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This boiler is equipped with a feature that saves energy by reducing the boiler water temperature
as the heating load decreases. This feature is equipped with an override which is provided
primarily to permit the use of an external energy management system that serves the same function.
THIS OVERRIDE MUST NOT BE USED UNLESS AT LEAST ONE OF THE FOLLOWING
CONDITIONS IS TRUE:
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A. Overview
1. Honeywell R7910B Controller
The Honeywell R7910B Controller ("Control")
contains features and capabilities which help improve
heating system operation, and efficiency. By including
unique capabilities, the Control can do more, with
less field wiring, and fewer aftermarket controls and
components – improving the operation of both new
and replacement boiler installations.
2. Advanced Touch Screen Display
Home Screen
Boiler status and setup selections are available from an
easy to use LCD Touch Screen Display. In the event
of a fault condition the user is guided by "blinking"
touch buttons to Help screens that describe the problem.
Operation evaluation and problem-solving is enhanced
by historical capability including lockout history
records as well as boiler and circulator cycle counts
and run time hours.
3. Advanced Modulating Control
The Control modulates the boiler input by varying
the fan speed. As the fan speed increases, so does the
amount of fuel gas drawn into the blower. As a result,
a fairly constant air-fuel ratio is maintained across all
inputs. The Control determines the input needed by
looking at both current and recent differences between
the measured temperature and the setpoint temperature.
As the measured temperature approaches the setpoint
temperature, the fan will slow down and the input will
drop. The Control also utilizes boiler return water and
flue gas temperatures to adjust fan speed.
107774-01- 9/17
An external energy management system is installed that reduces the boiler water
temperature as the heating load decreases.
This boiler is not used for any space heating.
This boiler is part of a modular or multiple boiler system having a total input of
300,000 BTU/hr or greater.
XIII. Operation
IMPORTANT
4. HeatMatch
When the boiler is installed with a Sage Zone Control
Panel (Zone Control) into a multiple zone home the
Control uses a patent pending HeatMatch Software
to improve home comfort, increase component life
and save energy. The Control with the Zone Control
detects active (turned "On") zones, totals btu/hrs
expected and limits the boiler firing rate to "match"
actual home demand. Instead of simply firing to 100%
in response to a cold supply water temperature the
Control combines heat matching with supply water
temperature control. Additionally, as zones turn
"Off" maximum firing rate is immediately reduced
eliminating the need for supply water temperature to
first increase above setpoint. The result is longer run
times, dramatic reduction in boiler excessive cycling
and higher operating efficiency. A voiding extra cycling
saves customer fuel dollars (pre and post purge sends
heat up stack) and saves wear and tear on the boiler.
Lowering the boiler's firing rate saves fuel dollars by
increasing the amount of flue gas condensation, always
the goal of condensing boiler installations.
5. Built-in Safety Control
The Control includes safety controls designed to ensure
safe and reliable operation. In addition to flame safety
controls the Control includes supply water temperature,
differential water temperature, and stack temperature
safety limits and stepped modulation responses.
Boiler modulation is adjusted when required to help
avoid loss of boiler operation due to exceeding limits.
Additionally, the Control accepts the field installation
of optional auxiliary safety limits.
6. Outdoor Air Reset
When selected the modulation rate setpoint is
automatically adjusted based on outside air temperature,
time of day and length of demand (boost) settings.
Outdoor air "reset" setpoint saves fuel by adjusting
the water temperature of a heating boiler lower as the
outside air temperature increases.
Software
TM
101
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