Safety Connections And Pressure Testing; Installing Safety Devices On The Boiler - Viessmann VITODENS 100-W WB1B Series Installation And Service Instructions Manual

Boiler Connections

Safety Connections and Pressure Testing

Installing safety devices on the boiler

Fig. 21
Legend
A Pressure relief valve (30 psig),
¾" NPT
B Brass nipple, length 2" x ¾"
C Drain valve connection, ¾"
D Tee, ¾"x¾"x¾"
E Brass nipple, length 3" x ¾"
F Tee, ¾"x¾"x¾"
L Boiler supply connection
24
1. Remove loosely preassembled
combination pressure relief valve
and drain valve assembly.
2. Apply sufficient amount of pipe
sealant to both ends of all pipe
fittings B, C, and E, and install
onto tees D, F.
3. Install pressure relief valve A and
tighten.
4. Install discharge pipe on pressure
relief valve in such a way that...
the end of the pipe is not
g
threaded.
the pressure relief discharge
g
pipe extends to a floor drain and
ends approximately 6"/150 mm
above the drain.
Ensure that...
there is no shutoff valve
g
installed in the discharge pipe.
discharge pipe diameter is not
g
reduced.
discharge is not piped to
g
outdoors.
Minimum connection diameters:
Pressure relief valve.....................¾"
Discharge pipe ........................... ¾"
Piping to precharged
expansion tank............................¾"
IMPORTANT
Install the (approved) factory supplied
pressure relief valve.
Removal of air from the system
must occur via use of air vent(s) in
the system supply. To ensure the
boiler can be purged of all air, ensure
supply/return water lines do not
contain restrictive piping where air
could be trapped.
WARNING
Do not install an isolation valve
between boiler and pressure relief
valve.
The discharge pipe for the pressure
relief valve must be oriented to
prevent scalding of attendants.
Pipe pressure relief valve discharge
pipe close to floor drain. Never pipe
discharge pipe to the outdoors.
Low water cut-off
A low water cut-off may be required
by local codes. If boiler is installed
above radiation level, a low water
cut-off device of approved type (field
supplied) must be installed in all
instances. Do not install an isolation
valve between boiler and low water
cut-off (see subsection entitled "Boiler
with low water cut-off" on page 35 in
these instructions).