Gas Piping; Gas Pressure - Orifice Sizes - Viessmann Vitogas 050 ECD Series Installation & Service Manual

The gas ignition system and components must be protected
from water (dripping, spraying, rain etc.) during appliance
operation and service (circulator replacement, control
replacement, etc.). If boiler has been underwater, all electrical
parts must be replaced.
Pressure relief valve
The pressure valve supplied with this boiler must be installed.
Install a pressure relief valve according to Figs. A, 4, 5b.
A discharge pipe of the same diameter or larger as the pressure
relief discharge opening must be rigidly installed directly onto the
pressure relief valve. The discharge should extend to the floor
drain and end approximately 6˝ above the floor. The discharge
pipe end must not be threaded. Do not pipe discharge outdoors.
Warning:
Never cap or plug pressure relief valve opening or
discharge pipe. Never install shut-off valve between
boiler and pressure relief valve. Failure to heed this
warning can cause explosion resulting in property
damage, severe personal injury, or loss of life.
If pressure relief valve is discharging frequently, locate source
of problem and correct. Significant amounts of make-up water
will cause mineral deposits in boiler which may lead to failure.
This type of failure is not covered under warranty.
Follow instructions supplied with pressure relief valve.
Caution:
Discharge piping of pressure relief valve must be installed so
there will be no danger of scalding personnel.
Boiler is standard equipped with 30 psig ASME-rated pressure
relief valve. This 30 psig pressure relief valve may be
exchanged at the job site with a 50 psig ASME-rated pressure
relief valve only by strictly observing the minimum relief valve
capacity in lb/h marked on the nameplate. The maximum
allowable working pressure is 50 psig.

Gas piping

Before connecting gas boiler to gas line, install main gas shut-
off valve, union, and capped drip leg (see Fig. 6).
Size gas supply piping to boiler according to local utility
requirements.
Identify the main shut-off valve as such with a tag and
familiarize owner of boiler with this valve.
Support piping by proper suspension method. Piping must not
rest on or be supported by boiler.
Testing – gas pipe
The boiler and its gas connection must be leak-tested before
placing the boiler in operation. Use only the gas stated on the
boiler rating plate.
The boiler and its individual shut-off valve must be
disconnected from the gas supply piping system during any
pressure testing of that system at pressures in excess of
1
⁄ psig (3.5 kPa).
2
12
Manual gas
shut-off valve
Ground
joint union
Drip leg
Fig. 6
Gas pipe installation
The boiler must be isolated from the gas supply piping system
by closing its individual manual shut-off valve during any
pressure testing of the gas supply piping system at a test
pressure equal to or less than
Unions and manifold have been factory-tested. Leak test must
be repeated during initial trial operation of burner by
mechanical contractor.
Never check for gas leaks with an open flame. Use approved
spray liquid or soap water solution for bubble test.
Gas pressure – Orifice sizes
Natural Gas
Minimum gas valve inlet pressure
Maximum gas valve inlet pressure
Propane Gas
Minimum gas valve inlet pressure
Maximum gas valve inlet pressure
Flame
roll-out
switch
13 mm
socket
Fig. 7
Gas manifold removal
1
⁄ psig (3.5 kPa).
2
4.5˝ w.c.
14˝ w.c.
12˝ w.c.
14˝ w.c.
Burner tubes
Manifold
attachment
screws
(2 per side)
Pilot
Manifold
burner
pressure test
port