Viessmann VITOFLEX 300-UF Operating Instructions Manual page 8

Introductory information
Appliance description
N
M
L
Fig. 2
Safety heat exchanger
A
Flame tube
B
Heat exchanger
C
Flue outlets
D
Up to 720 kilowatts: 1 flue outlet, centre
From 950 kilowatts: 1 flue outlet, left or right-hand
side (alternative flue outlet is closed off)
Drain outlet
E
■ Control unit
The system control unit controls the combustion sys-
tem with all associated components.
Fuel supply
■
The feed system transports fuel into the combustion
retort from the side. A feed screw conveyor is instal-
led at the side for this purpose.
■ Infeed grate
Burning fuel is pushed out of the combustion retort
onto the sloping grate and from there onto the infeed
grate. The infeed grate has moving parts which can
transport the spent fuel (ash) towards the ash
removal area.
■ Ash removal
The infeed grate pushes ash into the ash trough.
From here, an ash removal screw conveyor trans-
ports the ash out of the combustion chamber.
8
(cont.)
A B A
K
C
D
E
F
G
H
Ignition fan connection
F
Connection, primary air fan 2
G
Drive, infeed grate
H
Feed screw conveyor
K
Ash removal screw conveyor
L
Infeed grate
M
Ash collector trough
N
■ Boiler safety equipment
The heat exchanger contains a high limit safety cut-
out and water pressure switches (positive and/or
vacuum pressure).
The combustion chamber is fitted with positive pres-
sure limiters.
In the fuel supply area, safety limit switches are
installed on the inspection covers.
Burn-back protection
■
Burn-back protection on the feed screw conveyor is
provided either by a shut-off gate valve or a rotary
lock valve. The type of locking device used depends
on the position and size of the fuel store and the
pressure conditions in the fuel transport system. An
extinguishing device is also installed which floods the
feed screw conveyor with water when a selectable
response temperature is reached.