OPTIONAL FEATURES
HeatNet Control REV 1.38-1
Page 19
Setting up base loading
The base load boiler is controlled using a set of contacts to
enable it (location J4). Enabling/Disabling this relay contact
can be done using any combination of (3) qualifiers to start
the boiler and (4) to stop the boiler. These qualifiers are:
1.
Modulation %
:
a.
START menu item
: The relay contact will close
when the MOD % from the Master boiler exceeds
this value.
ADVANCE SETUP:BASE LOADING:
START>MOD
b.
STOP menu item
: The relay contact will open
when the MOD % from the Master boiler falls
below this value.
ADVANCE SETUP:BASE
LOADING: STOP<MOD
If the
START>MOD
value is set to a value
higher than the
ADVANCED SETUP:MOD-
MAX
:
all boilers
will be firing before this
modulation rate is reached. This will ensure
that all available boilers are firing before the
base load boiler relay is enabled.
c.
Setting the :
STOP<MOD
to a % value slightly above
the min fire rate % of the system will ensure that the
base load boiler will stop before the first condensing
boiler stops. This is due to the Modulation rate being
close to the min modulation rate before the water
temperature exceeds the top of the heating band.
2.
Outside Air Temperature
:
a.
START menu item
: The relay contact will close to
enable the boiler when the OA T read from the
Outside Air Temperature sensor (if Equipped) falls
below this temperature.
ADVANCE SETUP:BASE
LOADING: START< OA T
b.
STOP menu item
: The relay contact will open to
disable the boiler when the OA T read from the
Outside Air Temperature sensor (if equipped) rises
above this value.
ADVANCE SETUP:BASE
LOADING: STOP> OA T
If the OA T qualifier is used as the Start and
Stop qualifier, ensure that there is at least a few
degrees difference for hysteresis.
3.
Return Water Temperature
a.
START menu item
: The relay contact will close
to enable the boiler when the RET read from the
Return Water Temperature sensor (if Equipped)
falls below this temperature.
ADVANCE
SETUP:BASE LOADING: START> RET
b.
STOP menu item
: The relay contact will open
to disable the boiler when the RET temperature
read from the Return Water Temperature
sensor (if Equipped) rises above this
temperature.
ADVANCE SETUP:BASE
LOADING: STOP< RET
4.
FIRST
:
a.
STOP menu item
: The relay contact will open
to disable the boiler when the temperature
exceeds the heating band. This gives the result
of stopping the Base Load boiler First. Default
setting.
Delay Time
The DELAY TIME is also included to hold off starting the
boiler until the delay time is met. Once the start condition
qualifier term is met, the DELAY TIME will start counting
down. When the time expires, the base load relay contacts
will close.
ADVANCE SETUP:BASE LOADING:DELAY
TIME
. It is adjustable in a range of: 0 to 60 minutes.
Base Load Failsafe
If there are no boilers available to fire (offline or faulted) and
there are no boilers in local override, and there is a call for
heat, The J4 Base Load relay will close. If a boiler becomes
available and needs to fire, the Base Load boiler will remain
firing until the temperature exceeds the band. This is provided
to keep the system from entering a no heat situation.
