CONTROL METHODS
HeatNet Control V3
Page 48
This method is for controlling DHW utilizing a 10k sensor
in the tank connected to
DHW TANK
(J10A, 9 & 10)
of
a Master boiler. This method is only available on the
Master boiler since its purpose is to override the setpoint.
This method requires a jumper input to the
OR OVR
(J12A 7 & 8),
which acts like an enable. The control
will
sense this closure and override the space heating setpoint
with the DHW setpoint when the DHW tank temperature
drops below the lower band of the DHW setpoint. All
boilers are started and stopped using the space heating
“Modular Boiler” settings.
SETTINGS: DISTRIBUTED
CONTROL: MASTER TYPE:
AUTO.
In this mode, the boiler will fire to the
DHW
setpoint. The settings for space heating will be used
except for the addition of the
Master Boiler
controlling the DHW pump/valve.
1.
Wire the 10K Tank sensor to the Master on
DHW TANK
(J10A, 9 & 10).
Jumper the
input on
J12A terminal 7 & 8 (OR OVR)
.
Also, at this time wire any pump or valve from
the DHW Pump relay contact
(J13 terminals
16, 17, & 18) N/C, C, & N/O respectfully
to
control flow of the heating water into the tank’s
coil.
2.
Enter the
DOMESTIC HOT WATER
MENU
. Go to
BOILER MODE
and enter
OFF/AUTO
.
3.
DHW SETPOINT
The setpoint should reflect the
temperature desired in the heating loop when a tank is
calling for DHW heat.
4.
LOWER BAND
This is not used.
5.
UPPER BAND
This is not used.
6.
PUMP PRIORITY
Setting this value to
YES
will
turn OFF the system pump when the DHW setpoint
override mode is active. Setting this value to
NO
leaves the system pump on. This active period
includes the post purge of the DHW pump/valve.
7.
Select the menu item
POST PURGE.
This is the time
that the DHW pump relay remains energized after the
DHW demand has been satisfied. Once the tank has
reached temperature, the system/local setpoint will be
reloaded and the post purge time will begin.
8.
Select the menu item:
LOCAL PUMP OFF:
When a
DHW heating cycle begins, what to do with the local
pump/valve is determined:
NO
The local pump/valve will remain running during
DHW heating.
YES
The local pump will shut off with a delay
determined by
LOCAL DELAY: seconds.
This
allows the DHW pump/valve to prove before
shutting off the local pump.
Piping of the system will determine which setting
to use.
9.
Select the menu item:
PURGE TO.
After a DHW
cycle completes, the pump/valve can be selected to
either purge to the
TANK
, or to the
SPACE
for the
duration of the post purge time. This selection can use
the space to dump the heat from the boiler and not
overheat the DHW tank/load.
10.
Set the
HYB SENSOR = OFF
. This sensor is
selectable for Method 5A only.
Follow the same steps as used to program DHW Heating
using a Header Sensor INPUT.
USE SENSOR,
select
Yes
.
