Viessmann VITODENS 100-W WB1B Series Installation And Service Instructions Manual page 20

Boiler Connections
Connections
Gas connection and piping (continued)
Fig. 17
Legend
A Gas connection
B Accessible manual gas
shutoff (factory supplied)
C Drip leg
IMPORTANT
Max. gas supply pressure: 14 "w.c.
WARNING
The gas supply piping must be leak
tested before placing the boiler in
operation.
CAUTION
Ensure that gas piping is large
enough for all appliances in the
residence. No noticeable gas
pressure drop in the gas line
must occur when any unit (or
combination of units) lights or runs.
20
(continued)
1. Refer to current CAN/CSA B149.1
or 2 in Canada. In the United
States, use the National Fuel
Gas Code ANSI Z223.1/NFPA 54,
as well as local codes for gas
piping requirements and
sizing. Pipe size to the boiler must
be determined based on:
- pipe length
- number of fittings
- maximum input requirements of
all gas appliances in the
residence.
IMPORTANT
Design piping layout in such a way
that piping does not interfere with
serviceable components.
2. Before connecting boiler to gas
line, install ground joint union,
capped drip leg and a manual
equipment shutoff valve.
Valves must be listed by a
nationally recognized testing
agency. Make boiler gas
connection as shown on the left.
Gas connection (NPT)..........∅ ¾"
3. Perform gas piping pressure
test as described in the following
subsection.
4. Identify shutoff valves as such
with a tab and familiarize operator
/ ultimate owner of boiler with
these valves.