Controller pack
Service Manual
102
Mixing valve control functions
SMGB0066 rev.0 - 12/2009
4.8.2. Mixing / Bypass Valve Control
Configuration Specific
•
This function only applies to configuration 5 (CONF 5)
function
•
When the boiler is switched on, the mixing valve control is enabled and operates in the same manner as described
above (Mixing Valve Control).
When the boiler is switched off, and the difference between the supply water temperature (TSUP) and mixed supply
temperature (TMIX) is small (less than EP3), the mixing valve is always closed (by-pass operation) so that the hot
supply water from the heat Pump does not circulate through the boiler heat exchanger, which may cause unnecessary
heat loss and reduction in system efficiency. While the water from the boiler (TSUP) is much hotter than the mixed supply
temperature (TSUP), the mixing control continues to operate.
Parameter Setting
•
P9 Mixing Valve Runtime (default 120 sec)
EP3 Difference Supply water temperature (default 1.5K)
The value for EP3 has been chosen based on laboratory tests and it is not recommended to change it.
note
Engineering Parameters (EP) are only available for service engineers.
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4.8.3. Mixed Heating Circuit Maximum Temperature limit Protection
Configuration Specific
•
This function only applies to configurations 4 and 5 (CONF 4,5)
function
•
The secondary circulation pump is switched off and the mixing valve closed when the maximum supply temperature
(mixing circuit) setting is exceeded. This function helps prevent damage to floor heating systems by very high
temperatures.
TMIX > P6
Pump switched off, mixing valve closed.
TMIX < P6 – 5K
Returns to normal control.
Parameter Setting
•
P6 Maximum Supply Temperature
note
A fault code is displayed when the maximum limit is exceeded.
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4.8.4. Mixing Valve opening delay
Configuration Specific
•
This function only applies to configurations 4 and 5 (CONF 4,5)
