OPTIONAL FEATURES
HeatNet Control V3 2.x
When using this method, a DHW band is also available in
the Home screen. The space heating band will be displayed
on the left and the DHW Heating band on the right. The
bands will operate in a split screen view.
When using MASTER TYPE:
MIXED (Combination)
,
The Master may control DHW and Space Heating needs. If
the Master goes down or loses communication with the
Member, a Failsafe mode is available to provide temporary
heat.
The DHW Failsafe mode is active when a Member boiler‟s
SETTINGS: FAILSAFE MODES:H-NET
COMMUNICATIONS LOST: is set to
ON
. When this is set
to on, normal DHW heating using the OR OVR or DHW
sensor is disabled, even though there may be a DHW call on
one of these inputs.
When the Master Boiler‟s communication is lost, and after
10 minutes of not being restored, the DHW inputs become
active. The boiler now enters a stand-alone mode. The Heat
Demand on that boiler becomes active and not only runs to
provide failsafe space heating, but DHW heat as well. The
STATUS screen will display and H-NET LOST. If a
thermostat is used, the boiler will run to Method 5A until the
thermostat input removes the DHW call. If a DHW
temperature sensor is used, the boiler will modulate to
maintain tank temperature. The DHW Call always has priority
over space heating. A dual 10k sensor is available that can be
wired from one tank to two boilers.
DHW TANK
MEMBER
Tank Sensor 2
MASTER
Tank Sensor 1
Main Heating Loop
LOCAL
LOCAL
DHW
Ensure that the Member boiler‟s Damper and System pump
control are configured correctly with the assumption that the
Master is not powered. Also ensure that any other System settings
related to outside air temperature sensing and system interlocks
are set to provide safe operation.
Example: Failsafe Sensor Simplified Drawing
The above example uses (2) boilers. The Master controls the
Space and Domestic needs. Failsafe control is provided by
wiring the Member boiler to the tank sensor (dual sensor is
optional) and any other system control needs the Member
may require in its backup role. Then one of the local DHW
control methods can be used to implement DHW heating.
One advantage to this configuration is that a BMS can
control the system through the Master. It can also monitor
system status through a central location (Master boiler) by a
BMS, or HeatNet Online. This failsafe method can also be
used in the
Combination DHW/Space Heating Simplified
Drawing.
Set up the Master boiler first:
1.
Connect a
10k thermistor from the DHW tank‟s sensor
well to J10B terminals on the MASTER, and connect a
Header Sensor to the SYSTEM HEADER input. Wire
any pump or valve from the DHW Pump relay‟s
(normally open) contact to control flow of the heating
water into the tank‟s coil or DHW loop.
2.
Now, set the
SETTINGS: DISTRIBUTED
CONTROL: MASTER TYPE:
to
MIXED
(Combination)
. This setting informs the HeatNet
control that (2) PIDS are to be used to control DHW
and space heating.
3.
There are two
MODULAR BOILER menus
, one for
space heating and one for DHW heating. These (2)
menus appear when the
SETTINGS: DISTRIBUTED
CONTROL: MASTER TYPE
is set to
MIXED
(Combination)
. The (2) Modular boiler settings are
located in the
SETTINGS: MODULAR BOILER:
menu. Normally, there is only one, but with (2)
independent PIDs, the (2) heating setpoints may behave
differently due to their loads or for other various
reasons. These allow for separate
ADD, SHED,
MODULATE DELAY TIME
, and
MODULATION
MAXIMUM
settings for DHW and space heating.
4.
Next, enter the
SETTINGS:
DOMESTIC HOT
WATER
menu. When prompted for
BOILER MODE
enter
OFF
.
5.
Change the
DHW SETPOINT
to the desired target
temperature of the water in the tank/ or DHW loop.
Once the control determines there is a call for DHW
heat, the DHW PID will target this SETPOINT.
6.
Now, change the
LOWER BAND
to the desired
temperature (DHW SETPOINT – LOWER
BAND) below which boilers are to be added.
This setting corresponds to the minimum water
temperature required in the tank. DHW heating
will be initiated by starting boilers when the
DHW tank‟s water temperature is below the
temperature (DHW SETPOINT – LOWER
BAND).
7.
Next, change the
UPPER BAND
to the desired
temperature (DHW SE UPPER
BAND) above which boilers are to be shed. This
setting is the maximum tank temperature. Setting
the SHED BOILER DELAY TIME correctly will
limit the maximum tank temperature to the
(DHW SE UPPER BAND). Setting
the SHED BOILER DELAY TIME = 0 will shut
off all boilers immediately once the (DHW
SE UPPER BAND) is exceeded.
8.
Change the DHW priority menu item
PUMP
PRIORITY.
Setting this value to
YES
will turn OFF
the system pump when the DHW mode is active.
Setting this value to
NO
leaves the system pump on.
43
Summary of Contents for KN-10
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