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P/N 42-9534 8/08 Copyright 2008 Hydrotherm
KN-SERIES GAS-FIRED DIRECT VENT CAST IRON BOILERS – CONTROL MANUAL
Menu item
Under . . .
Explanation
LIM->HALF RATE
AUX FUNCTIONS
HEAT EXCHANGER
Set this feature to YES to cause the control to automatically reduce the boiler fi ring rate to
one half the called for value if the temperature rise through the boiler exceeds the maximum
value desired. This maximum temperature rise is EXCHGR DELTA. NOTE: This function can be
used to prevent short cycling if the header temperature can drop quickly, causing the boiler
to try increasing boiler supply temperature to meet the apparent demand increase. Quick
header temperature drop can occur, for example, when boilers are equipped with slow-
opening valves — the valve begin to allow fl ow as they open, but the boiler can’t fi re until
they are fully open and make their end switches.
NOTE: DISPLAY — When this feature is enabled, the display will be diff erent from normal. In
RUN mode, the display will show “1/2 INPUT *” instead of RUN %. The “*STATUS” screen will
show “ADAPTIVE IN” over the START and STOP times.
SYSTEM CLOCK
Set the system clock (time, day of week, month, day and year) on start-up and after any
power outage to ensure the data log time stamp information will be accurate.
CONTROL
ADVANCED SETUP
DISTRIBUTED CTRL
This is not adjustable. It only displays that the control is a HeatNet (H-Net) control.
H-NET Master
ADVANCED SETUP
DISTRIBUTED CTRL
This is not adjustable. It will automatically say YES for the Master boiler and NO for a MEMBER
boiler. (The Master boiler is the boiler with a sensor connected to the SYS/DHW HEADER
terminals.)
H-NET ADDRESS
ADVANCED SETUP
DISTRIBUTED CTRL
Assign each MEMBER boiler a unique address, any value from 2 through 16.
The Master boiler H-NET address is automatically set to 255. (The master boiler is automatically
recognized because it is the one with a sensor wired to its SYS/DHW HEADER terminals.)
MODBUS ADDRESS
ADVANCED SETUP
DISTRIBUTED CTRL
This is used only when the boilers are regulated by a building management system, using
MODBUS, BACNET or LONWORKS. Assign each member boiler AND the Heat Net master
boiler a unique address, any value from 1 to 247.
ADD BOILER DELAY
ADVANCED SETUP
MODULAR BOILER
This is the minimum wait time before an additional boiler can fi re when called on by the
master boiler control.
MODULATE DELAY TIME
ADVANCED SETUP
MODULAR BOILER
The boiler will remain at minimum fi re when fi rst starting until this amount of time has elapsed.
MOD MAX - LAST FIRE
ADVANCED SETUP
MODULAR BOILER
This sets the maximum fi ring percentage for boilers during times that some boilers are not
fi ring. It limits input of the boilers to keep them as effi
cient as possible. Once all boilers are
started (during high heat demand periods), this restriction is removed, and all boilers can fi re
up to maximum input. Once any boiler is dropped offl
ine, the restriction is applied again.
ROTATION
ADVANCED SETUP
FIRING MODE
Select the rotation method.
TRUE ROTATION (or TRUE RUNTIME ROTATION) attempts to fi re all boilers an equal amount
of time.
FIRST ON FIRST OFF jogs between boilers to balance usage.
LAST ON FIRST OFF maintains the same rotation sequence at all times.
Master FIRST
ADVANCED SETUP
FIRING MODE
Set this to “ON” to always start the master boiler fi rst, regardless of the rotation scheme
selected.
SENSOR#
ADVANCED SETUP
SENSORS
The HeatNet control can be connected to up to six sensors: OUTSIDE, SUPPLY, RETURN
HEADER, and two user-selectable inputs (number 5 or number 6).
Table 9
Setup menus — parameter explanations (continued)
Control menus and adjustments
(continued)
Control menus and adjustments
(continued)
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