Outdoor Reset Operation - Weil-McLain Evergreen 220 User Manual

™ GAS
Evergreen Control operation

Outdoor reset operation

1. Set desired temperatures for space heating zones.
2. For an explanation of the target temperatures and associated
outdoor temperatures, see Figure 65.
3. The temperature settings discussed below are accessed in the
priority menu for the applicable system. For detailed explanations
of the priority menus, see Figure 73, page 75.
1. Set Supply max to the required supply water temperature for the
system at design maximum heat loss (typically 180°F for finned
tube baseboard on new installations).
1. Supply min should equal the desired minimum supply water
temperature for the system.
2. This could be set as low as 70°F, which would supply "zero heat"
when outdoor temperature is 70°F, because supply water tem-
perature would equal room temperature.
3. See examples in Figure 65.
1. OD RESET MAX means the outdoor temperature at which the
target temperature reaches its minimum (Supply min).
2. In the examples of Figure 65, this occurs at 70 °F (the factory
default).
1. OD RESET MIN means the outdoor temperature at which the
target temperature reaches its maximum value (Supply max).
2. In the examples of Figure 65, this occurs at 0°F outside (the fac-
tory default setting).
3. OD RESET MIN should equal the ODT (outdoor design tem-
perature) for the installation's location.
Remote target operation (0–10VDC input)
1. This function allows a remote analog input to regulate the sup-
ply temperature for control operation/modulation. This can be
done for any priority, including network and local priorities for
multiple boiler networks.
2. The settings discussed below are accessed in the priority menu
for the applicable system. For detailed explanations of the priority
menus, see Figure 73, page 75.
3. See Figure 66 for an explanation of target temperature vs voltage
when using remote target operation.
4. In the priority menu for the applicable system, select 0-10v for
the TARGET ADJUST setting.
5. In the same priority menu, select the VOLTS FOR MIN and VOLTS
FOR MAX values. VOLTS FOR MIN sets the voltage value for the
desired minimum supply temperature. VOLTS FOR MAX sets
the voltage value for the desired maximum supply temperature.
Part number 550-100-131/0715
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FIRED WATER BOILER
— Boiler Manual
(continued)
Outdoor reset operation
Remote target operation
Remote modulation operation
(0–10v input)
1. To use 0-10VDC for remote modulation, go to Con-
tractor Menu -> Assign Inputs. Then change Input 1's
source to 0-10V. The priority that is assigned to Input
1 cannot be used by any other Input.
2. The boiler comes on at 0.9VDC and turns off at 0.8VDC.
1 VDC = 10% input. 10 VDC = 100% input. These volt-
age settings are not adjustable.
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