Troubleshooting Guide - Honeywell MAGIC STAT MS3000 Owner's Manual

TROUBLESHOOTING GUIDE

IF...
Thermostat loses program.
Thermostat shows no display,
unless HEAT or COOL key is held.
Troubleshooting Guide continued
IF...
Display goes blank less than 30
seconds before or after a furnace
burn cycle.
Display goes blank for several
minutes during a long furnace burn
cycle.
Temperature display is incorrect.
Troubleshooting Guide continued
IF...
Furnace or air conditioner
operates continuously.
Thermostat will not turn heat or
air conditioner on.
Thermostat will not let you make
a temperature setting.
THEN...
Check for loose battery.
Check that power switch is ON.
Check that power switch is ON.
•l Check main switches, fuse and circuit breakers
on heating equipment to make sure the thermostat
has power. The heating control circuit powers the
thermostat even when it is controlling air condition-
ing equipment.
Check the wiring connections to the thermostat.
Make sure your system uses 24 Vat. The
thermostat will not operate on a millivolt system.
Jumper RC & Y or RH & W. If system comes on,
thermostat needs replacement. If system does not
come on, a problem exists in the system (such as
transformer, relay or valve).
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THEN...
Your furnace is interrupting power to the
thermostat. This is not a problem, as the 9 V
alkaline battery will be adequate to carry the
program for the entire heating season. Do NOT
use a rechargeable battery.
Check for dirty air filters or blocked registers. If
registers are not blocked and the air filter is clean,
an isolating relay probably needs to be installed on
your heating system. See Table 1 in the installation
manual, form number 69-8025.
•l See "Recalibrating the Thermostat," page 29.
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THEN...
Check the thermostat to see if it is wired properly.
Check the furnace and air conditioning systems to
make sure they are operating correctly.
•l Check circuk breaker on heater or air conditioner
to make sure it has power.
Check that pilot light/power is on; this thermostat
"steals" power from the heating circuit.
Verify wiring.
Check if you have already made 6 settings. A
maximum of 6 settings per day are available. The
thermostat will not accept a seventh setting.
Check if you have used all 8 available temperature
combinations. A maximum of 8 heating and cooling
combinations are allowed in total in your weekly
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69-8026—2