Instructions condensing Air heaters type HR
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7
Functioning of the unit
7.1 General
The unit can heat as well as ventilate. By using the temperature-sensor on the unit and the one
in the room-thermostat, the temperature-difference between the two in the room is monitored.
Should the difference become higher than a set value, due to the fact that warm air has
accumulated underneath the roof, the system-fan will start and push the warm air down, acting
as a de-stratification fan.
7.2 Heat demand
If the thermostat indicates heat demand, the following cycle will commence:
1.
Pre purge
: The electronic circuit board acknowledges the heat-demand and the premix
burner fan will start running for 30 seconds. Display print
1
2.
Ignition
: After 30 seconds of pre purge the electrode will spark for max. 5 seconds, the
gas valve is opened and the gas-air mixture will ignite. Display print
2
3.
Burn
: When the flame is detected Display print
b. the unit will modulate to the desired
load after ca. 15 seconds. Depending on the given load, the system fan will start
modulating (step-less) as well. The air heater will
always burn for a minimum of 4
minutes
. This is to evaporate eventual condensation in the discharge system.
4.
End of heat demand:
When the heat demand ends, the burner will switch off and the
system fan will continue to run for ca. 3 minutes in order to cool the unit down (Display
print
P).
The unit will try to ignite twice before lockout on flame fault.
In the case of flame failure during operation, the heater will attempt one restart.
When the heater is in lockout you see in the display intermittent an A1. On the display of the
room thermostat you see failure 1.
7.3 Delta-T-regulation (temperature controlled de-stratification fan)
In case there is no heat demand, the delta-T-regulation will be active.
When the temperature-difference between the sensor on the unit (the NTC) and the sensor in
the thermostat is bigger than the set value (factory setting standard 8°C), the system fan will
start, at a regulated speed, depending on the differential temperature difference. This operation
ensures an even temperature distribution throughout the building, thus acting as a fully
automatic variable de-stratification fan. Should this delta-T-regulation not be required, in the
Menu Program Settings on the room thermostat this regulation can be switched off. See user
manual of the special Winterwarm Room thermostat.
7.4 Summer ventilation
It is possible to let the ventilator run on a certain speed in the summer. Please follow the
instructions in the manual from the thermostat.
7.5 High limit protection
7.5.1 T max. Heat exchanger
The unit contains 2 temperature protections. The NTC thermostat monitors the air temperature
electronically. Should the temperature, in a first step, become too high, the burner will modulate
to the minimum input and the system fan will modulate to the maximum speed.
When the temperature still increases, the burner will switch off (on display you see intermittent
an E1). When the heat exchanger has been cooled to normal levels the burner will start
automatically.
Should the temperature increase to an unacceptable level, the heater stops (on the display you
see intermittent A2). Only after a manual reset the heater can start again. Manual reset can be
done on the electronic circuit board or with the special Winterwarm Room thermostat
