IBC Technologies Inc.
32
VFC 15-150 and VFC 45-225
5.
Each of the boiler’s 3
Load
positions
can be configured for any type of
heating. VFC boilers are factory
shipped with default settings as
follows: Load 1 set as
Space
Heating
or
Reset Heating,
with
High
Mass Radiant Floor
set as the
terminal type; Load 2 as Set Point;
and Load 3 as DHW. The factory
defaults can be changed using the
Define Load 1-2-3
lines to reverse
the order, turn off a Load or do
whatever the installer desires.
6.
Once the appropriate
Loads
are set,
use the left-hand key to move back
to the
Setup Heating Loads
screen,
then move down to
Configure Load
1
(and hit enter).
7.
The screen will display the input
fields appropriate to the nature of
the load selected, e.g.
Design
Outdoor Temp
. for a
Space Heating
(or
Reset Heating)
load. Note: these
fields are pre-loaded with default
values that are to be altered to
reflect the desired parameters.
8.
For reset loads, the initial selection
to be made addresses the “emitter”
type – choises include H(high) Mass
Radiant, L(ow) Mass Radiant,
Baseboard, Air Handler etc. An
appropriate reset curve is called up
through this procedure. Reset loads
carry a default value for
Design
Outdoor Temp
. of -10°F (-23°C).
Raise or lower this as appropriate –
e.g. for Vancouver, use 19° to 25°F,
while for Edmonton -35°F would be
appropriate. Note: - for some users,
this adjustment may seem counter-
intuitive. Moving the setting toward
a colder design value will have the
effect of reducing the boiler’s target
temperature for any given weather,
because a given current condition is
relatively warmer than the
designated “coldest” day.
Moving down the screen, set the
Design Supply Temperature
– the
targeted temp. for circulating water
on the coldest day. For an in-slab
radiant floor this would typically be
125°F (50°C). For finned tube
baseboards typically driven at
180°F, try 160°F max. instead, to
promote combustion efficiency. For
air handlers, try running 20°F lower
than typically used. Of course, the
appropriate setting will depend on
the characteristics of the emitter and
the building but in general the VFC
modulating boiler’s large throttle
turndown will allow better average
temp. control, permitting lower
maximums.
9.
For Reset Loads, move down the
screen again to display more lines;