Installation & Operation Manual
7 Operating information (continued)
Low water cutoff protection
1.The SMART SYSTEM control module uses temperature sensing of both inlet and outlet areas of the heat exchanger. If the flow rate is too low or the outlet temperature too high, the control module modulates and shuts the appliance down. This along with the flow switch, ensures appliance shutdown in the event of low water or low flow conditions.
2.Some codes and jurisdiction may accept these integral features of the control in lieu of requiring an additional limit control or low water cutoff. Consult local jurisdiction to determine. Contact manufacturer for low water cutoff kit availability.
Monitor external limits
Connections are provided on the connection board for external limits such as a louver proving switch. The SMART SYSTEM will shut off the burner and inhibit relighting whenever any of these external limits open.
Run-time and alarm outputs
The appliance provides dry contacts for indicating when the appliance is running, and when it is unable to operate.
Run-time and cycle counting
The control uses two timers to monitor the total hours of burner operation. One timer monitors the time the appliance is firing under 50% of rate. The other timer monitors the time the appliance is firing over 50% rate.
The control uses four (4) ignition counters to monitor the amount of appliance cycles. The first counter counts all ignitions of the control. The second counter counts only ignition attempts that have failed. The third and fourth counters are the same as the first and second respectively, but can be reset by the installer.
Service reminder
The control can be programmed for service reminder notification. This notification will become active when either a set time frame has expired, or a set amount of running hours or cycles has expired (all adjustable by the installer). The display will alternate the standard text on the display screen with Service Due every 5 seconds. The service reminder notification can be reset by the installer.
Error logging
The control will hold in memory the last 10 error codes as well as the last 10
Boiler temperature regulation
Operating temperature (target)
The SMART SYSTEM control module senses water temperature and regulates appliance firing and firing rate to achieve a target temperature. The target temperature can be set between 70°F (21°C) and 220°F (104°C) (boilers) or between 60°F (16°C) and 190°F (88°C) (water heaters).
•Target temperature is fixed when the outdoor sensor is not installed (boilers).
•Target temperature is calculated as described under “Outdoor Air Reset Operation” and “Boost Function” when the outdoor sensor is connected (boilers).
Outdoor reset operation, if used (boilers only)
Target temperature with outdoor reset
This feature improves the system’s efficiency as the outdoor temperature warms up.
See the
Reset curve
The reset curve looks at outdoor air temperature and adjusts the set point.
Cascade
When multiple appliances are installed, they can be wired together in a cascade sequence. A maximum of eight appliances can be controlled from a single control. In this application one appliance would be designated as the Leader control and all others would be designated as Member controls. The set point or firing rate can be controlled by the 0 - 10V input as well.
Once the Leader appliance receives a call for heat from a BMS, tank sensor, or external thermostat, the control will determine what the set point will be. A fixed temperature set point can be programmed into the control. See
On boilers, if the water temperature at the system sensor is less than the set point + the
On water heaters, if the water temperature at the tank sensor is less than the tank set point - the off differential, then the control will initiate a call for heat on the Cascade.
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