DHW METHODS
HeatNet Control V3
Page 51
This method is used to provide
combination space heating
and DHW heating.
The boiler may be standalone or in a
HeatNet configuration. It is meant to fire an individual
boiler in a DHW heating Priority mode when that boiler’s
local tank temperature has a call for DHW heat (tank
sensor’s temperature drops below the DHW Se
LOWER BAND). 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 BAND temperature, DHW heating will stop and the
pump/valve’s post purge will start.
When a tank’s temperature sensor is connected directly to a
boiler and the
BOILER MODE
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 BAND limits. Also,
the
SETTINGS: DISTRIBUTED CONTROL: MASTER
TYPE:
is set to
AUTO.
When a 10k Type II sensor is used with this method, the OR
OVR input functions as an 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 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.
1.
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 by the
MASTER as long as the Heat Demand input is closed
(In this example the Master is not a DHW boiler). The
DHW pump/valve will be enabled on the LOCAL
DHW MEMBER whenever there is a DHW call for
heat.
A DHW call for heat is when the DHW temperature is
below the (DHW SETPOINT – LOWER BAND) or
when the DHW temperature is below the (DHW
SE UPPER BAND) and boilers are firing.
After a DHW call for heat ends:
A.
The pump/valve will remain enabled during a
post purge pump cycle until the post purge timer
expires.
2.
Next, enter the
DOMESTIC HOT WATER
menu on
the MEMBER boiler. Go to
BOILER MODE
and
enter
LOCAL
.
3.
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.
4.
Now, change the
LOWER BAND
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 BAND).
How long the temperature of the tank stays below the
temperature (DHW SETPOINT – LOWER BAND)
is
used to determine when boilers are started along with
the ADD BOILER DELAY TIME.
5.
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.
6.
Change the
DHW PRIORITY
. Setting this value
to
YES
will turn OFF its system pump when the
DHW mode is active (when the DHW pump is
on). Setting this value to
NO
leaves the system
pump on.
7.
Now got to the
POST PURGE
menu. This is the
time that the DHW pump relay remains energized
after the DHW SETPOINT has been satisfied.
A. The pump/valve will remain on during a
post purge pump cycle until the post purge
timer expires.
8.
Now, go to the
USE SENSOR
menu and select
YES.
This will allow the boiler to control the
local tank or DHW loop temperature using the
DHW sensor. The upper and lower differential
temperatures will also be loaded.
9.
Got to
SHARING
and set it to
OFF
or
CYLE
if
the boiler is currently running in space heating
and needs to be shut down before starting up in
DHW
.
Summary of Contents for FUTERA XLF Series
Page 27: ...CONTROL METHODS HeatNet Control V3 Page 27 Figure 25 Base loading relay...
Page 67: ...WIRING CONNECTIONS HeatNet Control V3 Page 67 Figure 49 Jumper Dip Switch Locations...
Page 73: ...WIRING CONNECTIONS HeatNet Control V3 Page 73 Figure 57 Temperature sensors...
