OPTIONAL FEATURES
HeatNet Control V3 2.x
Page 45
sensor‘s temperature drops below the DHW Se
Lower Diff). The boiler will stop space heating (if running)
and switch to DHW heating. The DHW pump/valve will be
engaged and the water temperature in the tank will be
maintained by the boiler at the DHW setpoint. Once the tank
temperature exceeds the Se Upper Diff temperature,
DHW heating will stop and the pump/valve‘s post purge
will start.
LOCAL DHW TANK
MEMBER
Tank Sensor
LOCAL DHW TANK
MASTER
Tank Sensor
Main Heating Loop
LOCAL
LOCAL
DHW
DHW
LOCAL DHW Simplified Drawing
When a tank‘s temperature sensor is connected directly to a
boiler and the
DHW BOILER?
is set to
LOCAL.
The
boiler will go offline from HeatNet and service the DHW
needs of its local tank. If the boiler is running in space
heating mode, then the ―SHARING?‖ setting may be used
to determine how, or if, to shut down before starting a DHW
cycle. When the DHW cycle is complete (includes the post
purge time of the DHW pump), the boiler will go back
online with HeatNet and become available to fire.
During a DHW cycle the DHW setpoint will be loaded
along with the UPPER and LOWER DHW DIFF. Also, the
ADVANCED SETUP: DISTRIBUTED CTRL:
MASTER TYPE:
is set to
AUTO.
When a 10k Type II sensor is used with this method, the OR
OVR input functions as and enable/disable. This allows the
DHW heating function to be enabled or disabled much in
the same way as the Heat Demand input for space heating.
When using this method, a DHW band is also available by
scrolling through the status screens. Press the DOWN arrow
key when SYSTEM SET is displayed. 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.
23.
Connect a
10k thermistor from the DHW tank‘s sensor
well to J10B terminals on any boiler. Wire a pump or
valve from the DHW pump or the System pump
(normally open) relay contact to control flow of the
heating water into the tank‘s coil or system loop.
The System pump will always be enabled as long as the
Heat Demand input is closed and the
SETUP:
DOMESTIC HOT WATER:DHW PRIORITY
is set
to
NO.
The DHW pump will be enabled whenever
there is a DHW call for heat.
A DHW call for heat is when the DHW temperature is
below the (DHW SETPOINT – LOWER DHW DIFF)
or when the DHW temperature is below the (DHW
SE UPPER DHW DIFF) and boilers are
firing. After a DHW call for heat ends:
A.
The pump will remain on during a post purge
pump cycle until the post purge timer expires.
24.
Next, enter the
DOMESTIC HOT WATER
menu on
the Master boiler. When prompted for
DHW
BOILER?
, enter
LOCAL
.
25.
Change the
DHW SETPOINT
to the desired target
temperature of the water in the tank. Once the control
determines there is a call for DHW, the DHW
SETPOINT is loaded and the boiler will target the
setpoint.
26.
Now, change the
DHW LOWER DIFF
to the desired
temperature (DHW SETPOINT – LOWER DHW
DIFF) below which boilers are to be added. This setting
corresponds to the minimum water temperature
required in the tank. DHW heating will be initiated
when the DHW tank‘s water temperature is below the
temperature (DHW SETPOINT – LOWER DHW
DIFF).
How long the temperature of the tank stays below the
temperature (DHW SETPOINT – LOWER DHW
DIFF))
is used to determine when boilers are started
along with the ADD BOILER DELAY TIME.
27.
Next, change the
DHW UPPER DIFF
to the desired
temperature (DHW SE UPPER DHW DIFF)
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 DHW DIFF). Setting the SHED BOILER
DELAY TIME = 0 will shut off all boilers immediately
once the (DHW SE UPPER DHW DIFF) is
exceeded.
28.
Press the DOWN arrow key again to position the
cursor beside the menu item
DHW PRIORITY?
.
Setting this value to YES will turn OFF the
system pump when the DHW mode is active
(when the DHW pump is on). Setting this value
to NO leaves the system pump on.
29.
Press the DOWN arrow again and the menu item
POST PURGE
should appear. This is the time
that the DHW pump relay remains energized after
the DHW SETPOINT has been satisfied.
A. The pump will remain on during a post
purge pump cycle until the post purge timer
expires.
Summary of Contents for HeaetNet V3 KN-10
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