Installing Boiler Safety Devices - Viessmann Vitocrossal 300 CU3A 26 Installation Instructions Manual

Boiler Connections
Connections
(continued)
Standard safety header configuration
Optional safety header configuration
Legend
A Reducing coupling, 1a in. x ¾ in.
B Long nipple, ¾ in. x 4 in.
C Tee, ¾ in.
D Bushing, ¾ in. x e in.
E Air vent
F Street elbow, ¾ in.
G Short nipple, ¾ in. x 1b in.
H Pressure relief valve, ¾ in. 30 psig
I Street elbow, ¾ in. (field supplied)
16
Vitocrossal 300 CU3A 26 to 199 Installation

Installing boiler safety devices

1. Apply sufficient amount of pipe sealant to both ends
of all pipe fittings B,D,F and G and install onto
coupling A and tees C.
2. Install pressure relief valve H and air vent E and
tighten.
3. Install discharge pipe on pressure relief valve in such
a way that...
- the end of the pipe is not threaded.
- the pressure relief discharge pipe extends to a floor
drain and ends approximately 6 in. (150 mm) above
the drain.
Ensure that...
- there is no shutoff valve installed in the discharge pipe.
- discharge pipe diameter is not reduced.
- discharge is not piped to outdoors.
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.
Minimum connection diameters:
Pressure relief valve......................................¾ in.
Discharge pipe.............................................¾ in.
Piping to precharged expansion tank..(field supplied)