ALNOR
®
ventilation systems
is a legally protected trademark and technical patent. All rights reserved.
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User Manual
HRU-MinistAIR
6
.5 Built-in heater (optional)
Heater is optional equipment and it can be mounted to provide additional frost protection.
After hardware connection preheater works when these conditions are true:
1. The pre-heater is switched on in case all following conditions are true:
• (T
outdoor
+ T
exhaust)
/ 2 < (Pre-heater setpoint #46 [
0˚C
]).
• T
outdoor
<
(Frost protection Pre-heater setpoint #39 [
-3˚C
]).
• The supply fan is on (needed for cooling of the heater).
2. The pre-heater is switched off in case at least one of the following conditions is true:
• (T
outdoor
+ T
exhaust
) / 2 >
(Pre-heater setpoint #46 [
0°C
]) + (Pre-heater off temp difference #47[
-3°C
])
• The supply fan is off.
• Temperature sensor at the X23 intake is damaged.
• The unit during start-up (5 min).
6
.6 By-pass
6.6.1 Passive Heating
Passive Heating can be used to heat a building with outdoor air when the room temperature is lower than the
outside temperature and lower than the temp setpoint.
For example, in the spring, after a cool night, a cooled down building may be heated by outdoor air, which
has been heated by the sun throughout the day.
Passive heating may also be referred to as ‚Free heating’, as no conventional energy consumption needed.
Heating is possible when all of the following conditions are met:
• The outdoor temperature ≥ the extract temperature (room temperature) + 5˚C (Free ventilation outside
offset #118).
Heating is not possible when one of the following conditions is met:
• The outdoor temperature ≤ the extract temperature (room temperature) + 5˚C
(Free ventilation outside offset #118 -0,5˚C).
Heating is activated when all of the following conditions are met:
• Heating is possible.
• The extract temperature (room temperature) ≤ +20˚C (Free ventilation heating setpoint #117).
Heating is deactivated when one of the following conditions is met:
• Heating is not possible.
• The extract temperature (room temperature) ≥ +20˚C (Free ventilation heating setpoint #117 + 0.5˚C).
When heating is activated the bypass is fully (100%) opened.
Then, based on the temperature reading, it closes smoothly if the temperature exceeds the set level.
