Specifications

SARIgas Zoom Z – ZF Page 16
Rev.0
ROOM VENTILATION FOR NATURAL DRAUGHT BOILERS, TYPE “B
11BS
” mod. Z 420A - Z 520A
mod. ZF 420A ZF 520A (Class B 22 appliances) for installation refer to pages 14,15.
These boilers must be installed in suitable environments, which guarantee the right level of combustible air
intake; they must be connected to a exhaust flue outlet pipe.
For ventilation, refer to local legislation.
B
11BS
Boilers are the open chamber type, designed for connecting to exhaust pipe for the combustion products to the
outside of the room: combustible air is taken directly from the room where the boiler is installed.
Air vents on the outside walls of the boiler room:
- Must have a free net air passage that conforms to current legislation in size;
- Must be made in such a way that the inside and outside vents cannot be covered or blocked.
- Must be protected with grids or wire net, etc., but the protection must not reduce the size of the passage as indicated
above.
- Correct aeration can be obtained from several vents, as long as the total net air passage corresponds to current
legislation.
- If the vents cannot be made near to the floor, the section of the vent opening must be increased, as indicated in the
specific standards.
- If there are other elements in the boiler room that draw in air to work, the section of the vent opening must be
adequately increased.
- If the boiler is installed in a room that contains a cooking hob without safety device, as it does not use an open flame,
the ventilation vents must be increased.
- The suction hood is always to be considered as an electric fan.
- An open fireplace must have its own air draft, otherwise gas appliances of the B 11BS type cannot be installed in the
room.
If an external opening cannot be made, air flow from an adjacent room is allowed as long as the room is not in
negative pressure due to the presence of another draft (fireplace or stove) or another suction appliance, and it is not
used as a bedroom.
Zoom Z 420A – Z 520A boilers are fitted with a manual reset flue gas safety thermostat which, if there is poor draft in
the flue pipe, permanently blocks the gas flow to the main burner. Therefore before beginning installation check the
working features (flue pipe draft, "flue"), the sizes, such as the ∅ of the flue opening, and the inside section which must
be adequate to support the output of the boiler.
If the flue safety thermostat triggers while the boiler is working, turn off the boiler and the electric supply to the
boiler, remove the blocking clamp of the electric plug connected to the thermostat (Fig. 20), press the red thermostat
rearm button with your finger. Reconnect the previously removed plug, replace the previously removed clamp and carry
out a new flue draft test.
IMPORTANT: Under no circumstances must the flue safety thermostat be blocked, interfered with or removed from its
original position (see Fig.20).
ATTENTION:
To ventilate the rooms fitted with mod. ZF 420A, ZF 520A
boilers, with configuration B
22,
refer to the specific
Standards for "B" type appliances.
Follow the instructions given on pages 14-15 to install the
flue pipes.
Fig.20