Lochinvar Power-fin 502 Service Manual page 17

1
Service
(continued)
Figure 1-1_Outdoor Air Reset Curve
Maximum SH set point
When the outdoor temperature drops to its minimum
setting (F1) the water temperature will be at this point, if
the SH set point is set higher (FIG. 1-1). This parameter
can be changed by the installer by accessing parameter F3.
The temperature range of this parameter is 32°F (0°C) to
248°F (120°C). The default value is 180°F (82°C).
Minimum SH set point
When the outdoor temperature rises to or above its
maximum setting (F2) the water temperature will be at this
point (FIG. 1-1). This parameter can be changed by the
installer by accessing parameter F4. The temperature range
of this parameter is 32°F (0°C) to 248°F (120°C). The
default value is 70°F (21°C).
Outdoor air shutdown
When the outdoor temperature rises above this point, the
control will block all SH demands (DHW demands will still
be active). This parameter can be changed by the user or
the installer by accessing parameter F5. The temperature
range of this parameter is 32°F (0°C) to 122°F (50°C). The
default value is 80°F (27°C).
Outdoor air shutdown differential
The outdoor air shutdown differential parameter is the number
of degrees below parameter F5 the outdoor air temperature must
go before the unit will respond to a SH demand. This parameter
can be changed by the user or the installer by accessing
parameter F6. The temperature range of this parameter is 0°F
(0°C) to 90°F (50°C). The default value is 10°F (5°C).
Shift reset curve
The shift reset curve parameter shifts the actual set point above
the calculated set point the number of degrees in this parameter.
This parameter can be changed by the installer by accessing
parameter F7. The temperature range of this parameter is -27°F
(-15°C) to 27°F (15°). The default value is 0°F (0°C). This
feature will be active if this parameter is set to anything other
than 0°F (0°C).
Service Manual
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