LLCH DEMAND SWITCH: DISABLE, STAT, ENVIRONCOM REMOTE STAT
The inputs that can function as the CH demand switch are: STAT, EnvironCOM Remote Stat. If the CH demand switch value is Disable, the LL master does not respond to CH demand.
Warm Weather Shutdown
WARM WEATHER SHUTDOWN ENABLE: DISABLE, SHUTDOWN AFTER DEMANDS
HAVE ENDED, SHUTDOWN IMMEDIATELY WARM WEATHER SHUTDOWN SETPOINT:
TEMPERATURE OR NONE
When warm weather shutdown is Disabled then it has no effect (i.e. the Warm Weather Shutdown (WWSD) status shown on the priority diagram is false).
These two parameters are shared by the stand- alone Sola control and the LL master and have the same effect for either control.
This function requires the outdoor temperature. This temperature may be obtained from either a local sensor or a LL slave. If WWSD is enabled but the outdoor temperature is invalid and unknown, then the WWSD function acts as if it is disabled and has no effect and an alert is issued indicating an invalid outdoor temperature.
If it is enabled then it uses a 4°F (2.2°C) hysteresis:
If WWSD is false, then when the Outdoor temperature is above the value provided by Warm weather shutdown setpoint then:
If "Shutdown after demands have ended" is selected then any current CH demand that is present prevents WWSD from becoming true; that is if CH demand is false then WWSD becomes true.
Otherwise if "Shutdown immediately" is selected then WWSD becomes true, it immediatetly causes CH demand to end.
If WWSD is true, then when the Outdoor temperature is below the value provided by Warm weather shutdown setpoint minus 4°F (2.2°C) then WWSD becomes false.
When warm weather shutdown is true then:
64
Date: 8-4-2010
Revision: 0
Form: 2396
New occurrences of CH demand is inhibited. DHW demand is not affected.
Frost protection
LLmaster frost protection is enabled with Frost protection enable: Disable, Enable
The need for frost protection is actually detected independently by each slave which notifies the master whether frost detection occurred in CH frost detection, and/or its DHW frost detection, and whether it is severe enough to require burner firing as well as pump operation. This is done via its Slave status parameter.
If Frost protection enable is Enable then the master's Slave write message, will indicate CH or DHW frost protection or both as read from each slave's Slave Status. This will cause any slave pumps which are enabled to follow this status to turn on without any other action required from the master.
If any slave is indicating CH or DHW frost protection, and additionally that slave's Slave status register indicates burner firing is requested then the LL master's frost protection burner demand will be true.
If the priority scheme allows the master to honor this demand, then it will fire a single burner (the current lead burner as specified by the sequencer) at the rate indicated by Frost protection rate:
Priority Control
CH heat demand is a simple signal such as STAT, Enviro- COM remote stat, or Warm Weather Shutdown.
Frost protection input to the priority logic is not a heat demand, it is a burner demand (because frost protection always turns on pumps without regard to the priority control - it is a priority item only if it also wants to fire).
Master Status
MASTER HEAT DEMAND
Is a data item which contains the status for the