Installation & Operation Manual
7 Operating information
Temperature control
Firing rate
Depending upon the model, the
Ramp delay (boiler only)
For systems with lower flow, the SMART SYSTEM can limit the firing rate (when enabled) when a space heating call for heat starts, or when switching from a DHW call for heat to a space heating call for heat. There are six (6) limits that can be programmed, as well as six (6) time intervals corresponding to each limit. The sixth limit will also limit the firing rate for the rest of the call for heat.
Gradient limiting
If during operation of the heater the outlet water temperature is rising too quickly, the control will reduce the firing rate to its lowest setting.
Outdoor air reset (boiler only)
With the outdoor air sensor 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 (boiler only)
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 DHW demands, the control may be programmed to increase the set point by a fixed number of degrees (adjustable by installer). This process will repeat 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 (boilers) and tank set points during a certain time each day. A start and stop time can be programmed for each day of the week.
Protection features
Outlet temperature, and temperature rise limiting
The outlet temperature is monitored by the boiler outlet temperature sensor. When the outlet temperature exceeds 230°F (110°C) (boilers) or 190°F (88°C) (water heaters), the unit will reduce the firing rate. If the outlet water temperature exceeds 235°F (113°C) (boilers) or 200° (93°C) (water heaters) the control will shut the unit down until it cools off.
The control monitors the temperature difference between the inlet and the outlet sensor. If this difference exceeds the first limit the control will turn off stages. If the temperature difference exceeds a second limit the control will shut the unit down. The unit will restart automatically once the temperature difference has dropped 10°F (6°C) and the minimum off time has expired.
Freeze protection
DO NOT install the appliance in a room likely to freeze.
The following integral feature of the SMART SYSTEM control module provides some protection for the appliance only
•The SMART SYSTEM control module provides
•Below 45°F (7.2°C), the appliance and system pumps operate constantly.
•Below 37°F (2.7°C), the appliance turns on.
•Appliance and pumps turn off if appliance water temperature rises above 45°F (7.2°C).
CAUTION This feature of the SMART SYSTEM control module does not eliminate the
possibility of freezing. The installer must still use recognized design, installation and maintenance practice to prevent freeze potential for the appliance and system.
High limit operations
When outlet temperature exceeds 240°F (116°C) (boilers) or 210°F (99°C) (water heaters), high limit action occurs. The appliance shuts down until the outlet water cools down and the RESET button on the Operator Interface is pressed.
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