Johnson Controls UL Listed GS-20 Series Manual page 10

GS-_ _2_
(On/Off Step-
slow Opening
with Flow
Adjustment)
GS-_03_
(On/Off with
Pressure
Regulator)
GS-405_
(On/Off with
Servo Precision
Regulator)
10 G—UL Listed GS-20/25 and GS-40/45 Series Single-block Multi-function Gas Control Valves Technical Bulletin
This valve provides adjustable step/slow opening for smooth ignition in a
burner application. The valve is factory set to maximum start gas position
and maximum flow position. Adjust the hydraulic damper at the top of the
solenoid coil to set the desired flow rate through the valve as well as the
desired start gas flow rate.
To adjust the maximum flow rate, loosen the unsealed mounting screw on
the aluminum hydraulic damper housing. Hand turn the housing clockwise
until the desired setting is obtained. Tighten the mounting screw to secure
the adjustment knob at the desired flow rate.
To adjust the start gas position, remove the plastic cap from the hydraulic
damper housing and turn the brass screw clockwise until the desired
setting is obtained (see Figure 6). Replace the plastic cap.
Figure 6: Hydraulic Damper Housing
This valve provides spring regulation to maintain the gas pressure at the
valve outlet. For outlet pressure adjustment, loosen the unsealed mounting
screw on the plastic regulator knob at the top of the solenoid coil. Hand
turn the regulator knob clockwise to increase or counterclockwise to
decrease the outlet pressure of the valve (see Figure 7). Tighten the
mounting screw to secure the adjustment knob at the desired outlet
pressure.
Figure 7: Spring Pressure Regulator Adjustment Knob
This valve provides servo regulation for precision control of the valve
outlet pressure. Before setting the valve for the desired outlet pressure,
adjust the start gas pressure.
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