. The tech on Monday is also supposed to go through all the IAQ installer setup to make sure it is correct (I already checked and it is not).

Would it be best to disable all the ramping profiles in the furnace dips and just let the IAQ handle all this?

The install company has been very responsive and is eager to try out this t-stat and make things right, but I am a little frustrated that the initial install tech just left all the furnace and IAQ settings at default and hit the road. For example, I see the W915 jumper on the furnace board was not cut, so the system is operating only on second stage. Also, I see a 5-4 trouble code flashing in the furnace that indicates reversed polarity and the heater does not work (I assume because of the reversed polarity).

Appreciate any advice.