Vallox 252 M Manual Download

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VALLOX 252 M

Heat Recovery Defrosting

The TS5 temperature thermostat directs the operation of the preheater
(LP1) on the basis of the measurement data supplied by the temperature
sensor, preventing the risk of freezing and the stopping of the supply air
fan (TF). If the capacity of the preheater (LP1) is not sufficient, or if there is
no preheater, the TS1 defrosting thermostat of the heat recovery cells
stops the TF supply air fan on the basis of the measuring data on the
temperature sensor, thereby preventing the heat recovery cell from free-
zing. As soon as the risk of frosting passes, the fan restarts automatically.
The threshold temperature for defrosting (-2…+6 ˚C) and the difference
area (2 ˚C) can be set on the thermostat.

Overheating Protection of the Heating Unit

Overheat protection thermostats TZ1 and TZ2 monitor the surface tempe-
rature in the LP1 heating unit. If surface temperature exceeds the
threshold, overheat protection is triggered and power supply to the hea-
ting unit is stopped. The TZ1 overheating protector is reset automatically,
and the TZ2 protector manually.

Damper Motors of the Outdoor and/or Extract Air Ducts

The spring return damper motors (24VAC) that may be installed outside
the ventilation unit, in the outdoor or extract air ducts, can be controlled
with control voltage (24 VAC) coming from the ventilation unit: when the
ventilation unit is stopped, also the control voltage fed from the unit is
stopped.

Alarms

The PDS1 and PDS2 pressure difference switches monitor the pressure
difference on the supply and discharge air sides. If the pressure differen-
ce grows too large because of dirty filters or clogged ducts, remote moni-
toring receives potential free operation mode information from the unit.

Control of Operation

If needed, the ventilation unit can be stopped by controlling the contac-
tors in the unit (Min., 1/2, Max.) or by controlling power supply via the
contactor in the distribution panel.

Fan Speed Adjustment

The ventilation unit can feed control voltage (24VAC) to the remote moni-
toring center, and the remote monitoring center can then direct the fan
capacity of the ventilation unit in three steps according to the control
signal (24VAC) received by the Min., 1/2, and Max. contacts in the
connection box. Remote monitoring receives potential free operation mo-
de information on the mode selected (Min., 1/2, Max.).

Supply Air Temperature

A regulating valve (not included in the VALLOX 252 delivery) directs the
operation of the LP2 post-heating unit on the basis of the measurement
data given by the thermostat sensor in the supply air duct. The aiming is
to keep supply air temperature at the temperature value set with the regu-
lating valve (10…25 ˚C).

Heat Recovery Bypass

With the help of control voltage (24VAC) fed from the ventilation unit to
the remote monitoring center and its control functions, the heat recovery
bypass function can be directed according to the control signal (24 VAC)
received by the NC contact in the connection box. When heat recovery
bypass is activated, the preheater (LP1), if used, and the post-heating unit
(LP2) are deactivated.

DESCRIPTION OF OPERATION VALLOX 252 M VKL REMOTE MONITORING CONTROL UNIT

Parts List

Damper motor

Automatic heat recovery bypass 24V, 2W, 8Nm

Standard

LP1

Preheater

Electric radiator 2.5kW

Options

LP2

Post-heating unit

Water radiator 5kW, 70/50oC