Here's the question. On the XC95m modulating furnace, what is the best thermostat selection? And if one already has the HW VP IAQ, what functionality on this furnace if any do I lose just keeping this thermostat?

thank you.

 

dont think ur gonna find a expert on trane modulating furnace in this forum, but if you explain what you want, maybe I or someone else can help. for instance: thermostat selection??? do you mean, temperature? brand? digital or non? if im correct in my assumption the modulating gas valve has dozens of micro settings in order to maintain a set limit, such as gas pressure and fan speed, am i right? also... Hw? vp? iaq? sorry for so many questions

 

I am a trane dealer. You should use the communicating t-stat from Trane. If you use the IAQ stat... depending if you have a conventional system, IE: no Heat Pump, you loose the modulation range and the system basically becomes a 3 stage furnace instead of a modulating. It still modulates, but at set parameters

 

hvactech

thank you for your reply.

yesterday, before I read your post, I called the local Trane distributor who has a residential specialist on staff and has always been a good resource on technical questions. here is what he told me.

while the XL900 stat is the preferred selection and gives you full modulation in 1% increments between 40-100% output, the IAQ can be used in full modulation as well just in 3% increments. he looked this up in a Trane bulletin. to me, that difference seems rather inconsequential.

however, I have to admit I don't have a warm fuzzy feeling about this. I should have asked him to mail or email me a copy of the bulletin. perhaps, I will call him back today.

BTW, this furnace will be paired with 15 SEER heat pump, ie dual fuel system.

what do you think?

thanks for reading and any other thoughts you might have.

 

My personal feeling is that I own and use the IAQ and love that t-stat.

 

I'd rather see the full modulating, but our winters are colder/longer than yours.

I have the IAQ, and love it as well.