Technical data

12
4.6 FIT THE FLUE - Figs. 12, 13
1. The following procedure applies to both rear or side exit flue. The only difference being the lengths to which the ducts are cut.
Rear flue Outer air duct length = finished wall thickness + 135 mm.
Inner flue duct length = finished wall thickness + 172 mm.
Side flue Outer air duct length = finished wall thickness + the distance from the inside wall to the side of the boiler + 145 mm.
Inner flue duct length = finished wall thickness + the distance from the inside wall to the side of the boiler + 182 mm.
2. If the overall length of the inner duct is greater than 750 mm then a flue extension is required. To fit an extension refer to
the following section.
3. Withdraw the inner flue duct from the outer air duct.
4. Mark the outer air duct to match the length given above, measure from the end of the tube as shown in Figs. 12 and 13.
5. Mark the inner flue duct to match the length given above.
6. Cut both the inner and outer ducts to length.
Note: Do not cut the outer duct end with the two holes, these are for securing the terminal.
Ensure that all cuts are square and burr free.
7. Fit the flue terminal to the outer duct ensuring it is fully located and secure with the two screws provided.
8. Place the inner flue duct back into the outer duct.
9. Pass the flue assembly through the wall (from inside or outside).
Note: Internal fitting - If there is no access to make good the outside wall, locate and secure the flue sealing collar onto
the outer duct of the flue immediately before the terminal. Push the flue assembly through the 127 mm flue hole, so that
the collar completely passes through the wall. Then pull the flue assembly back into the correct position. Visually check
that the collar is sealing the outside wall and that it is not restricting any of the openings of the flue terminal.
10. Position the seal and clamp (two screws), supplied with the bend, over the boiler flue adaptor. Fit the bend and rotate to
the correct position, then secure in position. See Fig 12.
Note: Ensure that the seal is located over both the bend and the flue adaptor.
11. Place the inner (no seal) duct clamp in position over the bend outlet as shown in Figs. 12 and 13, and position the outer
duct seal over the bend.
12. Push the outer duct into the wall slightly at the same time as pulling the inner duct towards the bend, inserting it fully into
the clamp on the bend. Tighten the clamp to secure the inner duct.
Note: Ensure the inner duct clamp screwed joint is at the bottom.
13. Pull the outer duct towards the bend. Check that the flue terminal protrudes 130 mm out of the wall, then position the seal
equally over the joint between the bend and the outer duct. Dismantle the clamp, position it over the seal (if applicable)
and secure in position.
14. Make good the inside and outside walls. The flue sealing collar could be used for making good either the outside or inside
by locating it over the outer duct of the flue and pushing it tight against the wall. If fitting the collar externally, ensure it does
not restrict any of the openings of the flue terminal.
Alpha SY9-24 - Installation
Fig. 12 - Rear flue