Blue light on thermostat is faint on carrier infinity series

Most furnace operating on Oil or gas will heat the combustion chamber before starting fan to prevent cold air draft at start-up, can last a minute or two. Eiter the main flame does not come on or the chamber thermostat have fail. Try to modify fan option on room thermostat from auto to on. Cold air coming out: burner problem or no more oil or gas, warm air: burning chamber thermostat problem, leave room thermostat fan option to on until repair.

Sounds like you have the thermostat fan switch in the "ON" position instead of "AUTO". Give that a try. Beyond that you could have a thermostat thats wired wrong or an outright bad thermostat. Its difficult to go any further without knowing what type of furnace and thermostat you have. I hope this helps though. Good Luck.

Carrier Infinity system is a variable speed unit that will just slow down as it approaches set point. Unless it overshoots the set temperature (you have it set on 72 and the temperature keeps rising above 72) this just sounds like normal operation.

is the ac a manual one or automatic? if it's manual then it froze and will no longer work. it froze and is all done working. time for a new one. I bought one 12 years ago and apparently I was suppose to turn on and off. The ac couldn't do that. IF it works on it's own maybe the circuit isn't the higher amp for 220 ac units.

Let see if I can help. The numbers don't come up so we'll just try your information.

Exhaust - should be closed when using for Air Conditioning
Energy savings turns the fan off with the compressor when set for Air Conditioning
Fan Only means just that (no Air Conditioning)
Fan speeds Quite same as low, Norm same as medium, Super same as High
Temp settings, what the thermostat senses before cycling compressor.

check power to outside unit, check if it has a fused disconnect, if you have power and no blown fuses it could be a blown capicator that starts the fan and compressor...............

HI. There are a few areas i would advise to check to resolve this issue.

The dryer uses multiple thermostats to regulate the temperature. When the temperature is higher than the preset limit of a particular thermostat, the thermostat breaks the circuit and the heater goes off. When the temperature cools enough, the thermostat closes the circuit again and the heat can come on.



Most dryers have a choice of temperature settings, therefore a separate thermostat is used for each setting. The selector switch or timer control then routes the circuit through the appropriate thermostat.

If a thermostat fails, it may prevent the heat from coming on, This happens because the thermostat does not close the circuit when the temperature falls below the operating temperature of the switch. It is a simple matter to test a thermostat; it should show continuity when the switch is cool and no continuity when it is warmer than its rated temperature.

A thermostat can also fail by being always on, no matter what the temperature. This switch would show continuity whether it was hot or cold. In this case, the heater would not shut off and the the dryer could dangerously overheat. As a safety precaution a second thermostat is used, This is called a thermal fuse. The power will be cut to the heating circuit if the maximum safe temperature is exceeded. In most cases, this is a one time fuse. The heater circuit will not function until the fuse has been replaced. Of course, it will be necessary to determine and repair the underlying cause of overheating or the fuse will just cut out again.

The thermostats are usually grouped together. The are typically oval in shape and about an inch and a half in size. They may be on the blower housing, under the lint trap or inside the vent line. There should be two wires connected to each thermostat.

Label the wires and connections so that you can properly reconnect them later. The wires are connected with slip on connectors. Firmly pull the connectors off of the terminals. You may need to use a pair of needle-nose pliers to remove the connectors. Inspect the connectors and the terminals for corrosion. If either is corroded they should be cleaned or replaced.

To test the thermostats or fuse, set the multimeter to the ohms setting X1. Touch one probe to each terminal. You should get a reading of either zero or infinity. At room temperature, the thermostats should have a reading of zero. When the thermostats are heated to their limit temperature, they should switch off and you should get a reading of infinity. The fuse should be tested at room temperature for continuity.

NOTE(If the Thermostats and fuse check out ok, replace the element. Element failure is uncommon but, it may fail in certain cases))

(Make sure the entire venting assembly is not clogged as well)

Verify 24 volts at the low voltage transformer inside the air handler. If it is OK, jump out the red/green and yellow thermostat wires. If everything comes on, replace the thermostat.

I had the same problem with my 96 Nissan/ infinity g20.
If I turned on the ac the brake & battery lights came on, the AC fan would work but the air did not blow cold. Disconnected the battery for a few hours to reset the computer. That solved the problem.
Now, no lights, and the AC blows cold.

Your old stat is wired for a traditional thermostat and not a communication stat like the new infinity you have. There is a module plug on the furnace board that will need to be connected to the new thermostat for it to work. The wires that are wired now are from a terminal strip inside the furnace. Please contact your local Carrier dealer. They may be able to get that harness for you