System Design Considerations
10
VITOCROSSAL 300, CT3
System Design Considerations
Venting
The Vitocrossal 300 boiler is a category IV
positive pressure condensing boiler. Each
boiler must be vented individually.
Depending on the boiler return water
temperature, the flue gases in the boiler are
cooled down into the condensation or dew
point area of the flue gases. Where they exit
the boiler, they reach a relative moisture of
100%. The flue gas temperature is between
9°F and 27°F (5°C and 15°C) higher than
the boiler return water temperature.
Therefore, depending on the connected
heating system, the flue gas temperature
can be beween 77°F / 25°C and 200°F /
93°C. Due to the low flue gas temperature
and the resulting minute updraft conditions,
as well as the additional condensation of the
flue gases in the venting system, the vent
system must be properly designed and
suitable materials must be selected. The
chimney must be gas and water tight.
Use an AL29-4C® special stainless steel
venting system (UL/ULC/CSA listed for
category IV) for vertical venting of the
Vitocrossal 300 boiler.
The following manufacturers may be
contacted for suitable stainless steel
chimneys:
ProTech Systems Inc.
26 Gansevoort Street
Albany, NY
12202
Tel.: (518) 463-7284
Fax: (518) 463-5271
Toll free: 1-800-766-3473
Selkirk Metalbestos
Selkirk Canada Corporation - head office
375 Green Road
Stoney Creek, ON
L8E 4A5
Tel.: (905) 662-6600
Fax: (905) 662-5352
Toll free: 1-800-263-9308
Security Chimneys
Division of Security Chimneys Ltd.
2125 Monterey
Laval, PQ
H7L 3T6
Tel.: (450) 973-9999
Fax: (450) 973-2222
Toll free: 1-800-667-3387
Van-Packer Co. Inc.
302 Mill Street
PO Box 307
Buda, IL
61314
Tel.: (309) 895-2311
Fax: (309) 895-3891
Toll free: 1-888-877-8225
Exhausto CASV/CASI
Mechanical Draft System
Wesmech Technical Sales
50 Ronson Drive, Suite 160
Toronto, ON
M9W 1B3
Tel.: (416) 251-8990
Fax: (416) 251-8900
Toll free: 1-800-613-3789
Condensate and its disposal
During the operation of the boiler, the
amount of condensate to be expected can
be read from the diagram below.
The values given are approximate amounts
occurring under practical conditions. Not
included in the diagram is the amount of
condensate occurring in the vent pipe and
chimney system. The condensate from the
chimney system can be collected together
with the condensate from the heating boiler
and be disposed of into a floor drain. The
condensate will be between 3 and 4 on the
pH scale. If local building requirements
demand neutralizing the condensate before
disposal, contact Viessmann Manufacturing
Company Inc. for a correctly sized
neutralization tank. The treated condensate
will show pH values of between 6.5 and 9
and can then be disposed of into the waste
water system.
5
2
8
5
8
7
1
v
1
.9
Do not use PVC or CPVC material for
venting the Vitocrossal 300 boiler.
CAUTION
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Boiler water return temperature
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Note: The “amount of condensate” and the “flue gas temperature
gross” graphs are independent of each other.
