Table of Contents
Advertisement
SECTION 1 - DESIGN PRINCIPLES AND OPERATING SEQUENCE
1.1 PRINCIPLE COMPONENTS
- A fully integrated electronic control board featuring electronic tem-
perature control, anti-cycle control, pump over-run, self-diagnostic
fault indicator and premix burner control
- Low-water-content, aluminium heat exchanger
- Electronic ignition with flame supervision
- Integral high-head pump
- Fan
- Expansion vessel
- Water pressure sensor/gauge
- Two-stage gas valve
- Condensate level sensor
- Safety valve
1.2 MODE OF OPERATION (see section 7 for detailed information)
When the appliance is connected to the electrical supply, there are
5-possible modes of operation:
- STANDBY- Heating and DHW functions are disabled, however
anti-freeze and anti-seize functions are active*
- HEATING ON- Heating and DHW functions enabled with TOUCH
& GO function and SARA function active
- HEATING OFF - DHW only enabled, TOUCH & GO function active
* Anti-freeze & anti-seize functions are active in all operating modes.
1.3 MODE OF OPERATION (Heating)
When there is a request for heat via the programmer/time clock and/
or any external control, the pump and fan are started, the fan speed
will modulate until the correct signal voltage is received at the control
PCB. At this point an ignition sequence is enabled.
Ignition is sensed by the electronic circuitry to ensure flame stabil-
ity at the burner. Once successful ignition has been achieved, the
electronic circuitry increases the gas rate to 75% for a period of
15 minutes (adjustable, see parameter 28, cap. 7.3.1). Thereafter,
the boiler's output will either increase to maximum or modulate to
suit the set requirement. When the appliance reaches the desired
temperature the burner will shut down and the boiler will perform a
five-minute anti-cycle (timer delay). When the request for heat has
been satisfied the appliance pump and fan may continue to operate
to dissipate any residual heat within the appliance.
1.4 MODE OF OPERATION (DHW)
When there is a request for DHW via a hot water outlet or tap, the
pump and fan are started, the fan speed will modulate until the cor-
rect signal voltage is received at the control PCB. At this point an
ignition sequence is enabled.
Ignition is sensed by the electronic circuitry to ensure flame stability
at the burner. Once successful ignition has been achieved, the elec-
tronic circuitry increases the gas rate to maximum or will modulate
output to stabilise the temperature.
In the event of the appliance exceeding the desired temperature
(set point) the burner will shut down until the temperature drops*.
When the request for DHW has been satisfied the appliance pump
and fan may continue to operate to dissipate any residual heat
within the appliance.
*When the appliance is in the SUMMER mode, the burner will remain
on minimum power even if the set point has been achieved.
1.5 SAFETY DEVICES
When the appliance is in use, safe operation is ensured by:
- a water pressure sensor that monitors system water pressure
and will de-activate the pump, fan, and burner should the system
water pressure drop below the rated tolerance;
- 2 temperature sensors that control and prevent the over-heating
of the circuit, interrupting the operation of the burner;
- a differential temperature protection circuit which interrupts the
burner if the temperature differential is too high or inverted;
- a fan speed sensor that checks the correct operation of the fan,
thereby allowing safe operation of the burner;
- a sensor that interrupts the operation of the appliance if the con-
dense pipe becomes blocked;
- a safety valve which releases excess pressure from the primary
circuit.
1.6 OPTIONAL ACCESSORIES
The Linea ONE is suitable for use with a range of optional accessories
that enable enhanced operation and/or applications. These include:
- external sensor that enables the appliance to automatically adjust
its outlet flow temperature in response to the outside temperature
- RF wireless room thermostat.
return
temperature
sensor
expansion
vessel
transducer
pump
diverter
valve
safety
valve
automatic
by-pass
CH
return
Fig. 3
top AAV
flow
temperature
sensor
main heat
exchanger
water pres-
sure sensor
& gauge
DHW
heat exchanger
DHW
temperature
sensor
flow regu-
lator
DHW
DHW
non-return
flow
valve
meter
CH
DHW
Domestic cold
flow
outlet
water inlet
3
Advertisement
Table of Contents
