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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 5648
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Replaced batteries, but screen only shows the bottom five

Customer Question

replaced batteries, but screen only shows the bottom five squares when screen is pressed.
Submitted: 1 year ago.
Category: HVAC
Expert:  airheatman replied 1 year ago.

What is model on thermostat?

Customer: replied 1 year ago.
VisionPro TH8000 Series
Expert:  airheatman replied 1 year ago.

OK and you are getting no temp display or time?

Customer: replied 1 year ago.
I just see five squares at the bottom of screen, nothing else.
Customer: replied 1 year ago.
I am able to see you now online, So just type your answers instead of calling,
Customer: replied 1 year ago.
No temp display or time. Just the five squares at the bottom of the screen which has no content.
Expert:  airheatman replied 1 year ago.

Remove front of thermostat again and look real closely at the little prongs that plug in.Make sure they are all straight,none slightly bent

Customer: replied 1 year ago.
I will check the prongs once more
Expert:  airheatman replied 1 year ago.

If they all look good.Tell me if thermostat has a wire connected to C terminal and if you have a volt meter to check between R and C for 24 volts.

Customer: replied 1 year ago.
Prongs are not bent
Expert:  airheatman replied 1 year ago.

Tell me if thermostat has a wire connected to C terminal and if you have a volt meter to check between R and C for 24 volts.

Customer: replied 1 year ago.
I don't have a volt meter. I have the manual, where is the C Terminal?
Expert:  airheatman replied 1 year ago.

Bottom right, but not going to help probably if you don't have a meter.

Do you have another new set of batteries we can try?

Customer: replied 1 year ago.
but I bought a new package of batteries to replace the old ones.
Expert:  airheatman replied 1 year ago.

Did you try different ones already?

Customer: replied 1 year ago.
no, but I will. I checked the wires. A white, a red, and a yellow. They all look connected.
Customer: replied 1 year ago.
I changed the batteries. Nothing has changed.
Expert:  airheatman replied 1 year ago.

For unit to come on, we have to have power but the display actually come on and show temp even with front off and in your hand.Honeywell classifies this an arm chair programmable stat.In otherwords. you should be able to take it off the wall and go sit in your chair to program it and have all settings and numbers on display. If you have batteries that are definitely good, your thermostat has probably taken a power spike and will have to be replaced.

Expert:  airheatman replied 1 year ago.

There is one trick I have seen work to reset these digital thermostats that works sometimes. That is to remove batteries and install them backwards for 5 seconds, Then remove and install properly,If this does not reset the little computer board in the thermostat you will need to replace the thermostat.

Note: Occasionally , this will not work and will even cause thermostat to start smoking.If so simply remove batteries.If thermostat is not working already, it is worthless anyway, so no harm done .I have seen it work about 20 per cent of the time. So if that is something you are comfortable doing would try it.Could save you having to buy another thermostat.Otherwise, just go ahead and replace it.

Customer: replied 1 year ago.
I am not sure the thermostat is bad. It was working until I tried to change the batteries. I am thinking I should call my furnace person on Monday.
Expert:  airheatman replied 1 year ago.

I understand. If you have no display on thermostat with new batteries, you should have display though.Let me know what he finds.

Expert:  airheatman replied 1 year ago.

Are you 100 per cent sure batteries are installed correctly?

Customer: replied 1 year ago.
Expert:  airheatman replied 1 year ago.

Let me know what tech finds. Not much else we can troubleshoot.