Ask Experts Questions for FREE Help !
Ask
    melburstein's Avatar
    melburstein Posts: 1, Reputation: 1
    New Member
    		  
    #1

    Nov 22, 2009, 12:22 PM
    HVAC Thermostat Blacks out
    A HVAC tech just replaced our Compressor, Coil and Furnace (brand new Carrier units). We are seeing the same problem that we experienced for three years with our old system. While the furnace is running, for reasons we don't understand, the thermostat suddenly blacks out. The furnace continues to run but we can not make any adjustments because the thermostat display is blank. After a short period the Thermostat again begins to display and access to all functions returns.

    This has happened with three different thermostats and two different furnaces. What can the problem be?
    KC13's Avatar
    KC13 Posts: 2,556, Reputation: 99
    Ultra Member
    		  
    #2

    Nov 22, 2009, 12:35 PM

    If the furnace is overheating, the main limit control will interrupt low voltage control power until it cools and resets. Look for a status LED behind a clear viewer disc on the front panel or blower access panel. Clues are there. If blinking while t-stat display is blank, observe and note pattern. Look for service legend inside access panels or on circuit board for description of status being displayed.
Not your question? Ask your question View similar questions
 

Question Tools Search this Question
Search this Question:

Advanced Search

Add your answer here.


Check out some similar questions!

Totaline P374-1000 HVAC Thermostat [ 1 Answers ]

The Thermostat goes blank most of the time. Have to pull it off the base and replace it to make it work. Wires in the back have a good connection. There is low voltage coming in to the wires. Where is the battery for the unit located at? Could not find one internally. Once the heating went on...

Hvac not working after changing thermostat [ 1 Answers ]

A house I am purchasing had central AC working fine before. However, after the home inspector played around with the thermostat the system did not work. I replaced the thermostat because the thermostat panel no longer lit up. I replaced it with a programmable thermostat, being careful to...

Hvac Thermostat Replacement [ 2 Answers ]

How may I replace a old thermostat if it does not have wire label, it has four wires ( red, green, orange and white. The new Thermostat model RTH221B Honeywell, Thanks

Hvac thermostat [ 1 Answers ]

Need to know the wire color thermostat replacement from trane1000 to honeywell 3100c

Hvac thermostat [ 3 Answers ]

I put a new thermostat in and the ac works right but the furnace won't fire up

View more questions Search