HeatNet Smith Series, Руководство пользователя

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TROUBLESHOOTING HeatNet Control REV 1.38-1
Page 63
while updating. Restore them for proper communication
with a building management system.
2. Ensure that the USB driver for your PC/Laptop computer
is properly installed.
3. Disconnect BMS or Protocessor Module if connected.
Situation:
All HeatNet Boilers fire at the same time.
1. This is usually caused by the HeatNet addresses on the
Member boilers not being set. If the address on each
boiler is not set, then all boilers will have address = 2 by
default. When the Master boiler calls to fire boiler #2, all
boilers with address #2 will fire. Set each Member boiler
to a unique address from 2-16.
2. Check the ADD Boiler delay time to ensure it is at a
reasonable value. A setting of 0 will start all the boilers
at the same time.
Situation:
The boiler is showing that it is running at 45% and
there is no fire in the sight glass.
1. The Boiler always shows it’s called for firing modulation
%. This is not an indication of what the boiler is actually
firing at. If the ignition control fails to receive a call to
fire (last interlock closed on terminal 6 of the ignition
control) the display will indicate the called for %. Check
if the ignition control is in standby, if so then the HeatNet
control has closed the Start contact on J5..10 (Limits) and
is waiting for the Blower relay to close on the ignition
control which is monitored on J5.3 of the HeatNet control.
Situation:
I can hear the blower ramping up and down and the
firing rate is changing, but the display indicates it is
running at the same modulation rate.
1. The Boiler always shows it’s called for firing modulation
%. This is not an indication of what the boiler is actually
firing at. In this case, the boiler is trying to meet the called
for modulation % which is displayed, but is unable to do
so. The boiler protects itself by looking at it’s supply
water temperature and the temperature is probably in the
Operating Limit Band. While in the operating limit band,
the HeatNet control limits the input of the boiler. The
boiler tries to deliver the most input it can in an attempt to
meet the called for modulation % without tripping the
operating limit.
2. If the boiler is constantly varying in blower speed and in
the operating limit band there may be not enough flow
through the boiler or the Operating Limit/Operating Limit
Band may be improperly set. The Operating
Limit/Operating Limit Band should not overlap the
heating band. This may occur when a building
management system is controlling the setpoint and is
setting the setpoint in the operating limit band.
3. Example: Setpoint set to 180F (by Building Management)
and the Operating Limit is set to 200F with a 20F
Operating Limit Band. When the boiler is trying to deliver
180F to the load it’s supply temperature would be a
minimum of 180F. The beginning of the Operating Limit
Band (looks at supply temp) would be 200F-20F = 180F.
Now, when the Master is trying to maintain setpoint at
180F, the boiler is trying to reduce input beginning at
180F at its supply sensor and as a result, fighting the
setpoint. The Operating Limit band needs to be reduced in
this case, while taking into account the Heat Band
differential.
Situation:
The Master boiler sees all of the Member boilers in
the system, but does not fire any of the Members.
1. If the Master modulates to 100% without firing a Member
boiler and the Member boilers are seen by the Master (in
menu SETUP:BOILERS), then the Member boilers are
sending back offline status to the Master.
a. The Member boilers may have an alarm or error
condition which would be indicated by a blinking
boiler # in the Boilers Firing screen.
b. Ensure the HeatNet is set up properly: Amber lights
blink on HeatNet Jacks. Only one Master boiler.
c. If the Member boiler is in Local Mode then it also
would not be called and report unavailable to the
Master.
d. If the Local flow switch for the Local pump is wired
to the System flow switch input this would also
create an offline condition. The Member needs to
detect system flow or have a jumper across that
sensor input in order for the Member boiler to report
available status. The Local flow prove switch must be
wired to the Water Flow interlock sensor input.
Situation:
We are trying to use a 0-10VDC control signal, but
when we send it 10 VDC only 7 VDC is measured at
terminal
J10B 6 & 7.
1. The HeatNet control was designed to use a 4-20mA
control input. If a 0-10 VDC control signal is to be
used, it must supply at least 20mA. 0-10 VDC control
signals are not recommended due to line loss and the
ability of the control signal to reject noise. So, if