IBC V-10, Manual, Page: 89 / 103

11.0 Definition of terms
Term Definition
Add Level
(%) Sets the relative ouput level at which an idle boiler fires up. This is a percent of the
maximum firing rate of the lead boiler – on a 40-399 G3, for instance, a value of 60
would correspond to an output of 399 x 60/100 = 239. Note that this value must be at
least 10 higher than the Drop Level (%), which will be adjusted to satisfy this if Add
Level (%) is changed.
Aquastat
Control Device used in hydronic heating systems for controlling water temperature. Typically
used to manage domestic hot water temperature in an indirect water heater.
BACnet A Data Communication Protocol for Building Automation and Control Networks - A
protocol that provides information about a boiler’s heating, ventilating, and air
conditioning control (HVAC), lighting control, access control, and fire detection.
Boiler Pump
Enables you to shut off the Boiler Pump (primary loop pump) while a load is running.
The load pump must be piped (series piping) to ensure adequate flow through the boiler
without needing the Boiler Pump to provide flow through the heat exchanger.
When you set the Boiler Pump to "Off" a warning message appears as a reminder. If
the load is a radiant floor, we strongly recommend using primary or secondary piping
and leaving the Boiler Pump set to "On".
Boiler Pump
Purge Time
(Site
Settings) Adjustable independently of the four load pumps. Many installations use a primary
(boiler) loop. We recommend that the boiler pump operate for 3 – 5 minutes after all
calls for heat have been satisfied.
Boiler
Turndown A ratio that compares the full maximum boiler heat output (high fire) to the minimum
level of heat output (low fire).
Call for Heat A call for heat could be: The thermostat is indicating that room temperature is below
the thermostat setting. An Aquastat calling for DHW. The tank sensor calling for
DHW.
Classic-DDC
control Involves separate dry-contact calls and throttle control signals to each boiler from
external DDC. (Not generally recommended.)
Cycles Running tally of the number of calls for heat that a load has received in the last 24
hours. Fewer cycles per day = better efficiency.
Delta T Difference between the supply water temperature and the return water temperature.
Drop Level
(%) Sets the relative output level at which a firing boiler will be shut down as a percent of
the maximum firing rate of the master boiler. Note that this value must be at least 10
lower than Add Level (%), which will be adjusted to satisfy this when Drop Level (%) is
changed.
DSP Daylight Standard Pacific - time zone update.
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11.0 Definition of terms