Bryan Boilers 200, 250, & 300 Master Active Service, Master Service Status, Modulation Sensor

following sources of demand. All sources that are currently calling for heat will be true (multiple items may be true at the same time) except when WWSD is active, then CH demand is inhibited.

CH Demand

CH Frost demand – true if any slave is calling for CH frost protection and Frost protection enable is true.

4.7.4MASTER ACTIVE SERVICE

Is a data item which contains the identity of a single source of demand that the LL Master is currently serving according to its priority:

•None – no active service, LL master is idle

•CH

•Frost – burner demand is true for frost protection

•WWSD – no high priority demand is active, and WWSD is inhibiting CH demand (if any).

MASTER SERVICE STATUS

Is a data item used by pump control logic that combines the Master Heat Demand and Master Active Service data. It is implemented as described by the Pump Control Block diagram.

Outdoor Temperature

For a Sola that hosts a LL master, the outdoor temperature may be known from either of two sources. If the host Sola has an outdoor sensor that is reporting a valid temperature then this sensor reading is used. Otherwise, if any slave Sola is reporting a valid temperature as part of its Data Poll message, then this temperature is used.

The resulting outdoor temperature provides all outdoor temperature needs for both stand-alone and LL master purposes. If neither source has a valid temperature then the outdoor temperature is simply invalid and unknown, and the functions which need this information handle it accordingly per their individual definitions.

Modulation

Each demand source has one or more setpoints that may be active and an operation sensor.

65

Date: 8-4-2010

Revision: 0

Form: 2396

These are used to detect turn-on and turn-off conditions. The difference between operating point and setpoint determines the LL master's firing rate

4.7.5MODULATION SENSOR

LL MODULATION SENSOR: S5

The LL master's modulation sensor uses the S5 sensor (connector J8 terminal 11 and 12). If the

LLmaster is enabled and its sensor is faulty then an alert will be issued.

LL MODULATION BACKUP SENSOR: DISABLE, LEAD OUTLET, SLAVE OUTLET AVERAGE

If the sensor chosen by the LL Modulation sensor is faulty then the backup sensor provided here may be used.

If Disable is selected then no backup will be used.

If Lead Outlet is selected then the outlet temperature of the lead boiler will be used as the backup during firing.

If Slave Outlet Average is selected then average of the outlet temperatures of all slave boilers that are firing will be used as a backup. When the burner demand is off and no burners are firing then, for either Lead Outlet or Slave Outlet Average, the lead boiler's outlet temperature is used to monitor for burner demand.

Setpoints

LLCH SETPOINT SOURCE: LOCAL, S2 4- 20MA

If the setpoint source is Local then the Sola control's local setpoint system is used. This setting enables the normal use of the CH setpoint, CH TOD setpoint, and the CH outdoor reset parameters and functions.

If the setpoint source is S2 4-20mAthen the setpoint is determined by the 4-20mA input on S2, and the two parameters described below. If the 4-20mA signal goes out of range or is invalid, and this persists for a specified time, then the setpoint source reverts to "Local". In this case once it has gone to "Local", it remains