General Rigid Pipe Installation Information; Installation Steps (Outline); Vent System Manufacturers; Leak Test (For Coaxial Venting Systems Only) - Viessmann Vitocrossal 300 CU3A Installation Instructions Manual

General Information

General Rigid Pipe Installation Information

Installation steps (outline)

WARNING
Ensure that the entire venting system is protected from
physical damages. A damaged venting system may
cause unsafe conditions.
WARNING
The venting system is approved for indoor installations
only. Do not install the venting system outdoors.
IMPORTANT
Proximity to damp and salty marine environments directly
influences the service life of the boiler's exposed metallic
surfaces, such as the casing and fan housing. In such
areas, higher concentration levels of chlorides from
sea spray, coupled with relative humidity, can lead to
degradation of the exposed metallic surfaces mentioned
above. Therefore, it is imperative that boilers installed
in such environments not be installed using direct vent
systems which draw outdoor air for combustion. Such
boilers must be installed using room air dependent vent
systems; i.e. using room air for combustion. The indoor air
will have a much lower relative humidity and, hence, the
corrosion will be minimized.
Route vent pipe as directly as possible and with as few

bends as possible to the boiler.
Check proper location of gaskets in rigid PP(s) pipe

collars. (Only use supplied parts with the polypropylene
venting system.)
Apply water to lubricate the joint ends of the vent pipe
collar and if used, the air intake pipe collar.
Slide pipes into each other with a gentle twisting motion.

Condensate must drain from the flue pipe to the boiler.

Ensure a suitable gradient of at least 3º [approx. 2 in.
per 3.3 ft. (50 mm per 1 m)].
Use a hacksaw or sheet metal snips (for stainless steel)

to cut pipes to length (if necessary). Use a file to
smooth rough edges. Pipe must be round and not bent
into an oval shape.
IMPORTANT
When cutting pipes to length, debur and clean pipes.
12
CU3A Venting Systems Installation

Vent system manufacturers

The following Coaxial and PP(s) vent system manufacturers
may be contacted for assistance in designing the appropriate
venting system for Vitocrossal 300 CU3A boilers.
M&G / Duravent
www.duravent.com
*PolyFlue - Selkirk
www.polyflue.com
Z-FLEX US Inc.
NovaFlex Group
www.novaflex.com
* requires double pipe system with coaxial termination only.
For Vitocrossal 300 CU3A-45/57 (with boiler flue
termination 110 mm) the vent manufacturers M&G and
PolyFlue requires a transition adaptor.

Leak test (for coaxial venting systems only)

Viessmann recommends that the heating contractor perform
a simplified leak test during boiler start-up. For this purpose
it is sufficient to measure the CO
combustion air in the annular gap of the air intake pipe.
The vent pipe is considered sufficiently leak-proof if a CO
concentration in the combustion air no higher than 0.2%
or an O concentration no lower than 20.6% is measured
2
relative to a starting O concentration of 20.9%.
2
If higher CO values or lower O
2
inspect the venting system thoroughly.
Continuous short cycling of the boiler can indicate a leaking
venting system.
Note: The boiler's flue gas termination has an integrated
port for flue gas measurement.
Centrotherm InnoFlue
www.centrotherm.us.com
ECCO Manufacturing
www.eccomfg.com
concentration of the
2
values are measured,
2
2