Camus Hydronics DFH500, Инструкция по установке, эксплуатации и обслуживанию

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PART 5 ELECTRICAL &
CONTROLS
IT IS EXTREMELY IMPORTANT THAT THIS UNIT BE
PROPERLY GROUNDED!
5.1 ELECTRICAL CONECTIONS
Minimum 120VAC 60Hz single phase (15A. circuit) is
supplied to the control junction box models DF-500 through
DF-2000 and 120VAC (20A circuit ) models DF-2500 thru
DF-3000 and 120/230VAC 60Hz single phase (20A circuit)
models DF-3500 through DF-4000 and 120/230 VAC 60Hz
single phase (30A circuit) models DF-4500 through DF-
5000. The combustion air fan motor operates on 230 VAC,
3 ph, 60 Hz. This three phase voltage is generated by the
variable frequency drive (VFD) and supplied directly to the
fan motor. The appliance, when installed, must be
electrically grounded in accordance with the requirements
of the authority having jurisdiction or in the absence of such
requirements, with the latest edition of the National
Electrical Code ANSI/NFPA No. 70. When the unit is
installed in Canada, it must conform to the Canadian
Electrical Code, C22.1, Part 1 and/or local Electrical Codes.
•
All wiring between the appliance and field installed
devices shall be made with wire having minimum
220ºF (105ºC) rating.
•
Line voltage wire exterior to the appliance must be
enclosed in approved conduit or approved metal clad
cable.
•
The pump must run continuously when appliance is
being fired.
•
To avoid serious damage, DO NOT ENERGIZE the
appliance until the system is full of water. Ensure that
all air is removed from the pump housing and piping
before beginning initial operation. Serious damage may
result if the appliance is operated without proper flow.
•
Provide the appliance with proper overload protection.
5.2 VARIABLE FREQUENCY DRIVE (VFD)
This appliance uses a Variable Frequency Drive (VFD)
which provides power to the combustion fan. The fan motor
operates on 230VAC 3 phase power. This three phase
voltage is generated by the VFD and supplied directly to the
fan motor. The VFD receives a modulating signal (4-20 mA
or 2-10 VDC) from the local modulating control or a remote
source based on water temperature to vary the frequency
of the voltage supplied to the fan motor from 20 Hz up to 60
Hz. This varies the output of the combustion air fan from
20% up to 100% of capacity corresponding to the same
variation in burner input. The VFD is driven towards 100%
during the pre-purge portion of the start-up sequence. Once
control self checks are completed, the VFD is provided with
a signal to operate at soft start level for initial burner
ignition. After main burner ignition is established, the
modulating signal provided will use the VFD to vary the fan
speed based VFD to vary the fan speed based on
desired
water temperature set point.
CAUTION
The voltage output from the variable frequency drive to the
combustion air fan is 230VAC, 3 Phase.
AVOID
contact
with high voltage wiring
5.3 DIFFRENTIAL AIR PRESSURE SWITCH
A differential air pressure switch is used to prove operation
of the combustion air fan. The pressure switch sensing
points are installed at the fan outlet as the air moves into
the inlet of the burner. One point measures total pressure
(+air) and is connected to a pitot tube facing the flow from
the fan paddle wheel. The other point measures static
pressure. Differential pressure at the switch will be affected
by blockages at the fan inlet or at the flue discharge. A
minimum differential pressure across the sensing points of
the pressure switch proves operation of the combustion air
fan. This is set in the factory and may be adjusted for field
conditions. The diagnostics display will exhibit a Status of
no Air Flow when the differential pressure switch detects a
sustained low air condition. This condition could be caused
by a number of factors including:
•
Sensing line broken or loose fitting.
•
Dirty filter or blocked vent.
•
Steady high wind condition.
•
Incorrectly set switch.
•
Missing bleed restrictor at differential pressure switch
on static pressure side air line (models DF-4500 & DF-
5000).
5.4 HIGH and LOW GAS PRESSURE
SWITCHS (Optional)
High and low gas pressure switches are available as an
option and are wired in series with the air flow switch. The
high gas pressure switch is used to monitor the differential
gas pressure between the outlet of the control valve and
the fan inlet. If differential gas pressure exceeds the
maximum setting of the pressure switch, the appliance will
shut down and a low air condition will be indicated on the
display panel. The low gas pressure switch is to monitor the
minimum incoming gas supply pressure supplied to the gas
train. If If gas pressure falls below the minimum setting of
the pressure switch, the appliance will shut down and a low
air condition will be displayed on the display panel.
5.5 HIGH LIMIT
A High Limit aqua-stat control is located at the back of the
appliance and the control bulb is installed in a dry well in
the heat exchanger header outlet. The setting of this control
limits maximum discharge water temperature. A manual
reset high limit will have a red reset button which must be
pushed whenever water temperature has exceeded the set
point of the manual reset limit. The temperature of the
water in the heat exchanger must drop a minimum of 15°F
(8.3°C) below the setting of the high limit control before the
reset function can be activated. Whenever an appliance is
supplied with both an auto reset and manual reset high limit
always set the auto reset limit 10
ºF (5.5°C) below the
manual reset limit. This will prevent nuisance tripping of the
manual reset.
5.6 IGNITION CONTROL MODULE
This appliance uses a proven hot surface ignition control
system. The operation of the electronic control module for
the hot surface igniter proves the presence of an ignition