27
8.7.
Attaching Air Restrictors – Appliances with Vertical Vent Rise Only
No restrictors are required for appliances, which only have a horizontal vent, run.
There are three types of restrictor supplied with each #530 engine unit. They are slightly
different in size. They can be identified by the number of indents – Type 1 has 1 indent, type
2 has 2 indents etc. – See figure 46.
The restrictors cover part of the openings in the firebox rear wall ports – See figure 47.
Each restrictor can be fitted at either Maximum or minimum port opening – See figure 47.
Types 1, 2 and 3 are supplied with ceramic log appliances.
Types 4, 5, and 6 are supplied with ceramic coal appliances.
The correct restrictors to be fitted for each type of installation are shown in the table below.
To fit the restrictors, remove the center screws from the rear ports and fit the restrictors
using these screws. To set the restrictors at maximum port opening, slacken the bottom
screws in the ports, slide the restrictors down as far as possible and tighten the screws over
the restrictors.
To set the restrictors at minimum port opening, slide the restrictors up as far as possible and
tighten the screws. With the largest restrictors, the upper screws may need to be slackened to
allow the restrictors to go under the screw heads.
Vent
terminal
Vertical
vent pipe
run
Use restrictor
type
Port
opening
set at
For
Logs
For
Coal
Horizontal
through
wall
Less than
2ft (61cm)
1 4
Maximum
From
2ft
(61cm) but
less than
4ft
(122cm)
1 4
Minimum
From
4ft
(122cm)
but less
than 6ft
(183cm)
2 5
Maximum
6ft
(183cm)or
more
2 5
Minimum
Vertical
through
roof
Less than
13ft
(396cm)
3 6
Maximum
13ft
(396cm) or
more
3 6
Minimum
Figure 47
Figure 46
