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Doku VARIOMAX_engl_06 12
June. 2012
Goch GmbH & Co. KG
c) Checking Nozzle Pressure
Connect pressure measuring device to nozzle test nipple (see Combination Valve
–
Top View)
Turn on heater
Compare measured nozzle pressure to rating plate specifications. If necessary,
use pressure regulator to correct.
6. Two-stage Heater Startup
For the two-stage
VARIOMAX
, the power control is not performed through
conventional pressure level changing. It is performed by means of a
double nozzle
with High-low valve
which allows two-stage regulation under constant gas pressure.
The input load is controlled by changing nozzle orifice size. The input load is
controlled by changing nozzle orifice size. At full load, the two nozzle orifices are
open. At half load, an electrically operated rod closes one of the orifices. In this
position the heater receives only 50% of the nominal input load.
a) Open the manual gas valve and measure the gas supply line pressure at the test
socket (see Combination Valve
– Top View). The connected gas supply pressure
must comply with the specifications in Ch. 3 “Energy Supply”, otherwise the startup
must be interrupted.
Perform leak test at the ball valve and the screw connection up to the gas hose.
In case of appropriate gas supply pressure, the heater may be turned on using the
respective switching system (either switchbox or switching- and control system).
Measure the gas supply pressure again during full load operation. If the
gas pressure is too low, the operation must be interrupted. After
measurement, close gas pressure test socket.
b) Operating Sequence of the SG 300 Controller and Two-Stage Operation
Connect electricity to unit.
The voltage applied to the solenoid valve turns the heater on at full load.
The heater switches on correctly only at full load.
Two-stage Heater
