©
2010 D
270
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08/10
4
of
24
Section A
General
Operation
Page 4 - 5
Section B
Boiler
Operation
Page 5 - 7
Section C
Pump
Operation
Page 8
The following defined terms and symbols are used throughout this manual to bring attention to the presence of hazards of various risk
levels, or to important information concerning the life of the product.
- Warning Symbol: Indicates presence of hazards which can cause severe personal injury, death or
substantial property damage if ignored.
- Double insulated
- Local level, appliances
INSTALLATION
CATEGORY II
Definitions
Section D
Boiler Reset
Operation
Page 8 - 10
Section E
DHW
Operation
Page 10 - 13
POWERING UP THE CONTROL
When the control is powered up, all segments in the LCD are turned on for 2 seconds. Next, 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 control stages or modulates the boiler to control supply water temperature to a hydronic system. The supply water temperature
is based on outdoor reset or a fixed temperature for DHW.
Outdoor Reset
When a boiler demand signal from the heating system is present, the control operates the boiler(s) to maintain the supply
temperature based on the outdoor air temperature and the Characterized Heating Curve settings. Refer to section D.
DHW
When a DHW demand is present, the control operates the boiler to maintain the supply water temperature at least as hot as the
DHW exchange setting or high enough to satisfy tank temperature. Refer to section E.
13
Com
14
UnO
Sw
UnOccupied
Switch
SETBACK (Occ and UnOcc)
To provide greater energy savings, the control has a setback feature. With setback, the
supply water temperature in the system is reduced when the building is unoccupied. By
reducing the supply water temperature, the air temperature in the space may be reduced
even when thermostat(s) are not turned down. Any time the
UnO Sw
(18) and the
Com
(17)
are shorted together, the control operates in the unoccupied mode.
When in the unoccupied mode, the
UNOCC
segment is displayed in the LCD. The control
adjusts the supply water temperature based on the
UNOCC
settings made in the control.
Section A: General Operation
Sequence of Operation