IBC Technologies Inc.
30
VFC 15-150 and VFC 45-225
2.6.4 Temperature Setback
For heating loads declared as
Space
Heating
(e.g.with
Outdoor Reset)
and/or
DHW
(where a thermistor probe
is used), there are provisions for
entering temperature setback intervals.
During the setback period, the boiler
supply water temperature target is
adjusted from the pre-set fixed or
floating (with
Outdoor Reset
) levels.
There is a simultaneous movement in
the
Indoor Setpoint Temperature
or
DHW Tank Setpoint
, to yield a
consistent spread and avoid undesirable
cycling. Normally users would apply
this feature to achieve fuel savings
during night-or-away hours. It is also
possible to use the feature to set forward
(up) the temperature; this may be of use
for certain commercial applications
where short-term high temperature
DHW service is desired.
Up to 56 events / week can be
programmed for each eligible load – for
example, DHW can be set back twice
and returned (twice) each day. The
routine can be applied by specific day
(Mon-Sun).
The automated setback feature cannot
be applied to setpoint loads, including
DHW with simple aquastat control. This
is due to the lack of linkage with the
thermostat; setback without linkage
could lead to unacceptable cycling.
Access is via the
User Setup
screen.
2.6.5 Unoccupied Mode
Users can further reduce energy
consumption by switching the boiler to
the unoccupied mode during holidays or
other away periods.
While in the Unoccupied mode, the
DHW load is turned off, while Space
Heating loads for which Outdoor Reset
is activated will drop both the
circulating water and the indoor setpoint
temperature parameters to 50°F. Set
Point controlled loads are not adjusted
through this process, to avoid the
potential for boiler cycling as there is no
linkage with the relevant thermostat.
On the main
User Setup
Menu, select
"
Occupancy Status
", then toggle
between
Occupied
(top button) and
Unoccupied
(lower button) as desired.
2.6.6 Summer Shutdown
During the
Installer
set up process, a
cut-off level for outdoor temperature
can be selected - to curtail any further
space heating. This is typically used to
turn off an Outdoor Reset enabled load
once the outdoor temperature reaches a
threshold level e.g. 60°F. The load will
be automatically reactivated once the
weather returns to levels below the
selected threshold. Use of this feature
with a value 5° - 10°F below the
Indoor
Setpoint Temperature
is strongly
recommended to avoid short cycling of
the boiler during very marginal heating
conditions.
From the main Installer Setup Menu,
select "
Heat Load Configuration"
, then
"
Configure Load
(use the load number
tagged as Space Heating
)", and drop down
to "
Summer Shutdown
". Press
Enter
to
select, then use the keys to move the
threshold temperature to the desired
level, and press the centre key again to
record. The controller must receive a
valid signal from the
tekmar 070
outdoor sensor, supplied with the boiler,
to operate.
2.6.7 Remote / Slave Mode
Installers have the option of placing the
control of the boiler under an external
electronic controller (such as a
tekmar
265
). Connections are provided to
receive a 0-10vDC or 4-20 mA signal
for throttle management. The default
configuration is 4-20mA; to switch over
to 0-10V, remove the electrical box
corner cover to provide access to the
