Carrier thermostat manuals manualslib has more than 295 carrier thermostat manuals click on an alphabet below to see the full list of models starting with that letter. Appliance manuals and free pdf instructions find the user manual you need for your home appliance products and more at manualsonline. Hello i am replacing an old carrier mercury model thermostat with a non programmable cool heat honeywell ct31a thermostat the old thermostat was controlling air conditioning and electric heating through five connectors labeled y g w r and a mysterious a although near the unconnected 4 and without any jumper between them. Installation instructions connection of a carrier hrv or erv without the need for a separate wall control all system components are controlled through the wall mounted infinity control which replaces the conventional thermostat and provides the homeowner with a single wall control for all features of the system 2 installation start up