Honeywell THM5421R1021 IAQ Equipment Interface Module

Product Information

It features three sets of universal IAQ contacts to control humidification, dehumidification and ventilation. The Honeywell Prestige 2-Wire IAQ Equipment Interface Module delivers easy, reliable connection to your home HVAC system.

My current setup behind the thermostat wall, there are 5 wires but only 3 are used by Honeywell thermostat (label as 1,2,3). Sorry, but I'm new to this forum and I couldn't figure out how to do a post other than to reply to this thread.Please let me know if you have other questions or concerns as I will be locking this in 24 hours if I won't hear back from you again. Everything seemed to work fine so as others have stated there is no problem having both the batteries and the 24v connected at the same time. The Equipment Interface Module controls up to 4-stages of heat and 2-stages of cool in a heat pump system and up to 3-stages of heat and 2-stages of cool in a conventional system. We make it easy and affordable for professionals and homeowners alike to find discounted air conditioning parts and wholesale heating system supplies. If my 24v goes dead then the furnace isn't going to run anyway even if my thermostat is still functional.

My current Honeywell visionPRO IAQ (TH9421C1004) thermostat is not working as the touchscreen is somewhat dead and unresponsive. I'm not impressed by honeywell either as I have written to them several times and I never get any responce. Honeywell is the backbone of the HVAC industry, helping to improve the lives of consumers by providing innovative, cutting-edge solutions.The problem was he had attached the wire to the RC terminal which was jumpered to the R terminal but he had not tightened the screw connecting the jumper wire to the R terminal. Famous can help you with specifications, product options, design, layout, and coordination of your project from A to Z. Still it could well be that this lithium battery keeps the programming intact also and the alkaline batteries power the communications, I don't know.

Right now there are absolutly no wires connected between the stat and the furnace or the equipment interface module. Operating Temperature Rating -40 to 165 Deg F; Supply Voltage 18 to 30 VAC; Current Rating 1 Amp (Cool), 1 Amp (Heat), 0. They are also powering the totally wireless communication betweem my stat and the furnace via the equipment interface module which is in turn hard wired to the furnace. Check with your company admin to get an invite to your company's profile, then create your own account.

I want to replace my Honeywell thermostat that is only connected using 3 wires; Red, White and green to a nest thermostat.