Connections
21
Water Side Connections
Installation Instructions
Divicon Station
This boiler is designed for closed loop,
forced circulation heating systems only.
1. Flush heating system thoroughly
(particularly with exis ting syste ms
which have been in operation for
years).
2. Attach all four 1½” NPT adaptors
and gaskets (Installation Fittings
Package) to the supply and return
welded non-NPT nipples on boiler.
Do not connect system piping
directly to supply and return nipples.
Cap set of supply and return
connections if not used.
3. Connect heating circuits.
(Two heating circuits may be
connected).
Do not connect the s y s tem return to
the safety return
.
4. Mount supplied reducer fittings
(Installation Fittings Package) on
safety return connection
.Sizes:
VB2-18 to -40 1“ to
3
/
4
“.......................
VB2-50 to -63 1
1
/
2
“to
3
/
4
“...................
We recommend the installation of a
spring-loaded flow-check v alve in
heating circuits without mixing valve s.
This serv es to avoid uncontrolled
gravity circulation of heat into the
heating syst em during prioritized DHW
production, or during summer months.
5167 404 v1.9
Safety supply, for pressure relief valve and air vent (NPT) ∅ 1“.....................
Boiler water supply (non-NPT) ∅ 1
1
/
2
“......................................................................
Boiler water return (non-NPT) ∅ 1
1
/
2
“.......................................................................
Safety return, for precharged expansion tank, boiler drain
and automatic feed (NPT) VB2-18 to -40 ∅ 1“
......................................................
VB2-50 to -63 ∅ 1
1
/
2
“...................................................................................................
Gasket
Connect this end using gasket to non-NPT threads
of welded supply and return boiler nipples
1
1
/
2
“ N PT male threads
IMPORTANT
CAUTION
Failure to flush the heating sys tem
could cause system sludge to settle
in the boiler, causing overheating and
failure. This type of failure is not
covered under warranty.
IMPORTANT
The boiler warranty does not cover
leaks resulting from corrosion caused
by the use of underfloor plastic tubing
without an oxygen diffusion barrier.
Such sys t ems must have the
non-oxygen diffusion barrier tubing
separated from the boiler with a heat
exchanger. Viessmann recommends
the use of underfloor plastic tubing
with an oxygen diffusion barrier.
CAUTION