Viessmann Vitoflex 300-RF Technical Data Manual page 28

Mechanical
Fire Protection
Back-burn safeguard for the fuel supply system
The fire extinguishing system for the conveyor auger and
the down pipe depends on specific requirements (location,
size of the fuel storage site, material, pressure conditions
and regulations), these being accessories to the scope
of delivery ordered from Viessmann according to their
descriptions.
Automatic triggering system for the fuel supply system
Approved in part as a variation to the shut-off valve in
pressure-less fuel storage units.
Slide valve
The slide valve is approved in pressure-less fuel storage
units and is a suitable safeguard against back-burn.
The slide valve is optional and closes in case of standstill,
danger of back-burn, or power failure, with the help of a
spring return motor.
IMPORTANT
We recommend installing a rotary valve for the Vitoflex
300-RF Rotating Combustion System. In addition to being
a safeguard against back-burn, this will also prevent any
penetration by air leaking in via the in-feed auger.
Rotary valve
The Rotary valve is optional and used if remnant wood
is moved into fuel storage spaces with blowers, then, in
order to reduce pressure applied, at least one rotary valve
is necessary to reduce pressure between the fuel storage
unit and the boiler. The rotary valve is suited to reduce
pressure and at the same time is considered a suitable
safeguard against back-burn.
Max. overpressure allowed in fuel storage unit:
+500 Pa (+2.00 in. wc).
Max. negative pressure allowed in fuel storage unit:
+0 Pa (+0 in. wc).
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(continued)
Double rotary valve with pressure compensation system
If, due to special circumstances, any mechanically
produced negative pressures or extraordinarily high
overpressures are expected in the fuel storage unit, then
two rotary valves must be installed in the material transport
route according to the respective project plan with a
pressure compensation line to the outdoors.
Max. overpressure allowed in fuel storage unit:
+3000 Pa (+12 in. wc).
Max. negative pressure allowed in fuel storage unit:
-3000 Pa (–12 in. wc).
IMPORTANT
The supplier of the silo must confirm the maximum
weight that is to be expected on the rotary valve.
The rotary valve below the silo extraction system can
become leaky due to wear of the sealing elements or
through large pieces of wood that cannot be conveyed.
This leakage can make it possible for low-temperature
gases to flow back from the boiler into the silo.
A smoke alarm must be installed between the rotary
valve and the silo extraction system, which, when
triggered, will disconnect the system and create negative
pressure in the silo.
Down pipe
A vertical drop-off section interrupts the connected line
of burning material.
Fire protection for fuel storage space
Viessmann does not provide fire protection for the fuel
storage space.
IMPORTANT
The local building codes and regulations must be followed
by the heating contractor.
Vitoflex 300-RF Technical Data