16
Set points and control strategies
This section describes the different factory settings for HCH 5 and HCH 8 and the pos-
sibilities for adjustments on the control panel and the remote control.
Default factory settings:
Fan Step 4 (maximum speed)
3 to Gear 100
‘OFSET’
(gears between Fan Step1-2-3)
Bypass, Tmax (extract temperature, T3)
Bypass, Tmin (outside temperature, T1)
T3 ≥ 24 °C
-
*Of/22-30 °C
Automatic Demand Mode (RH%)
Frost protection, exchanger
(see below)
Frost protection, after-heat
*)
Selecting ‘of’ eliminates automatic bypass.
The unit’s frost protection works as follows:
1) Frost protection of the exchanger.
The control strategy has a built-in frost protection preventing ice building up in the
heat exchanger.
If the exhaust air temperature (T4) is below + 2 °C for 1½ hours or longer, the unit
starts reducing the flow rate of supply air (i.e. RPM of the supply fan is reduced) until
the exhaust air temperature reaches + 2 °C. Frost protection normally starts when
outdoor temperature (T1) reaches ÷ 6 - ÷ 7 °C, or below.
2) Unit shots down at an outside temperature below ÷ 13 °C
If the outside temperature (T1) is below ÷ 13 °C for more than 5 minutes, the unit will
stop operating for 30 minutes to prevent ice from building up. If the outside temper-
ature does not reach a temperature above ÷ 13 °C, the units shots down for another
Continued overleaf