A.O. Smith FMD 40 Manuale Utente

11

1.  Cut 5 1/2” (13.97 cm) diameter holes through the roof and ceiling 

directly in line with the fl ue connection on top of the water heater. 
For a sloped roof, the roof hole may have to be enlarged to allow 
the roof jack to be installed vertically.

2.  Telescope down the fl ue pipe in the roof jack assembly to a length 

that will project at least 6 inches (15 cm) below the fi nished ceiling 
before installing the roof jack assembly.

NOTE: Flue pipe joints have silicone seals that must remain in place. 
A soapy water solution sprayed around the seal area will enable the 
fl ue pipe and outer pipe below to telescope more freely.

3.  Telescope down the outer pipe of the roof jack assembly to a length 

that will project at least 2” (5.08 cm) below the fi nished  ceiling 
before installing the roof jack assembly, see Figure 14.

                     

4.  Ease the roof jack assembly through the roof and ceiling openings. 

The roof jack fl ashing tilts up to 22.6° degrees for use on a sloping 
roof.

5.  Use sealant or caulk on the roof to seal under fl ashing of the roof 

jack assembly. Use roof nails or screws on wood construction or 
sheet metal screws on metal roofs (nails and screws not provided), 
see Figure 15.

                 

NOTE: An optional Roof jack Extension Pipe (9002588) is required 
when the roof pitch is 5 1/2” (13.97 cm) or greater, or where local 
codes require the roof jack cap (outlet) terminate above the peak of 
the roof.

6.  Remove the paper backing from the 1 1/2” x 9 3/4” (3.81 cm x 24.77 

cm) woven tape seal (found attached to the heater top) and apply 
the seal around the fl ue collar of the water heater, see Figure 16 
on page 12.