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Sequence of Operation
Section A
General
Operation
Page 4 - 5
Section B
Mixing
Reset
Page 5 - 8
Section C
Boiler
Operation
Page 8 - 9
Section A —General Operation
POWERING UP THE CONTROL
When the GEO 360 is powered up, the control displays the control type number in the LCD for 2 seconds. Next, the software
version is displayed for 2 seconds. Finally, the control enters into the normal operating mode.
OPERATION
The GEO 360 uses a floating action mixing valve to vary the supply water temperature to a wet heating system. The supply
water temperature is based on either the current outdoor temperature, or a fixed setpoint.
Outdoor Reset
When the outdoor design (OUTDR DSGN) setting is not set to OFF, the GEO 360
calculates a mixing supply water temperature based on the outdoor air temperature.
The GEO 360 uses a
Characterised Heating Curve
and optionally indoor temperature
feedback from an indoor sensor in this calculation.
Setpoint Control
When the outdoor design (OUTDR DSGN) setting is set to OFF, the GEO 360
supplies a fixed mixing supply temperature equal to the MIX TARGET setting. An
outdoor sensor is not required during this mode of operation.
FLOATING ACTION
A floating action actuator motor is connected to the GEO 360 on the
Pwr Mix
,
Opn
, and
Cls
terminals (9, 10 and 11). The
GEO 360 pulses the actuator motor open or close to maintain the correct mixed supply water temperature at the mix sensor
when there is a mixing demand. The actuator is connected to a 4-way mixing valve. A visual indication as to whether the control
is currently opening or closing the mixing valve is displayed in the LCD.
BOILER PROTECTION (BOIL MIN)
The GEO 360 is capable of providing boiler protection from cold
mixing system return water temperatures. If the boiler sensor
temperature is cooler than the BOIL MIN setting while the boiler
is firing, the GEO 360 reduces the output to the mixing valve. This
limits the amount of cool return water to the boiler and allows the
boiler temperature to recover. This feature can only be used if a
boiler sensor is installed.
EXERCISING
The GEO 360 has a built-in exercising function. If the system pump or valve has not been operated at least once every 3 days,
the control turns on the output for a minimum of 10 seconds. This minimizes the possibility of a pump or valve seizing during a
long period of inactivity. The GEO 360 ensures that the mixing valve operates over its entire range at least once each exercising
period. While the control is exercising the
Test
LED flashes.
Note:
The exercising function does not work if power to the control, pump, or valve is disconnected.
SETBACK (UNOCCUPIED)
To provide greater energy savings, the GEO 360 has a setback capability. With
setback, the supply water temperature in the system is reduced when the building is
unoccupied. By reducing the supply water temperature, air temperature in the space
may be reduced even when the thermostat(s) are not turned down. Any time the
UnO
Sw
(12) and the
Com
(13) terminals are shorted together, the control operates in the
unoccupied (Night) mode. When in the unoccupied (Night) mode, the UNOCC segment
is displayed in the LCD. The GEO 360 adjusts the supply water temperature based on
the UNOCC settings made in the control. This feature has no effect when the control
is used as a setpoint control.
Decreasing Outdoor Temperature
Incr
easing W
a
ter T
e
mperatur
e
Terminal Unit
(Heat Emitter)
Terminal Unit
(Heat Emitter)
Indoor Design
Indoor Design
Outdoor Design
Outdoor Design
Design Supply
Design Supply
Boiler Supply
Sensor
Mix Supply
Sensor
Boiler Return
Sensor
12
UnO
Sw
13
Com
Timer Switch
