Honeywell TH8320R1003 Vision Pro 8000 Product Data page 123

Fig. 320. Geothermal radiant heat with geothermal forced air and backup heat using separate transformer for the radiant
1 U1, U2 or U3 terminals must be used for geothermal radiant heat (ISU 201). Thermostat allows 2 stages of radiant heat—geo-
thermal (stage 1) and boiler (stage 2).
2 "U" terminals are normally open dry contacts when set up for geothermal radiant heat. You must install a field jumper if radiant
heat is powered by system transformer. Do NOT install a field jumper if radiant heat has its own transformer.
3 L/A terminal sends continuous output when thermostat is set to EM HEAT mode except when set up for Economizer or TOD. See
"Economizer Module Wiring Diagrams" beginning on page 131.
4 Y2 used with heat pumps that have 2 compressor stages.
NOTE: For setup and operation, see "Geothermal Radiant Heat" beginning on page 77.
THERMOSTAT/EIM
TO THERMOSTAT
FURNACE
HEAT PUMP
O/B
AUX1
AUX2
L/A
3
1
HEAT PUMP
O O
W1 Y
W2 Y2 4
Y
R
Y2 C
G
R
PUMP
C
RADIANT HEAT
ZONE MODULE
TRANSFORMER
C
24 120
VAC VAC
R
heat.
123
®
VISIONPRO 8000 WITH REDLINK™
VALVE
M34525
68-0312—01