If my 24v goes dead then the furnace isn't going to run anyway even if my thermostat is still functional. The THM5421R1021 interface module streamlines the performance of the system helping clients reduce energy costs. Applications include Gas, oil, electric, heat pump, forced warm air, hot water, steam or gravity systems. To learn about our use of cookies and how you can manage your cookie settings, please see our Cookie Policy. Thinking, I may have a defective unit, I exchanged it -- but now the replacement is doing the same thing.

Gas, Oil, Electric, Heat Pump, Forced Warm Air, Hot Water, Steam Or Gravity Application, Up To 3 Heat 2 Cool Heat Pump Or Up To 2 Heat 2 Cool Conventional Stages, For Use With Wireless FocusPRO Thermostats. 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. Hardwired is best, I usually do both for no reason really other than the batteries come in the box so I put them in.I suspect most installers and homeowners will be mostly concerned with how to install the equipment properly and less with the engineering details about how the electronics actually work. You can change your choices at any time by visiting Cookie preferences, as described in the Cookie notice. Understanding the importance of quality and reliability, we supply an extensive selection of energy-efficient heating equipment for sale, as well as energy-efficient HVAC equipment designed to elevate the functionality and efficiency of existing systems. Styles from transitional to modern and traditional, you can count on Craft33 cabinets to compliment your clients’ lifestyle and budget. My new thermostat booted and I was able to pair it with an in-house and an outside sensors with ease.

If you have any problems with the registration process or your account login, please contact support. My current Honeywell visionPRO IAQ (TH9421C1004) thermostat is not working as the touchscreen is somewhat dead and unresponsive.With 31 Famous Supply locations in Ohio, western Pennsylvania, and West Virginia, your local Famous counter has everything you need to help you get your project done. It looks like we can consider this one complete, so I will lock the thread shortly unless I can help out with anything else. We don’t share your credit card details with third-party sellers, and we don’t sell your information to others.

These facts led me to worry that connecting both at the same time might be incorrect and damage my stat. This statement makes me think that both the 24VAC and the batteries can be connected at the same time because of the backup reference, but I'm not sure. I kept the red wire where it was, but switched the white wire from the W to C-terminal on the thermostat and to the "common" terminal in the boiler room (inside a TACO 406 ZVC). Highly compatible with the Honeywell Prestige IAQ System, the THM5421R1021 module saves you time and money. Then you'll be able to select which homeowners see your logo based on the pricing per household (consumer will not be charged).This lightweight and highly reliable Equipment Interface Module comes with a UPC code of 085267328180. I'm not impressed by honeywell either as I have written to them several times and I never get any responce. Our old heat-only thermostat had exactly two wires running to it from the boiler room: red and white (connected to the R and W terminals respectively). Operating Temperature Rating -40 to 165 Deg F; Supply Voltage 18 to 30 VAC; Current Rating 1 Amp (Cool), 1 Amp (Heat), 0.

Famous can help you with specifications, product options, design, layout, and coordination of your project from A to Z.As long as I know other installers have conected both the batteries and the 24V at the same time without causing any damage, then for me this issue is laid to rest.