O P E R AT I N G A N D I N STA L L AT I O N I N ST R U CT I O N S SYST E M V E N T E C H LG 5 0 0 P
PAG E 1 3
Primary parameters
Description
P-band
• P-band for the pre-heater PI controller.
I-time
• I-time for the pre-heater PI controller.
Set-point, preheater
• Desired air-temperature set-point after pre-heating exchanger.
Pump operation
• “Constant”. The circulating pump in the PWW heater will run
continuously when power to the OJ-Air2Master is on.
• “Auto”. The circulating pump in the PWW heater will run when
heating is required (valve setting >0.1%).
• “Outside temperature”. The circulating pump in the PWW
heater will run when heat is required or when the outside
temperature drops below the value set in the “Pump start”
parameter.
Pump start
• The pump will start when the outside temperature falls below
the set value.
• “Pump operation” must be set to “Outside temperature”.
Motor-driven valve
• Set the control range of the motor-driven valve
(0-10 V/2-10 V).
4.2.3 Frost protection via electric pre-
heating exchanger (optional)
The compact ventilation unit LG 500 P
System VENTECH may optionally be
fitted with an electric pre-heating ex-
changer to protect the heat exchanger
from freezing. The cold outside air will
to this end be pre-heated via a shell and
tube heat exchanger mounted directly in
the outside air duct to counter freezing
of the heat exchanger.
To reduce the consumption of primary
energy, the frost protection strategies
mentioned in Point 4.2.2 are recommen-
ded instead of the electrical versions.
Description of the control system:
The pre-heating exchanger will maintain
a minimum required temperature before
a heat exchanger.
A PI control algorithm is implemented
here. The 0-10 V controller output signal
regulates the pre-heating exchanger’s
power consumption via a Triac control-
ler.
Illustration: Primary parameters
Electrical pre-
heating exchanger
