Pressure Guard - SystemAir SAVE VTR 300/B Installation Manual

7.5.3

Pressure Guard

A differential pressure switch is used to detect air pressure difference in a duct. The contact in the switch changes (on/
off) when air pressure exceeds the setpoint value.
One of the possibilities is to use this device with a cooker hood which has an internal fan. Turned on cooker hood causes
air pressure to increase in the exhaust air duct. After exceeding a set air pressure value in the pressure switch, wires
from the ventilation unit get connected by contact and signal is sent to the ventilation unit to activate the Pressure
Guard function.
1. A differential pressure switch
2. Metal tube
3. Exhaust air direction
4. Exhaust air duct
1. Mount a differential pressure switch in a suitable place,
for example on or near the outlet duct from the kitchen
fan.
Set the pressure switch to the lowest possible pressure,
for example 20 Pa.
2. There are two possible installation cases. A pressure
switch tube is installed in the duct:
a. after the fan – connect plastic tube to P1 positive
pressure connection on the relay, P2 negative pres-
sure connection shall be left open.
b. before the fan – connect plastic tube to P2 negative
pressure connection on the relay, P1 positive pres-
sure connection shall be left open.
Install a rubber bush in the duct. Insert the S-shaped copper pipe into the rubber bushing so that it points towards the
air flow (i.e. towards the outlet opening for the fan).
3. Use strips to lock the rubber tube and the pipe in the correct position.
4. Connect a 2–wire cable from the connection box (UI, 24V) to the pressure
switch terminals (NO and COM).
5. Connect pressure switch wires to one of the 5 universal inputs, marked
"UI1–5" and "24V" on the connection board. "UI1" and "24V" are pre-con-
figured for this function, see wiring diagram of the ventilation unit.
Please contact your installer to find air pressure for your system. It may nec-
essary to perform several tests and calibrations to find pressure, increased by
the cooker hood, at which the differential pressure switch gets activated.
Note:
The exhaust air pressure and air pressure increase caused by the cooker hood is different for each
ventilation system.
Set the switch activation pressure value using the knob under the lid. The setpoint value is visible through
the lid.
Configuration
1. Go to Service menu
2. Enter password (default 1111)
3. Go to Input menu. Select UNIVERSAL tab.
4. Select the universal input to which wire from the differential pressure switch is connected.
Example if it is connected to UI1 on the connection board, then select option UNIVERSAL INPUT 1. Set signal type as
Digital Input and select an option Pressure Guard from the input type list.
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Accessories |
COM
CB
UI
NC
24 V
NO