Viessmann VITOGAS 100 GS1 series Installation Instructions Manual page 14

Connections
Venting Connection
Chimney
A corrosion-resistant approved liner
must be installed in masonry or unlined
chimneys. The liner should be insulated
to prevent condensation of flue gas in
cold weather.
Before connection boiler to existing
chimney, inspect chimney for inside and
outside conditions. Repair or replace
immediately if any leaks or other
defects are found in the vent system.
To avoid chimney condensation, proper
consideration must be given to shortest
possible vent connection, type of vent,
and chimney size.
In replacement installations where the
previous boiler experienced chimney or
vent condensation problems, the
Vitogas 100, GS1 must be installed as
close as possible to the vertical
chimney (relocate water piping if
necessary), and the liner must be
insulated. These measures will help
reduce the likelihood of chimney or vent
flue gas condensation.
Refer to natural draft venting tables in
CSA B149.1 and .2 (Canada) and ANSI
Z223.1 (USA) for every installation for
proper vent diameter. Depending on the
lateral and vertical vent lengths, the
vent diameter may have to be increased
to a size larger than the vent connector
on the draft hood.
Some retrofit installations may require
an engineered vent system specific to
the project site.
If chimney is of multi-fuel design,
ensure local codes permit its use with
the Vitogas 100, GS1 boiler. Ensure
correct flue is chosen for the flue
connection of the boiler.
14
(continued)
Blocked vent and flame roll-out safety
switch
The blocked vent switch is located at
the back of the boiler in the draft hood.
In the event of a complete vent
blockage, the spill switch heats up and
interrupts 24 V to the gas control
shutting down the burner. The switch
requires a manual reset by pushing in
the red button. If the switch activates,
the vent system must be checked
inside and out and the blockage or
defect corrected by a qualified heating
contractor before boiler is put back in
operation.
The flame roll-out switch is located in
the burner area. In the event of
blockage of the cast-iron flue ways
inside the boiler, hot gases will cause
the switch to open, shutting down the
burner. The heat exchanger must be
thoroughly examined and cleaned by a
qualified heating contractor before the
boiler is put back into operation. The
switch requires a manual reset by
pushing the red button when the switch
has sufficiently cooled.
IMPORTANT
In either of the above functions, do not
operate the boiler without the blocked
vent or flame roll-out safety switch(es).
Advise the system operator/ultimate
owner to contact a qualified heating
contractor for service immediately.
IMPORTANT
When installing piping or venting, or
while insulating overhead pipes, do not
stand on top panel of boiler. Advise
other trades accordingly!
Vitogas
Never operate the boiler without an
installed venting system which safely
vents all products of combustion to the
outdoors. The vent system must
comply with all applicable local and/or
national codes.
Vitogas boilers are Category I boilers as
defined in ANSI Z21.13. Boiler category
does not apply when boiler is vented
through the wall with optional power
venter.
The boiler draft hood must not be
altered or modified in the field.
In Canada
For gas boilers install venting system in
accordance with all applicable local
codes. In the absence of local codes,
follow national codes CAN/CSA B149.1
or .2.
In U.S.A.
For boilers for connection to gas vents
or chimneys, vent installations shall be
in accordance with Part 7, Venting of
Equipment, of the National Fuel Gas
Code, ANSI Z223.1 or applicable
provisions of the local building codes.