Hamworthy Purewell Variheat mk2 110c, Инструкция по установке, наладке и обслуживанию

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HAMWORTHY HEATING LTD
24
PUREWELL Variheat mk2 218612 A03
8.2.2 Operating Phases
Comprehensive details on the boilers operating phases can be found in the separate
Navistem instruction
manual, HHL part no. 500001310, which is supplied with each boiler.
8.3 - Functions
8.3.1 Frost Protection
Note: - to access this function, the circulating pump must be wired to the Navistem boiler control through a
suitable contactor.
There are two levels of frost protection available dependent on the sensor options used.
1st stage - When the boiler water temperature is below 5°C, the burner and the heating pump are switched on.
When the temperature increases and exceeds 15°C, the burner stops and the pump continues for the duration of
the pump overrun.
2nd stage - This additional function uses the outside air temperature (if a sensor has not been fitted, the function
is blocked) and provides three levels of activation.

If the outside temperature is less than or equal to –5°C, the pump operates continuously

If the outside temperature is between –4 & 1.5°C, the pump operates for 10 minutes every 6 hours.

If the outside temperature is greater than 1.5°C, the pump is switched off.
Note:- any demand for dhw is given priority.
Should protection be required for the building fabric, then a QAA74 programmable room sensor must be used to
maintain the internal building temperature.
8.3.2 Pump overrun
When the heating mode ends, the heating circuit pump remains on for a period (depending on the settings used -
QAA74: 544).
In dhw systems, when the dhw heating period ends, the heating pump remains on until the return temperature
drops below 70°C. During this period, the dhw selector valve (if fitted) is in the open position.
8.3.3 Boiler overheat protection
The boiler flow sensor in combination with the return sensor, provide overheat protection as follows:

If the first level temperature is exceeded, a fault code is displayed.

If the second level temperature is exceeded, an alarm code is displayed and the boiler will switch off. The
boiler must be reset to restart.
To restart the boiler, the temperature must fall, accordingly the fan and pump will continue to operate until the
boiler heat exchanger temperature drops.
Additionally, should the ∆ T across the boiler heat exchanger exceed 25°C, the burner will reduce output to
minimum rate. Should the ∆ T exceed 30°C, the burner will shutdown.
8.3.4 Volts Free Contacts
Comprehensive details on the boilers Volts Free contacts can be found in the separate
Navistem instruction
manual, HHL part no. 500001310, which is supplied with each boiler.
8.3.5 0-10V Control
This boiler has the ability for 0-10V Control, for more information please refer to page 60.
8.3.6 Cascade Operation
This boiler has the ability for Cascade Operation, for more information please refer to page 59.