Honeywell T8401C1015 Support Question
Honeywell T8401C1015 Support Question
Find answers below for this question about Honeywell T8401C1015 - Electronic Thermostat - 1 Heat/1Cool.Need a Honeywell T8401C1015 manual? We have 1 online manual for this item!
Question posted by avandor11 on October 29th, 2011
Thermostat Screen Is Blank And Won't Turn On The Ac Or Heater?
Thermostat screen is blank and does do anything. It does not turn on the ac or the heater?
Current Answers
Answer #1: Posted by pchelper on October 29th, 2011 4:49 PM
pchelper
Member since:
October 20th, 2011 Points: 206,890
Member since:
October 20th, 2011 Points: 206,890
First off do not panic. Second every time you switch the thermostat between AC, heat, or fan it takes a minimum of 5 minutes for your system to respond. Has it been five minutes? Not 5 seconds! The reasons is
The thermostat has a built-in five-minute delay on a request for air conditioning. This is for the purpose of protecting your air conditioning compressor from short cycling. This allows the pressure in your air conditioning compressor time to stabilize before starting. If your air conditioning has a built-in time delay as well, the two delays will run simultaneously
If this does not work after five minutes. Are there any codes on the screen? Is it blank? If it is blank then you need to do a hard reset and varies between manufacturers of the thermostats. There a link white rogers which is Sears and white rogers and the honeywell that usually 90 percent of home thermostats. If not then there is problem from anything from a bad wire to just resetting the furnace to replacing the thermostat would recommend the later as it will be the least expensive. The links below will help with that. Plus the information in the new manual.
The thermostat has a built-in five-minute delay on a request for air conditioning. This is for the purpose of protecting your air conditioning compressor from short cycling. This allows the pressure in your air conditioning compressor time to stabilize before starting. If your air conditioning has a built-in time delay as well, the two delays will run simultaneously
If this does not work after five minutes. Are there any codes on the screen? Is it blank? If it is blank then you need to do a hard reset and varies between manufacturers of the thermostats. There a link white rogers which is Sears and white rogers and the honeywell that usually 90 percent of home thermostats. If not then there is problem from anything from a bad wire to just resetting the furnace to replacing the thermostat would recommend the later as it will be the least expensive. The links below will help with that. Plus the information in the new manual.
Answer #2: Posted by dslant1 on February 24th, 2014 10:47 PM
dslant1
Member since:
February 24th, 2014 Points: 10
Member since:
February 24th, 2014 Points: 10
My Honeywell thermstat had a blank screen when the water pump stopped working. The thermostat controls a 95% efficient furnace. The water pump filled up and did not empty automatically. When I manually emptied the water tank in the pump the thermostat started working again. For a permanent fix the pump had to be replaced.
Related Honeywell T8401C1015 Manual Pages
Installation Instructions - Page 1
...-1740 T8400C, T8401C Electronic Thermostats
INSTALLATION INSTRUCTIONS
The T8400C and T8401C Thermostats provide singlestage, non-programmable temperature control for wiring and mounting thermostat) and owner's guide...wallplate, plug the hole to prevent drafts from heat to make sure the product is selectable at 1, 3, 4, 5, 6, 9, or 12 cph. Heating cycle rate is suitable for your old control ...
Installation Instructions - Page 2
... wraparound wiring connections;
NOTE: To ensure proper mounting of thermostat, restrict all wiring to wall.
Mounting wallplate to the shaded area.
either method is preset at the factory in a system where the G terminal is an electric heat system, set the switch to turn on immediately with local electrical codes and ordinances.
Setting Fan...
Installation Instructions - Page 3
...). TERMINAL SCREW
G
FOR STRAIGHT INSERTION STRIP 5/16 IN. (8 MM)
FOR WRAPAROUND STRIP 7/16 IN. (11 MM)
Rc R W Y
B
O
M13274
Fig. 5. T8400C, T8401C ELECTRONIC THERMOSTATS
KEEP WIRING IN SHADED AREA
G
Rc
R
W B
Y O
MOUNTING SCREW HOLE
WIRING ENTRANCE HOLE
MOUNTING SCREW HOLE
M16432
Fig. 4. M20880
Fig. 8. Typical hookup of T8400C in heat-cool system with single transformer.
Installation Instructions - Page 4
... runs continuously. M20882
Fig. 10.
FAN Switch
Fan switch settings are controlled manually by the heating equipment and may start a few minutes after the heating equipment turns on (on most homes.
T8400C, T8401C ELECTRONIC THERMOSTATS
G C
R
W
B
Y
O
1
L1
(HOT)
24V
L2
TRANSFORMER
HEAT RELAY
COOL RELAY
FAN RELAY
1 POWER SUPPLY. In cooling, the fan starts and stops with...
Installation Instructions - Page 5
... Room when the room temperature is on, ▼ key turns it on and off ; To set temperature setpoint: 1. M14684
System setting at HEAT: If heat is displayed in the bottom right corner of the thermostat to the desired mode.
INCREASE SETTING DECREASE SETTING
T8400C, T8401C ELECTRONIC THERMOSTATS
3. M14681
4. M14682
Set Room
AuFtAoNOn
FAN SWITCH
CoSoYl SOTffEMHeat...
Installation Instructions - Page 6
... the FAN switch to Auto.
2. When using an electric heat thermostat, the fan starts immediately.
3. Refer to raise the temperature setting several degrees below the room temperature. Slide the SYSTEM switch to Cool and the FAN switch to Auto.
2. T8400C, T8401C ELECTRONIC THERMOSTATS
NOTE:
In installer setup mode only, each press of the ▼...
Installation Instructions - Page 7
... minutes after the heating equipment turns on (on most systems).
Press the ▲ key to On. The fan should shut down. When using an electric heat thermostat, the fan starts and stops with the cooling equipment.
Be sure all equipment responds correctly to Auto. Cooling system should run continuously.
2. T8400C, T8401C ELECTRONIC THERMOSTATS
Fan
1. In cooling...
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