3.
2-stage speed regulation of
exodraft
chimney fan
3.1
Use
Area of use
• The EBC20 can be used as a 2-stage speed regulator for an
exodraft
chimney fan.
• The control system is intended for 1- or 2-stage atmospheric gas boilers.
• The EBC20 can control a chimney fan directly or indirectly via a frequency converter.
3.2
Method of operation
General function
• The EBC20 monitors chimney draft and disconnects the boilers in the event of errors (the alarmdiode on
the EBC20 will turn on).
• When the boiler thermostat demands heat, the chimney fan will start at max. voltage.
• When the monitoring system measures sufficient chimney draft, the burner is released, and voltage to the
chimney fan is regulated according to the setpoint for stage 1 (LOW).
• When stage 2 (HIGH) is activated, the EBC20 regulates the voltage to the chimney fan according to the set
point for stage 2.
• It is possible to set pre-purge and post-purge periods for the chimney fan.
• In the event of insufficient draft, the burner will be disconnected after 15 seconds. “Insufficient draft” is
draft less than the value set on the PDS during commissioning.
Step-up function
• The step-up function in the EBC20 prevents unintentional disconnection of the system on account of
changes in wind and weather conditions.
• The step-up function performs a stepped increase of the voltage as a result of protracted draft errors. In
principle, this can be repeated until maximum voltage has been reached.
3.3
Electrical connection
This work must be performed by a qualified electrical engineer, in accordance with locally applicable rules and
legislation.
The installation of the supply cable must be carried out in accordance with applicable regulations and
legislation.
The earth terminal (
) must always be connected.
Isolation switch
exodraft a/s
stresses that in accordance with EU’s Machinery Directive an isolation switch must be set up in the
fixed installation.
The isolation switch is not supplied by
exodraft
. Available as an extra.
3.4
Sample wiring diagrams
As a 2-stage speed regulator for
exodraft
chimney fans, the EBC20 can be connected to a range of different signals. The
following sections contain two sample wiring diagrams showing:
3.4.1 1 x 2-stage boiler, page 26
3.4.2 2 x 1-stage boilers, page 27
exodraft
recommends that you contact the boiler manufacturer for details of correct connection of the boiler
control system.
3002878-EBC20-UK
2-stage speed regulation •
25
