VOKERA Eclipse 216 ESS Installation & Servicing Instructions Manual - page 4
Supplied By www.heating spares.co Tel. 0161 620 6677
2
SECTION 1
DESIGN PRINCIPLES AND OPERATING SEQUENCE
1.1
PRINCIPLE COMPONENTS
●
A fully integrated electronic control board
featuring electronic temperature control,
continuous air/gas modulation, anti-cycle
control, pump over-run, self-diagnostic fault
indicator, electronic ignition with flame
supervision, & appliance frost protection.
●
Cast aluminium mono-block heat exchanger.
●
Low Nox burner with pre-mix.
●
Two-stage gas valve.
●
Pump.
●
Expansion vessel.
●
Pressure gauge.
●
Safety valve.
1.2
MODE OF OPERATION (at rest)
When there is no demand for heating or hot
water. And the appliance remains inactive for a
period of 24 hours, the pump will be energised for
a few moments to prevent it from seizing. Should
the flow temperature sensor fall below 7
°
C the
pump will be energised.
If the flow sensor temperature falls to below 3
°
C
the burner will be lit and the appliance will operate
at the minimum output until the temperature of
the flow sensor reaches 10
°
C, whereupon the
pump will continue to run in pump over-run mode.
1.3
MODE OF OPERATION (heating/hot water
request)
When there is a request for heat via the time clock
and/or external controls, the pump will start and
the fan will be activated via the flow temperature
sensor. When the fan is sensed to be operating
correctly, the ignition sequence commences. The
speed of the fan and therefore the output of the
boiler is determined by the temperature of the
water sensed by the flow & return temperature
sensors, consequently a high temperature at the
flow sensor results in a lower fan speed. As the
water temperature increases, the temperature
sensors – located on the flow & return pipes of the
boiler – reduce the fan speed via the electronic
circuitry. Depending on the load, either the water
temperature will continue to rise until the set point
is achieved or the water temperature will fall
whereby fan speed will increase relative to the
output required. When the boiler has reached the
set point, the burner will switch off. The built-in
anti-cycle device prevents the burner from re-
lighting for an adjustable period of time (factory
default is 3 minutes). When the temperature of
the flow sensor falls below the set-point, the
burner will re-light.
1.4
SAFETY DEVICES
When the appliance is in use, safe operation is
ensured by:
●
a high limit thermostat that interrupts the
operation of the burner;
●
a differential temperature protection circuit which
interrupts the burner if the temperature
differential is inverted;
●
a fan speed sensor which checks the correct
operation of the fan, thereby allowing safe
operation of the burner;
●
a safety valve which releases excess pressure
from the primary circuit.
●
a condense pressure switch that will stop the
burner from operating should the condense
trap become blocked.
Fig. 2
return flow
gas
1
Main Heat
Exchanger
Expansion
vessel
4