VOKERA Maxin 24e, Инструкция по установке и обслуживанию

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32
MAXIN 24e & 28e
Conversely a fall in temperature of the
primary water will increase the low voltage
to the modulator coil and this in turn in-
creases the gas rate accordingly.
Constant monitoring of the temperature of
the primary water by the thermistor will
regulate the gas rate between high & low
rate to maintain an average heat input.
NOTE: As the thermistor senses the tem-
perature of the primary water leaving the
main heat exchanger, the amount of heat
transferred from the primary water to the
dhw water depends upon the temperature
differential between them.
When the dhw water draw off rate drops
below the permitted minimum (2.8 l/min) the
single micro switch is deactivated, and the
appliance either reverts to the 'Rest' mode
where the fan may overrun to remove
residual heat, or if there is a call for heating
to the mode described below.
9.2.2 Central Heating Mode
In this mode the mode selector switch must
be turned to the position.
With all controls calling for heat the pump
will run and provided sufficient primary
water is circulating the flow switch is acti-
vated.
The fan will run and the pressure differen-
tial switch will be activated. This in turn will
energise the electronic ignition control box.
The gas valve will be energised and the
electrode will start to spark.
If a flame is detected during the ignition
attempt period, (8-12 seconds) the sparking
will cease and the gas valve will remain
energised. The gas rate will increase to the
gas rate for c/h which was predetermined at
the commissioning stage by an on-site
adjustment of the potentiometer to suit the
system requirements.
The temperature rise of the primary water is
sensed by the thermistor on the three port
diverter valve.
As the temperature of the primary water
approaches that set on the c/h temperature
control, the voltage to the modulator coil
will decrease and thus lower the gas rate.
On reaching the set temperature the gas
valve is de-energised and the burner is
extinguished.
The appliance has an inbuilt delay timer
and re-ignition will not be attempted for
approximately 3 minutes.
Conversely a fall in temperature of the
primary water will increase the voltage to
the modulator coil and therfore increase the
gas rate.
SECTION 9 OPERATIONAL CHECKS AND WIRING DIAGRAMS
9.1 On completion of any service/fault finding
task which has required the breaking and
remaking of electrical connections, the
checks Earth Continuity, polarity and Resist-
ance to Earth must be repeated.
The following flow diagrams suggest the
logical sequence of steps for fault finding.
They are not exhaustive but cover all that
can reasonably be carried out on site by the
installer.
Acquaintance with the functional sequence
will prove helpful for some, and this is
included for reference. As further help, the
role of each part is briefly described.
Also included in this section are wiring
diagrams and schematics to assist in fault
location and servicing as described in the
text.
9.2 Sequence of Functions
When following this sequence, refer to figs.
37 & 38. It is assumed that the mode
selector switch is in the position.
9.2.1 Domestic Hot Water Mode
Turning on a tap will cause the domestic
diaphragm to move operating the hot water
flow microswitch.
The domestic diaphragm acts on the
diverter valve which diverts the primary
water to the domestic heat exchanger.
Activation of the microswitch will start the
fan and pump, the fan will change over the
pressure differential switch. With sufficient
primary water circulating around the appli-
ance the flow switch is operated. Once
these actions have been proven the gas
valve will be energised and the electrode
will start to spark.
If a flame is detected during the ignition
attempt time (8-12 seconds) the sparking will
cease and the gas valve will remain ener-
gised and the appliance will produce hot
water as described below.
If a flame is not detected the appliance will
go to lockout (failure to detect a flame during
ignition attempt time). At which time the gas
valve will be de-energised and the sparking
will stop.
To reset the appliance after lockout depress
the ignition reset button on the front control
panel which will be illuminated.
The temperature rise of primary water in
the appliance is sensed by a thermistor on
the three port diverter valve. An increase in
temperature will in turn decrease the
voltage reaching the modulator coil causing
the gas rate to be lowered, if the tempera-
ture rise is too great the gas valve can turn
off completely.