MODES OF OPERATION
a) Stand-by Mode: when there is no heat demand for central heating or domestic hot water.
b) Domestic Hot Water (DHW) Mode: when there is need for DHW (hot water tap is opened), the
hall effect sensor on the water flow sensor detects the water flow and signals the main board for
DHW delivery.
c) Central Heating (CH) Mode: can be activated in two ways:
- Rotate the CH potentiometer (P1 potentiometer) to the winter mode.
- Internal frost protection requests heat.
d) Frost Protection: It automatically functions according to the water temperature values detected
by CH and DHW temperature sensors in order to protect the water circuits against freezing. The
ON/OFF switch should be in ON position for frost protection system to activate.
e) Service Settings Mode: This mode can be activated by pushing the PB3 service button on the
control panel and is used for boiler settings.
f) Fault/Error Conditions: like sensor faults or over temperature.
The priority of the modes of functions is as follows:
1. Fault/Error Condition
2. Service Settings Mode
3. DHW Mode
4. CH Mode
5. Frost Protection
6. Stand-By Mode
If there is no error or fault, service settings have the highest priority. For example in case of an over
heating condition, the system should reach normal temperature conditions before service settings
mode can be activated.
Stand-by Mode
1
In stand-by mode, the pump does not function (if the pump over-run time is finished), the burner
and the gas valve are OFF.
Domestic Hot Water
2
If there is no error condition and the water flow detected by the hall effect sensor is enough, the
boiler will supply domestic hot water. DHW mode starts when the flow rate reaches 3 lt/min. and
ends when flow rate is less then 2.5 lt/min. The flow sensor has a flow limiter in it. Flow rate is
limited to 10 lt/min. in 24 kW models and 12 lt/min. in 28 kW models.
¨ DHW Mode Control Variables:
- DHW potentiometer (P2 potentiometer)
- Water temperature detected by DHW temperature sensor
- Water flow rate
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