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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
WWS SETPOINT
OUTDOOR AIR
The boiler and its circulator shut down when the outside air temperature is above WWS
SETPOINT if outdoor air reset is enabled (ON). This requires an outdoor sensor when enabled.
The diff erential is 2°F; i.e., the boiler will shut off if the outdoor temperature is equal to or greater
than OUTDOOR AIR setting. The outdoor temperature must drop 2°F below OUTDOOR AIR
setting for the boiler to turn back on.
If the OA OVR input is closed, outdoor reset and warm weather shutdown are overridden. The
boiler will run at LOCAL/SYSTEM SETPOINT. This function can be used to operate the HeatNet
system at a fi xed temperature (equal to the LOCAL SETPT or SYSTEM SETPT), for applications
such as DHW heating.
LOW WATER
AT
HIGH OA TEMP
HI WATER
AT
LOW OA TEMP
OUTDOOR AIR
SET OA SETPTS
These temperatures determine the reset curve
for supply water temperature. High water at low
outside air means the design water temperature
for maximum load (at ODT, or outside design
temperature for the installation). The other end of
the reset curve is the low water temperature at
high outside air temperature. The low water
temperature is generally equal to room temper-
ature, meaning no heat input to the space
would occur below this outside air temperature.
POST PRG TIME
PUMP OPTIONS
SYSTEM PUMP
SYSTEM PUMP settings apply to a system pump if it is to be cycled by the HeatNet control.
Connect a relay or starter for the system pump to the SYSTEM PUMP terminals (J13). DO NOT
directly connect the pump motor with these terminals. They are for pilot duty only.
To prove system fl ow before boiler operation, install a fl ow proving switch across SYSTEM WTR
FLOW terminals (J11A). Place a jumper on these terminals if system fl ow proving is not used.
POST PRG TIME keeps the pump running for the specifi ed time after call for heat is completed,
allowing distribution of residual heat to the system.
WARNING — The system must be equipped with a bypass pressure regulator or other means
to prevent dead-heading if system valves close when call for heat is completed.
ALWAYS ENABLED
PUMP OPTIONS
SYSTEM PUMP
If enabled, the system pump remains on constantly. If pump is constant, DELTA TEMP and
POST PRG TIME have not eff ect.
NOTE: The system pump will shut down if outdoor air reset is enabled and the outside tem-
perature is above OA SETPOINT (summer mode operation).
WARNING — The system must be equipped with a bypass pressure regulator or other means
to prevent dead-heading if system valves close when call for heat is completed.
SUMMER PUMP JOG:
PUMP OPTIONS
SYSTEM PUMP
This option is available to prevent the pump from seizing during long idle periods. Enable
the option to have the system pump operated once per week (specify the day in setup). The
pump will cycle on at 12:00 AM on the day specifi ed. It will operate for a time equal to the
time set for POST PRG TIME.
WARNING — The system must be equipped with a bypass pressure regulator or other means
to prevent dead-heading if system valves close when call for heat is completed or during
summer or outdoor air shutdown.
DELTA TEMP ENAB
PUMP OPTIONS
LOCAL PUMP
The boiler pump can be set to run after boiler shutdown to distribute residual heat to the
heating system. Delta enable causes the boiler pump to run until the temperature diff erence
between boiler inlet and outlet is less than DELTA TEMP (see below). The pump will continue
to run an additional period after this for the amount of time specifi ed in PURGE TIME (below).
Table 9
Setup menus — parameter explanations (continued)
Control menus and adjustments
(continued)
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