Gas Connection - Viessmann VITODENS 242-F Technical Manual

Design information
Recommended leads/cables
NYM 3 G 1.5 mm 2
– Power cables (also for accessories)
– DHW circulation pump
Interlock switch
Install an interlock for open flue operation if an extractor (e.g. cooker
hood) is fitted any room that is part of the interconnected combustion
air supply.
For this, the internal extension H2 (accessories) can be used. This
switches the extractors off when the burner is started.
Power supply for accessories
The power supply for accessories can be provided directly at the con-
trol unit.
This connection is switched by the system ON/OFF switch.
If the total system current exceeds 6 A, connect one or more exten-
sions directly to the mains supply via an ON/OFF switch.
Where the boiler is installed in a wet area, the power supply for acces-
sories must not be connected at the control unit.

Gas connection

Gas installations must only be carried out by a registered gas fitter
authorised by the relevant gas supply utility.
Connect and size the mains gas according to TRGI 2008 or TRF 1996
[or local regulations].
a Connect the mains gas according to ÖVGW-TR Gas (G1) and
the regionally applicable Building Regulations.
Maximum test pressure 150 mbar (15 kPa).
We recommend installing a gas filter to DIN 3386 into the gas line.
Thermally activated safety shut-off valve
According to paragraph 4, section 5 of the FeuVo 2008 [or local reg-
ulations], thermally activated shut-off equipment must be installed in
combustion equipment or in gas supply lines immediately upstream of
the combustion equipment. This equipment must shut off the gas sup-
ply if the external temperature exceeds 100 °C. The valves must iso-
late the gas supply for at least 30 min up to a temperature of 650 °C.
This is intended to prevent the formation of explosive gas mixtures in
the event of a fire.
Rated heat input Gas type
kW
16.7 Natural gas E
Natural gas LL
LPG
17.9 Natural gas E
Natural gas LL
LPG
24.7 Natural gas E
Natural gas LL
LPG
VITODENS
(cont.)
2-core min. 0.75 mm
– Extension AM1 or EA1
– Outside temperature sensor
– Vitotronic 200-H (LON)
– Extension kit for heating circuit with mixer
(KM BUS)
– Vitotrol 100, type UTDB (230 V)
– Vitotrol 200A
– Vitotrol 300A
– Vitocomfort 200
– Wireless base station
– Radio clock receiver
Connection values
3
m /h
1.77
2.05
1.89
2.20
2.61
3.04
2 4-core 1.5 mm
or
3-core 1.5 mm
wire
– Vitotrol 100, type UTDB-RF (230 V)
– Vitotrol 100, type UTA
Additional requirements when installing boilers operated with
LPG in rooms below ground level
According to TRF 1996 Vol. 2 – valid as of 1 September 1997 – an
external safety solenoid valve is no longer required when installing the
Vitodens below ground level.
However, the high safety standard derived from the use of an external
safety solenoid valve has proved to be valuable. We therefore recom-
mend the continued installation of an external safety solenoid valve
when installing the Vitodens in rooms below ground level. The internal
H1 extension (part of standard delivery) is required for the connec-
tion.
The gas shut-off valves supplied with the Vitodens are equipped with
integral thermally activated safety shut-off valves.
Gas connection line
The following table is designed to assist in the approximate sizing of
the on-site gas supply line.
For each 90° bend 1 m is deducted from the max. possible pipe
length.
Checking your calculations against TRGI and TRF [or local regula-
tions] is recommended.
Nominal diameter of the gas supply
pipe
kg/h DN 15
Max. possible pipe length in m
13
8
1.31 80
8
6
1.40 62
6
4
1.93 36
2
2
without green/yellow
DN 20 DN 25
60 –
40 127
– –
40 127
28 91
– –
28 91
21 68
156 –
VIESMANN
47
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