Part 5 Electrical & Controls; Electrical Conections; Variable Frequency Drive (Vfd); Diffrential Air Pressure Switch - Camus Hydronics DynaFlame DFW501 Installation, Operation And Service Manual

PART 5 ELECTRICAL &
CONTROLS
IT IS EXTREMELY IMPORTANT THAT THIS UNIT BE
PROPERLY GROUNDED!
5.1

ELECTRICAL CONECTIONS

Table 10: Minimum Voltage Requirements
Voltage
Model
Requirement
500 -
120VAC, 60Hz
1200
1500 -
120VAC, 60Hz
2000
2500 -
120VAC, 60Hz
3000
115/230VAC,
3500-
60Hz, Single
4000
Phase
115/230VAC,
4500 -
60Hz, Single
5000
Phase
115/230VAC,
4504-
60Hz, Single
5004
Phase
230VAC, 60Hz,
6004
3 Phase
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.
Maximum
Over Current Full Load
Protection Amps
[Amperes] [Amperes]
15 7
20 11
20 14
20 16
30 24
30 24
30 17.8
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 normally open 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, and DF-6004).
5.4

BLOCKED FLUE SWITCH

A normally closed block flue switch is used to shut down
the appliance under the following conditions:
1) Air intake 50% blocked
2) Vent outlet 80% blocked
22