Honeywell MagicStat 28 Programming And Installation Instructions page 19

First, turn both screws in completely, then adjust for system type:
• Warm Air Furnace—Set at the Hot Water setting (A - out one turn, B - in).
• Electric Furnace—Leave at the Warm Air Furnace setting (A - in, B - in).
NOTE: This thermostat does not have a
setting for steam/gravity air. Cycles
would not be long enough for accurate
temperature control.
IMPORTANT
When using a high efficiency
furnace such as a 90 percent or
greater AFUE (Average Fuel
Utilization Efficiency) unit, adjust
screw A OUT ONE TURN and
screw B IN.
THERMOSTAT BACK
FOR HIGH EFFICIENCY FURNACE (90%+ AFUE)
ADJUST:
SCREW A–OUT 1 TURN
SCREW B–IN
FUEL SWITCH – F POSITION
FUEL SWITCH
F
17
A C
ADJUST SCREWS THROUGH HOLES
TO SELECT OPERATION DESIRED
HEATING SYSTEM
WARM AIR
A–IN B–IN
B D
FURNACE
HOT WATER A–OUT
B–IN
BOILER 1 TURN
ELECTRIC B–OUT
A–IN
FURNACE 1 TURN
W Y
E
R
INSTALLATION
FUEL SWITCH
POSITION
F
F
E
G
Rc
M3669