This release is an update to boiler controller product. For full operational details this note should be read in conjunction with Data sheet LIT/DAT/BLR/001 Iss2.0.
Frost protection enhanced
Summer heating disable monitoring
Registration code updated in-line with other system components
BRON - now functions correctly
This version of code runs on the 0004/0002 issue E BLR DIN hardware.
The code is contained in a 27C512 prom with address line switching.
The frost protection set point 'FRST', can now be set to a minimum of 2°C, and the default factory setting is now 3°C.
Frost protection can now be disabled, by setting 'FRST' to 0 (please be aware of the consequences of doing this). Once Frost protection is disabled the boiler controller will no longer protect the system at low outside temperatures Stage1 frost protection, Stages 2 and 3 are now combined and will ultimately protect the system, if any of the water temperatures fall to 5°C (fixed) at which point the boiler will fire until the lowest water temperature reaches 30°C, at which point the boiler and pumps will be disabled and the cycle will repeat.
How to disable frost protection.
Access the 'FRST' config variable, and reduce it to its lowest allowable setting of 2°C,
now put the boiler controller into manual and short the outside sensor connection. Refresh
the 'FRST' variable it will now display as 0°C, this value can now be written (ie.
pressing the override button on the zone controller) to the controller. Take the
controller out of manual and remove the shorting link, confirm the 'FRST' setting is 0°C,
the variable is now fixed at 0°C and cannot be adjusted by normal methods.
To re-enable frost protection, select the 'FRST' variable and put the boiler controller
into manual, when a write is made to the controller the 'FRST' variable will default back
to 2°C. Take the boiler controller out of manual operation, the 'FRST' variable can now
be set as normal to any permissible value.
There are three plots setup on the first three 'sensors'.
Plot 1 Measured Flow temperature
Plot 2 Measured Return temperature
Plot 3 Measured Variable Circuit temperature
This controller now has Configurable
Plots like most of the other SeaChange controllers. These plots are now
automatically re-scaled within the controller to achieve the best resolution
for the data recorded. This happens at the end of every 96 readings when new
maximum and minimum settings are calculated and also if a new value is outside
the current range settings.
The two extra inputs are treated as digital inputs and their current state is viewable in Doorway as I1 and I2. A '1' condition indicates that the terminals are shorted. Two new config variables are supported 'Alarm state' - 'ALST' and 'Alarm mode' - 'ALRM' . A 'danger of freezing alarm' has also been added, this will create an alarm if the lowest temperature reading of Flow, Return and VT is lower than 5 degC. Frost protect should prevent this happening. Five degrees is used to allow for measurement errors and poor conductivity between the sensor and the water. The sense of the alarm state is defined by config variable 'ALST' 'alarm_state' 0 or 1, this equates to short circuit or open circuit on the input terminals. ALRM Alarm mode - This takes a number of values which function as described in the Config Tables .
The state of the alarms can be monitored in Doorway by reading config variables 90-99.
To use these alarm features new Boiler hardware is required with issue 3a or later software. The SLT also needs to have new software probably this will be the full release of issue 1g. Cascade and pump changeover modules will also need updated software.
New monitoring variable added 'Summer heating off' - 'SHOF', this is
read only and enables the user to determine is the summer hold off is active.
0 = Heating Enabled
1 = Heating disabled
The Heat source 'HTSC' of any device registed to the boiler controller is set to 1, previously this variable was not set. This enables all products to be shipped from the factory with a default HTSC of 0.
The BLR controller can be specified for operation in a Open System, bound by 3rd party tools. (Specify Secondary Boiler in Open System format)
'BRON' Boiler pump run on feature, now functions correctly. In the
previous release the pummp run on period would expire while the boilers where running,
causing the pump to stop almost immediately when the boilers stopped.
Changes to Configuration variables this issue refer to Config Tables