Piping - Biasi Riva Plus Installation & Operation Instructions

14.

Piping

All external piping components are to be supplied by the installer. It is very important to use a
Primary Secondary piping scheme when an external circulator will be used. Also, when the
boiler is piped in a primary secondary manner, it is necessary to us the central heating ow
restrictor supplied with the boiler. The ow restrictor ensures that there will be enough back
pressure to make the central heating ow switch in a low head loss piping system like primary
secondary.
Installation of ow restrictor: The ow restrictor is installed inside the pipe tail that
There are two methods for accomplishing a Primary Secondary piping system. The rst is
to use two closely spaced tees for the boiler supply and return. An example is shown below
in Figure 14.1. The run legs should be sized so that there is no excessive head loss on the
external circulator that is installed. In most circumstances 1 ¼" piping will be the best choice.
When the boiler is piped in this way, the external circulator will not have any hydraulic effect on
the Riva boiler. This is essential to ensure that the ow switch will operate properly.
The second method is a hydraulic separator. Hydraulic separators are available commercially;
however you can also construct your own. An example of a hydraulic separator is given in
Figure 14.2. It is important that the separator be at least 2" in size to ensure proper perfor-
mance.
1 ¼"
RIVA PLUS MANUAL
attaches to the boiler. Place the ow restrictor into the
gasket for the central heating supply pipe tail. Place the
gasket on the pipe tail so the ow restrictor seats into
the pipe tail. Then install the pipe tail onto the boiler.
Boiler
Supply
System
¾"
Supply
Boiler supply
¾"
System
supply
Boiler
Return
Must be less than 8"
1 ¼"
Boiler Return
No more than 8"
2"
At least 16"
System
Return
System
return
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