such exposed conditions should be avoided. When operating at low fan speeds flame lift
may occur. This can be overcome by raising the minimum fan speed.
In certain conditions pluming from the flue, although harmless, may cause a nuisance.
Please site the flue outlet to minimise any inconvenience the discharge of combustion
products or possible pluming may cause. Where a terminal is so sited to be less than
2m above the level of any ground, balcony, flat roof, or place to which people have
access, or there is a likelihood of accidental contact by persons or damage to the
terminal, a suitable guard
MUST
be fitted. Terminal guards are available from Mikrofill.
17.4 Condensate in the Flue
Condensate formed must be cleared from the flue system and adequate care is required
to ensure all flue pipes are self draining. All internal and external potential collecting
points must be drained. In addition to avoid freezing external flue ductwork must be
insulated.
To ensure the safe and satisfactory operation of the boiler the chimney system must be
capable of the complete evacuation of combustion products at all times.
17.5 Flue Options
The boiler may be installed either as a room sealed, fanned flued appliance using the
Mikrofill P.P.S plastic 125mm/80mm concentric flue system or alternatively,
conventionally flued, using a single skin 80mm P.P.S. plastic pipe.
17.6 Installing a Concentric Flue
Connect the concentric elbow into the flue/vent connection. Mark the wall around the
flue, remove the concentric elbow cover the appliance and cut or drill a 130mm diameter
hole through the wall. Measure and cut the concentric flue pipe to pass through the
previously made hole and into the concentric 90
o
bend.
Figure 13 Flue Preparation
Apply a chamfered edge to the cut ends, apply silicone lubricant and insert through the
wall and into the flue/air socket. The overall projection of the finished pipe should leave
the air holes 20mm clear of the surrounding wall as per figure 15.
NOTE: When fitted, it is important to position the flue outlet with a slight fall so that the
80mm flue pipe is sloped back towards the boiler.
