T8112D PROGRAMMABLE THERMOSTAT

68-0206 8
Home and Building Control
Honeywell Limited-Honeywell Limitée
155 Gordon Baker Road
North York, Ontario
M2H 3N7
68-0206 L.C. 2-98 Printed in U.S.A.
Home and Building Control
Honeywell Inc.
1985 Douglas Drive North
Golden Valley, MN 55422
Printed on recycled paper containing at
least 10% post-consumer paper fibers.

Minimum Off-Timer

A minimum off-timer for the T8112D assures that the cooling
compressor does not come on again for at least five minutes
after it turns off. The minimum-off timer is triggered when the
compressor turns off and when the system switch is changed.
If the compressor turns off when the setpoint is changed, then
the minimum-off timer is triggered, which operates only during
the cooling cycle of the T8112D.
TROUBLESHOOTING
www.honeywell.com/yourhome
IF… THEN…
Display will not come on. • Set the system switch to OFF; remove batteries; insert backward for at least
five seconds to reset thermostat; replace batteries correctly. Display should come
on.
• Make sure batteries are fresh and installed correctly.
Temperature display will not go lower
than 45°F (7°C) or higher than 88°F
(31°C) during programming.
• The temperature setting limit has been reached. The setting range is 45°F to 88°F
(7°C to 31°C).
Heating will not come on. • If the display is blank or displays
bAt Lo
, install fresh batteries.
• Check that the switch on the thermostat is set to HEAT.
• Check the system fuse or circuit breaker and replace or reset if necessary.
• If the temperature setting is higher than the current temperature, and SYSTEM ON
indicator is lit, see the furnace manufacturer instructions.
Cooling will not come on. • If the display is blank or displays
bAt Lo
, install fresh batteries.
• In 2- or 4-wire installations, verify that the R-Rc jumper is installed.
• Check that the switch on the thermostat is set to COOL.
• Check the system fuse or circuit breaker and replace or reset if necessary.
• The thermostat has a built-in time delay on cooling. Allow five to ten minutes after
changing the setting before the air conditioner starts.
• If the temperature setting is lower than the current temperature, and the SYSTEM
ON indicator is lit, see the air conditioner manufacturer instructions.
SYSTEM ON indicator is lit, but no
heat is coming from the registers. • Allow time for the furnace to heat up and the fan to come on before checking for
heat at the register. Check to make sure system on-time is set correctly according
to the instructions in the Installation section.
Furnace or air conditioner cycles too
frequently. • Readjust according to the instructions in the Installation Section.
The system on-time is too short or too
long. • Readjust according to the instructions in the Installation Section.
The thermostat current setting does
not match the display temperature. • Check that the wiring hole in the wall behind the wallplate was plugged with
insulation to prevent drafts that could adversely affect thermostat operation.
• It is normal for the current setting and display temperature to differ occasionally.
bAt Lo
remains on the display after
fresh batteries have been installed. • Remove batteries. Wait one hour. Install fresh alkaline batteries.