Ariston MICROCOMBI 23 MFFI, Installation And Servicing Instructions

Page: 14 / 65

F
IG
2.17
IMPORTANT!!!
W
HERE CONDENSE WILL FORM WITHIN
THE FLUE SYSTEM
,
ENSURE THERE IS A
FALL BACK TO THE BOILER OF
3
O
AND A
SUITABLE TRAP IS FITTED AS CLOSE TO
THE BOILER AS POSSIBLE
. MTS
SUPPLY
A S U I TA B L E C O L L E C TO R
P
A RT
N
O
.
705798
OR A CONDENSATE DISCHARGE
T
W I T H B U I LT I N T R A P
P
A RT
N
O
.
705774.
14
F
IG
2.16
F
IG
2.18
To utilise the air intake it is necessary to:
Remove the ‘knockout’ of the air intake by cutting it with a
suitable knife
(F
IG
. 2.16).
Insert the elbow/flue pipe into the air intake until it stops.
The twin flue pipes can be fitted with or without additional
elbows and need no clamps, simply ensure that the red o-
ring is inserted in the female end of the flue pipe and push
the extension piece fully into the previous section of flue
pipe or elbow, check that the o-ring is not dislodged when
assembling the flue.
Twin pipe can also be converted back to Coaxial flue to
enable vertical termination with a coaxial kit by using the
pipe bridge (Twin - Coaxial Adaptor - Part No. 705767).
When running the twin flue pipe vertically, a condense trap
must always be used on the exhaust pipe.
It is not recommended that the pipe bridge for horizontal
termination, however in the unlikely event that this proves
to be a necessity it is extremely important that the entire
flue has a fall of 3
o
back to the boiler, is suitably trapped
and where the 60mm inner flue of the concentric terminal
connects to the pipe bridge, this point must be adequately
sealed with silicone sealant to avoid condense leakage at
this point.
N
OTE
:
Vertical twin flue installations must have a trap on
the exhaust. MTS supply a suitable condense
trap Part No. 705774 and recommend that this be
used in the event that the flue may not form
condense.
When siting the twin flue pipe, the air intake and exhaust
terminals must terminate on the same wall, the centres of
the terminals
must be a minimum of 280 mm apart and
the air intake must not be sited above the exhaust
terminal (refer to F
IG
. 2.20). The air intake pipe can be
run horizontally, however, the terminal and the final 1
metre of flue must be installed with a fall away from the
boiler to avoid rain ingress.
It is also strongly recommended that the air intake pipe run
be constructed of insulated pipe to prevent condense
forming on the outside of the tube.
The maximum permissible flue length for twin flue is
dependent on the type of run used.
For flue runs with the intake and exhaust pipes under the
same atmospheric conditions (T
YPE
4) the maximum
length is 43 metres (23kW) and 28 metres (27kW), for
runs with the terminals under different atmospheric
conditions (T
YPE
5) the exhaust terminal must extend 0.5
metres above the ridge of the roof (this is not obligatory if
the exhaust and air intake pipes are located on the sa,e
side of the building). For T
YPE
5 also, the maximum
permissible combined length is 40 metres.
The maximum length is reached by combining the total
lengths of both the air intake and exhaust pipes. Therefore
a maximum length of 40 metres for example, will allow a
flue run of 20 metres for the air intake and 20 metres for
the exhaust pipes, also for each 90
o
elbow 1.3 metres must
be subtracted from the total length and for each 45 o elbow
1 metre must be subtracted from the total flue length.
Some of the acceptable flue configurations are detailed on
below
(F
IG
. 2.19).
For further information relating to flue runs not illustrated,
please contact the Technical Depar tment on 01494
539579.