FUTURE® S AIR HANDLING UNIT
OPERATION AND MAINTENANCE
INSTRUCTIONS
15 December 2020
Ver 1.7 (We reserve the right to changes without prior notice)
37
9.6 Preheating coil for the duct (accessory)
WARNING
Electrical connections must be made by a qualified and authorised electrician only. The
condition of the cables connected to the unit must be inspected visually before making any
electrical connections and starting the unit. Before starting any installation and
maintenance work on the electrical device, make absolutely sure that the device is de-
energised. After switching off the power, wait at least five minutes to allow dangerous
voltages to discharge from the devices. Electrical devices should be inspected every six
months. Any deficiencies and faults must be rectified immediately.
CAUTION
The protective devices for the electric components must be dimensioned correctly in order
to guarantee safe use of the unit.
Future® S units equipped with plate heat recovery system can be fitted with an optional electric fresh air
preheating coil installed in the duct. The preheating coil is dimensioned with the Future® S dimensioning
program and its technical specifications are available in the ventilation unit’s technical printout.
The preheating coil has an independent temperature controller and overheating protector and it is supplied
with a temperature sensor installed in the duct. The preheating coil heats the fresh air entering the
ventilation unit to the temperature set on the heater controller (e.g. -
15 ˚C) according to its own temperature
measurement. The controller’s temperature range is -20 -
> +10 ˚C.
The preheating coil must be equipped with its own supply cable and a correctly dimensioned safety switch.
The preheating coil is installed, connected and serviced according to the heater manufacturer’s instructions.
The heater’s safety distance requirements must be taken into account in design.
When using an electric preheating coil, it must be ensured that the heater does not receive a start signal if
the air speed in the heater is less than 1.5 m/s. In addition, in connection of switching off the ventilation unit,
the preheater’s start signal must be removed at least 3 minutes before switching off the fans to ensure
adequate after-ventilation. The preheater includes an access point for start signal control and overheating
protector indication.
The FxVent controller has a built-in preheater start signal control and after-ventilation and an outdoor
temperature limit above which the preheating enable is out of use. In order to ensure optimal operation, the
outside temperature limit must be set two degrees higher than the target temperature set in the preheater
controller. If the Future® S unit does not have an FxVent controller, start signal control, after-ventilation and
outdoor temperature limit must be implemented with a building automation system.
Summary of Contents for Future S
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