OPTIONAL FEATURES
HeatNet Control V3 3.x
Page 64
Circulator Pump Options
There are provisions for a system pump(s) and a local pump.
This is to allow for primary/secondary loop configurations.
The system circulator pump is implemented using the K4,
K13 RELAY and normally open contacts at J16 SYSTEM
PUMP 1 and SYSTEM PUMP 2.
The pumps require motor contactors to isolate
the on-board relay contacts. The on-board
relays should never be used to energize large
pumps directly.
Figure 46
shows the
connections without contactors for illustrative
purpose.
Figure 46
System Pump connections
The
system circulator pump
is supported by (2) modes and
special features.
1.
The first mode will allow the circulator pump to remain
on, unless the control’s outside high air temperature
setting has been met when using OUTDOOR AIR
RESET.
2.
The second mode will allow the circulator pump to be
turned on whenever there is a call for heat (any control
input). This mode will stop the circulator pump when the
call for heat is lost, and the pump post purge time has
been satisfied.
The summer pump jog is a special feature that can be selected
when the system is in summer shutdown (OUTDOOR
RESET). The jog allows the system circulator pump(s) and
the local pump to run for the system pump purge time once a
week. It can be set to any day of the week and will occur at
12:01 AM. If (2) system pumps are present, and after the first
pump finishes its post purge, the second one will start and the
first one will stop.
The system flow proving switch is implemented using System
Water Flow on J11A, 1 & 2. If a flow switch is connected to
the SYSTEM WTR FLOW interlock, the HeatNet control will
wait up to 10 seconds to prove flow. If flow is interrupted
after it has been established, an error will be displayed, and
the boiler will cycle OFF. If there is a call for heat, every 10
minutes the circulator pump will try to re-establish flow and
start the boiler again.
When (2) system pumps are present, and flow is not
established or is lost (2) things will occur to try and keep heat
in the system.
1.
When first starting a system:
If after a 10 second
wait to establish flow has failed, the first pump will
change to the second pump. The second pump will now
try to establish flow for 10 more seconds. If the second
pump fails to establish flow, the HeatNet control waits
10 minutes
. After the 10 minutes has expired, the
control now starts with the second pump and attempts
to prove flow for 10 more seconds. If flow does not
prove, the control changes to the first pump and
attempts to prove flow. This cycle will continue
indefinitely until flow is established.
If flow is lost
while running:
this process is also used as an attempt
to re-establish flow.
2.
If PUMP ROTATION is set to PUMP HOURS, the
PUMP ROTATION will be temporarily set to
SYSTEM HOURS. This is to prevent re-starting the
failed pump due to its runtime hours. Setting the
PUMP ROTATION to SYSTEM HOURS will allow a
retry of the failed pump after the rotation hours has
expired. Power cycling of the boiler or using the
PUMP ROTATION menu will revert back to PUMP
ROTATION = PMP HRS if this was the original
setting.
System
Pump 1
System
Pump 2
K4
K13
System Flow
Prove Switch