To Next Page

To Previous Page

2-9

BOILER SYSTEMS AND OPERATION

VFC 15-150 - VFC 45-225 MODULATING GAS BOILERS

2.6.4 Variable Speed Pumping

This section reserved.

2.6.5 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xedoroating(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specic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.

2.6.6 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.

2.6.7 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

IBC VFC 45-225 Manual

Other manuals for IBC VFC 45-225