CONTROL METHODS
HeatNet Control V3
Page 32
used to determine when boilers are started along with
the ADD BOILER DELAY TIME.
4.
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 SETPOINT
+ UPPER BAND). Setting the SHED BOILER
DELAY TIME = 0 will shut off all boilers
immediately once the (DHW SE UPPER
BAND) is exceeded.
5.
Now, determine if the DHW priority is required by
the 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.
6.
Select the amount of time for the
POST PURGE
of
the DHW pump. 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.
B.
Pump on the Master boiler functions as a global
pump.
7.
Now, in order to be a Master boiler, it must have a
Header sensor. In method 1 DHW Only, we will
employ the DHW sensor (J10-A, 9 & 10) in this
system instead of a Header sensor?
USE SENSOR
in
this example will be set to
YES.
This will allow the
boiler to control the DHW tank or system loop
temperature as a Master boiler using the DHW sensor.
The upper and lower differential temperatures will
also be loaded.
8.
The
SHARING
item is set to
OFF,
only boilers that
are not firing will be checked for runtimes and fired.
9.
Set the
LOCAL PUMP OFF
value to
NO.
This
will
leave the local pump on during a DHW heating cycle
(backwards compatibility). Setting this value to YES
will always keep the local pump off.
The Master’s DHW relay will remain on as long as
there are boiler’s firing and the DHW temperature
is below the (DHW SE UPPER BAND).
Once all boilers are off and the DHW temp is equal
to or above the (DHW SE UPPER
BAND), the DHW pump will begin its post-purge
time. If during this post-purge time the DHW temp
falls below the (DHW SE UPPER
BAND), the DHW pump will remain on.
Setting this value to
YES,
will shut the local pump
off during a DHW heating cycle, but will keep the
local pump on for the LOCAL DELAY: 10s time
before shutting off. This LOCAL DELAY: time
can be adjusted in the next menu item by pressing
the down arrow again.
10.
Press the DOWN arrow again and the menu item
:
will be displayed.
Set the
PURGE TO
value to
TANK.
This will
purge the heat from the boiler into the tank or
system loop. This will be done using the DHW
pump after the DHW heating cycle is complete.
If the
PURGE TO
: is set to
SPACE
, once the
DHW cycle has completed, the Master will shut the
DHW pump off within a few seconds. The
SPACE
setting should only be used only for combination
space and DHW heating.
Now in the,
SETTINGS: DISTRIBUTED CONTROL:
MASTER TYPE
select
DHW
.
NOTE:
JPS1 MUST be cut on all DHW boilers.
