!
Preheater
plug
min. length: 0.5m
SPR-C-160
SPR-C-160
HRQ-PremAIR-HDE
MSF-C-160
FSBQL-160 +
FSBQ-W3-160
ALNOR
®
ventilation systems
is a legally protected trademark and technical patent. All rights reserved.
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User Manual
HRU-PremAIR
6.3 Frost protection
Frost protection is achieved by reducing the supply fan’s revolutions to the minimum level of the fan. The
whole process goes gradually, depending on the outdoor temperature drop. When the outdoor temperature
continues to decrease and the fan has reached the set minimum revolutions, the extract fan will start to
gradually increase its revolutions. The advantages of this method are a lower airflow unbalance in the system
and the possibility for the unit to work with the pre-heater during the defrosting phase.
The algorithm works when:
The outdoor temperature < Defrosting set point for frost protection (#40) + Offset for frost protection
defrost (#114) Where #40 should be as low as possible as it is responsible for the frost temperature.
The advantage of this method is lower imbalance of the flow system and the possibility of cooperation with
the pre-heater during defrosting operation
NOTE:
After a power on, the frost protection mode is blocked for 5 minutes.
Figure 26 - preheater connection
6.4 Preheater HRQ-PremAIR-HDE-160-1,5 (optional)
Preheater is optional equipment and it can be mounted to
provide additional frost protection.
To install preheater you need HRQ-PremAIR-HDE-160-1,5
(electric heater with special plug).
Figure 26 shows sample connection of preheater.
We suggest to use filter before HRQ-PremAIR-HDE-160-1,5 to
prevent heater coils from dirt and extend product life-span.
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 <
0˚C
(Pre-heater setpoint #46).
• Toutdoor <
-3˚C
(Frost protection Pre-heater setpoint #39).
• 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 >
0°C
(Pre-heater setpoint #46) +3
°
C
(Pre-heater off temp difference #47)
• The supply fan is off
