User Manual

User’s Information Manual
14
4 SMART SYSTEM control module
E: DHW settings
DHW boiler set point
When a DHW call for heat becomes active, the control will use
the DHW boiler set point to determine the firing rate of the
boiler based on the actual water temperature. This parameter
can be changed by the installer by accessing parameter E1. The
temperature range of this parameter is 50°F (10°C) to 190°F
(88°C). The default value is 180°F (82°C).
SH/DHW switching time
The SH/DHW switching time parameter sets the length of time
the control will stay in DHW Mode when a SH call has been
received. After this time period has expired the control will
revert to SH Mode. If a DHW call is still active the timer will
reset. After the time period has expired the control will revert
back to DHW Mode. This will continue until one of the
demands has been satisfied. This parameter can be changed by
the installer by accessing parameter E2. The time range of this
parameter is 10 minutes to 240 minutes. The default value is 30
minutes.
DHW tank set point
By installing a tank sensor, the SMART SYSTEM control can
perform the tank thermostat function. The SMART SYSTEM
control automatically detects the presence of this sensor, and
generates a DHW call for heat when the tank temperature
drops 6°F (3.5°C) below the tank set point, and finishes the call
for heat when the tank temperature goes 4°F (2°C) above the
tank set point. This parameter can be changed by the installer
by accessing parameter E3. The temperature range of this
parameter is 32°F (0°C) to 212°F (100°C). The default value is
125°F (52°C).
F: Outdoor air reset
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 0°F (-18°C) to 120°F (49°C). The default value
is 70°F (21°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 boiler 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°) to 90°F (50°C). The default value is 10°F
(5°C).
Boost temperature
If a SH demand lasts longer than the programmed time delay
setting (F9) and there have been no DHW demands, the control
will increase the water temperature set point by the amount in
this parameter. If the SH demand continues through another
time period, the set point will be increased again. This will
continue until either the SH demand ends, a maximum of 20
increases has occurred, or the maximum set point has been
reached. Once the SH demand has been satisfied the set point
will revert back to its calculated setting. The boost temperature
can be changed by the installer by accessing parameter F8. The
temperature range of this parameter is 0°F (0°C) to 45°F (25°C).
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).
Boost time
The boost time parameter sets the amount of time that must
elapse with a SH demand before the water temperature set point
will be increased. This parameter can be changed by the
installer by accessing parameter F9. The time range for this
parameter is 1 minute to 60 minutes. The default value is 20
minutes.