In standby mode, it is possible to view both the heating supply set point temperature and the “domestic hot water reference set point”. The “domestic hot water reference set point” plus 45°F equals the boiler supply set point when it is responding to a call from the indirect water zone. It is not the actual domestic hot water set point. The FCM is designed for use with a storage type indirect water heater such as the Alliance. The domestic water set point is controlled by the thermostat on the indirect water heater. The “default domestic water reference set point” is 135°F and target boiler supply temperature when responding to a call from the indirect water heater is therefore 180°F (135°F +45°F). The default heating supply set point (parameter 4) is 180°F.
In standby mode it is also possible to turn on or off either the heating or domestic water zone. There is normally no reason to turn off either of these zones and doing so is not recommended.
CAUTION
PUSHING AND HOLDING THE “+” WHILE IN STANDBY MODE WILL PREVENT THE BOILER FROM RESPONDING TO A CALL FOR HEAT. PUSHING AND HOLDING THE
In standby mode, if “Mode” and either “+” or
In Parameter mode both set points can be changed and both zones turned on or off. In addition, both zones can be
configured for continuous pump operation. If the heating zone is set for continuous pump operation (parameter 3 set to 3), the heating pump will still shut down when there is a call for domestic hot water.
If either the heating supply set point (parameter 4) , or the DHW reference set point (parameter 1) are set above their factory set values, the boiler supply temperature will exceed 180°F and there is a possibility that the safety temperature limit will open. If this happens, the boiler will shut down and a “b26” error will appear on the display. The boiler will resume normal operation without manual intervention when the safety limit closes (this behavior is common on conventional boilers).
Information mode is used to view various temperatures and settings but cannot be used to change parameters or otherwise control the boiler. The information available is shown in Figure 12.2 and is largely
In information mode, the “supply water temperature set point” (Step 6), is the supply temperature set point for the zone to which the boiler is currently responding (either heat or DHW). If an outdoor sensor is connected to the boiler, and the boiler is responding to a call for heat, this value will be the current point on the reset curve. When no call for heat or DHW is present, Step 6 shows the heating supply set point.
In some cases a
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