Adjusting The Diffuser; Air Adjuster Disc: Combi 21 Only; Recommissioning - Grant Vortex Series Installation And Servicing Instructions

11.5 ADJUSTING THE DIFFUSER

Adjust the diffuser position. Refer to Figure 10-5.
! NOTE !
The distance between the end of the burner head and the
front face of the diffuser (D) MUST be correctly set for the
burner to operate correctly.
• Refer to Table 2-2 for the required distance (head setting) for
the boiler output required.
• Check the distance D using the gauge plate supplied with the
boiler.
• To use the gauge plate:
- Position the gauge plate on the burner head as shown in
Figure 10-5.
- Locate the gauge plate with the correct steps (i.e. the
two marked with the required distance D) resting on the
edge of the burner head.
- Check the gauge plate is at 90° to the end of the burner
head and is positioned at the full diameter of the head.
- If distance D is correct, the tongue of the gauge plate
should just make contact with the diffuser with BOTH
steps still in contact with the edge of the burner head.
- If the steps are not in contact with the edge of the burner
head when the tongue of the gauge plate is touching the
diffuser, the diffuser must be 'opened' (see below).
- If the tongue does not reach the diffuser when the steps
are in contact with the edge of the burner head, the
diffuser must be 'closed' (see below).
• To adjust the diffuser position:
- If necessary, adjust distance D using the black
adjustment knob located around the oil supply pipe on
the front of the burner. Refer to item A (Figure 10-5). Re-
check distance D using the gauge plate, as described
above.
- For easier access to the adjustment knob, pull the
photocell out from the burner housing.
- To increase distance D (to open the diffuser): rotate the
knob clockwise - indicated as '+' on the knob.
- To decrease distance D (to close the diffuser): rotate the
knob anti-clockwise - indicated as '-' on the knob.
! NOTE !
One full rotation of the adjustment knob is approximately 1
mm of diffuser movement.
! NOTE !
It is essential that the final position of the diffuser is
checked, using the gauge plate provided with the boiler
and the diffuser adjusted as necessary to achieve the
required distance D.
Section 11: Servicing
11.6 AIR ADJUSTER DISC:
COMBI 21 ONLY
Refer to Section 10.3.

11.7 RECOMMISSIONING

! WARNING !
To ensure safe and efficient operation of the boiler it is
important that re-commissioning is carried out, especially
combustion checks (%CO
smoke number) after the boiler has been serviced. Refer to
the Commissioning instructions in Section 10.
level, flue gas temperature and
2
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