103
General functions
SMGB0066 rev.0 - 12/2009
Controller pack
Service Manual
4
function
•
With some boilers, especially oil boilers, there is a risk of unwanted liquid condensation on the gas side of the boiler
heat exchanger if the temperature falls below the water condensation temperature. This can cause reduced boiler life. In
these situations, it is desirable to allow the boiler heat exchanger to warm up before the heating circuit water is circulated
through the heat exchanger. This function prevents the mixing valve opening until after the boiler has been switched on
for a set period of time (parameter P35).
The recommended setting will depend on the size and type of boiler. (delay time can be set between 1 and 20 minutes).
Parameter Setting
•
P35 Mixing Valve Opening Delay Time (default OFF)
note
If P35 is set to OFF, this function is disabled.
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4.9. GEnErAl fUnCTIonS
4.9.1. System frost Protection
function
•
The System Controller has a frost protection function to help prevent the heating system pipe-work freezing. When the
actual outside temperature falls below the parameter (P22) , the supply water temperature will be maintained at least at
the parameter value (P21). A switching differential of 1K is applied.
Outside temperature (TEXT) < P22
Supply Setpoint (SSUP) determined by heating or DHW demand but always >= P21
Outside temperature (TEXT) > P22+1K Supply Setpoint (SSUP) determined by heating or DHW demand.
Parameter Settings
•
P21 Frost Protection minimum Supply Temperature (default 20°C)
P22 Frost Protection Activation Temperature (default 2°C)
Enable/ disable
•
To disable the system frost protection function, set P22=OFF.
4.9.2 Automatic Summer Switch-off
function
•
At higher outside temperatures it doesn’t make sense to keep heating the building. The System Controller will switch
the heating off when the average daily outdoor temperature (averaged over 24hrs) rises above the parameter (P26). A
control differential of +/-0.5K is applied.
Algorithm
•
Average Outside Temperature > P26
Summer Switch-Off condition is active.
Average Outside Temperature < P26-0.5K
Summer Switch-Off condition is not active.
When the Summer Switch-Off condition is active, the heating is switched off.
Parameter Settings
•
P26 Summer Switch-off Temperature (default 20°C)
Enable/disable
•
To disable the automatic summer switch-off function, set P26=OFF.
