Lochinvar SYNC 1.3 - Manual (Page 50)

10
Operating information
50
Installation & Operation Manual
Gradient limiting
If during operation of the boiler the outlet water temperature
is rising too quickly, the control will reduce the firing rate
to its lowest setting.
Outdoor air reset
If an outdoor air sensor is connected, the control module
will calculate the set point based on the programmed reset
curve. The installer can change the slope of the reset curve
by several adjustable parameters. The user can limit the
maximum set point for the system using the space heating
set point.
Boost function
If outdoor air reset is active, and a space heating demand
has been active continuously for a set period of time
(time adjustable by installer) and there has been no HW
demands, the control will increase the set point by a fixed
number of degrees (adjustable by installer). This process
will continue until the space heating demand ends, the set
point reaches the programmed set point or a maximum of
20 increases has occurred. Once the system heat demand
is satisfied, the set point will revert to the value determined
by the reset curve.
Night setback
The controller may be programmed to reduce the space
heating set point during a certain time each day. A start
and stop time can be programmed for each day of the week.
Flame current support
To prevent nuisance shutdowns when the boiler is firing
at minimum rates, the control will increase the firing rate
when the flame signal drops too low.
Protection features
Outlet temperature, flue temperature, and temperature
rise limiting
The outlet temperature is monitored by the boiler outlet
temperature sensor. When the outlet temperature exceeds
185°F, the unit will reduce the fan speed. If the outlet water
temperature exceeds 195°F (90°C) the control will shut the unit
down until it cools off.
The control module monitors the flue temperature by a sensor
located in the flue exhaust. If the flue temperature exceeds
215°F (102°C) the control will reduce the maximum fan speed.
If the flue temperature exceeds 240°F (115°C) the control will
shut the unit down. The unit will restart automatically once
the flue temperature drops 25°F (14°C) and the minimum off
time has expired.
The control monitors the temperature difference between
the inlet and the outlet sensor. If this difference exceeds
55°F (13°C) the control will reduce the fan speed. If the
temperature difference exceeds 60°F (15°C) the control will
shut the unit down. The unit will restart automatically once
the temperature difference has dropped below 55°F (31°C) and
the minimum off time has expired.
Freeze protection
DO NOT install the boiler in a room likely to freeze.
The following integral feature of the SMART TOUCH control
module provides some protection for the boiler only -- not for
the system.
• The SMART TOUCH control module provides
freeze-up protection as follows when the boiler
water temperature drops below 45°F (7°C):
• Below 45°F (7°C), the boiler and system pumps
operate constantly.
• Below 37°F (3°C), the boiler turns on.
• Boiler and pumps turn off if boiler water
temperature rises above 45°F (7°C).
This feature of the SMART TOUCH control
module does not eliminate the possibility
of freezing. The installation must still
use recognized design, installation and
maintenance practice to prevent freeze
potential for the boiler and system.
ƽ CAUTION