Functions - Hamworthy F40V Installation, Commissioning And Operating Instructions

8.3 - Functions

8.3.1 Frost Protection
Note: - to access this function, the circulating pump
must be wired to the LMU 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 QAA73 programmable room sensor must be
used to maintain the internal building temperature.
8.3.2 Anti Legionella
To prevent the development of pathogenic bacteria in
the domestic hot water tank during prolonged shut
downs or low storage temperatures, the dhw must be
heated once a week to a temperature greater than 60°
C.
The anti legionella function heats the dhw once a
week on Monday, after the first load, to 65°C.
8.3.3 Pump overrun
When the heating mode ends, the heating circuit
pump remains on for a period (depending on the
settings used - QAA73: 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.
8.3.4 Pump or selector valve kick
If either the heating circuit pump or dhw selector valve
have not been activated for more than 24hours, then
during an off period the pump or valve is activated for
5 seconds.
8.3.5 Boiler overheat protection
The boiler flow sensor in combination with the return
sensor, provide overheat protection as follows:
HAMWORTHY HEATING LTD

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.
8.3.6 Anti-cycling
Dependent on the installation and the minimum firing
rate of the boiler, the control monitors the heating
temperature curve and will hold off a boiler from firing
and thus reduce the number of operations.
8.3.7 Automatic summer / winter switching
Note: - This function is only available when an outside
sensor is fitted.
The automatic summer/ winter switching function
enables the summer mode to be switched to winter
mode (vice versa) throughout the year, without the
need for manual intervention.
The heating is shut down when the average outside
temperature measured over the preceding 24hours is
greater than 1°C above the set point (20°C).
The heating is automatically started up again when the
average outside temperature measured over the
preceding 24hours is less than 1°C below the lower
limit of the hysteresis threshold of the set point
C).
Note: - The switch over setting is set to 19°C and can
only be changed using the QAA73 room sensor.
The automatic mode must obviously be activated on
the boiler as well as on the QAA73, for the function to
operate. The function is automatically activated by a
default setting in the QAA73.
8.3.8 - Start-up / initialisation
On startup after power-On, or after a lockout reset, the
setpoints will be initialized.
These setpoints apply until a first adjustment is made
(e.g. via the display or PC parameterization):
After a readjustment, these values will be overwritten
with the new value and permanently stored in the LMU.
When a new startup is made, or after power-On, the
previous settings will be stored in the LMU.
Also, the software version number of the operator
module and that of the connected type of LMU... will be
delivered to the display.
31
FLEET V series
(18°
500001213/G