DU/SD SERIES INSTALL OPERATION MAINTENANCE MANUAL
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3.4.8 Setting the Modulating Valve Motor
The ball valve to motor alignment and limits are factory preset. Site gas pressure may differ to factory settings therefore
requiring modulating motor limit adjustment.
Aligning the Motor and Valve Shaft
1.
Open gas valve fully with motor removed. (This is indicated by the valve shaft flat facing outwards) Removal of the
adaptor shaft may be required to identify the shaft flat.
2. Reinstall adaptor shaft ensuring grub screws are tight.
3. Set modulating motor to 90
o
and install over the adaptor shaft. Tighten no.9 SHCS in Figure 17: Modulating Motor
onto Adaptor Shaft.
Setting Modulating Motor
The minimum low fire rate must not be less than 59% of full fire rate.
To set the fire rate follow the steps below;
1. Engage the slider (6) to disengage the gear train, set the modulating ball valve to 100% open
2. Check the test point pressure against the full gas setting
3.
Low fire may be adjusted by limiting the travel of the modulating valve, utilizing adjusting screw (9) to ensure the
gas cuts off before the rate is reduced too far. A rate equal to 59% of full gas rate may be obtained by adjusting the
gas flow at the low fire setting, which equates to the correct minimum gas flow rate.
NG: Full Gas = .870kPa, Low Gas = .300kPa, LPG: Full Gas = 2.5kPa, Low Gas = .875kPa
Correct adjustment MUST be made, too low gas pressure will result in a “light-back” condition, damaging the
burner’s ports and result in a buildup of soot and replacement of burners.
AMI011-B
Figure 17: Modulating Motor
INSTALLATION INFORMATION
1. BASE PLATE AND MOUNTING
2. ROTATIONAL ANGLE SCALES
0º...90º / 90º...0º
3. DIL SWITCHES FOR
- SELF ADAPTION
- ROTATIONAL MOVEMENT DIRECTION
- INVERTED OR NON INVERTED OUTPUT
VOLTAGE OPERATING FUNCTION
4. COVER FOR DIL SWITCHES
5. CONNECTING CABLE FOR POWER, CONTROL SIGNAL,
AND POSITION INDICATION
6. SLIDER TO DISENGAGE THE GEAR TRAIN
7. COUPLING BUSHING
8. CENTERING ELEMENT FOR GLB...1E
(SHAFT DIAMETER 8....10MM)
9. POSITION INDICATOR
10. ADJUSTMENT LEVER WITH SHAFT FASTENING SCREW
11. ADJUSTING SCREW FOR ROTATIONAL ANGLE
LIMITATION
12. MOUNTING BRACKET
