Dettson FEM10-M2301CM-B, Installation Instructions And Homeowner'S Manual

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7
2.7.1.
Humidifier and electronic air cleaner
This unit is equipped with a 120 VAC terminal for the connection
of accessories up to a maximum of 2 amps. To use this
function, a 3-wire 120/240 VAC power supply is required on the
unit. A humidifier and an electronic air cleaner can be wired to
terminals “1” and “2” of the unit. Refer to the wiring diagrams in
this manual. A field supplied 240/24 VAC transformer can be
installed for accessories using 24 VAC. A separate power
source must be used if the accessories draw more then 2 amps.
Certain accessories require control relays. A location has been
set aside in the unit for the installation of relays: a 24 VAC (part
number L01H009). In addition, a 24 VAC relay can be wired
between terminals “W1” and “C” to be activated during a call for
heat. Refer to the wiring diagrams for the location of the relay
(RAcc) on the control panel.
2.7.2.
Use of a heat pump
When using a heat pump, a kit is required that prevents the
operation of the electric elements and the heat pump at the
same time. Refer to the instructions provided with the
thermostat or the “Fossil Fuel” type kit for the proper wiring of
the furnace and the heat pump.
The simultaneous operation of the electric elements and the
heat pump will cause overheating of either unit. The safety
controls of the appliances will shut down the elements, since
they are not designed to function in this fashion.
3 OPERATION
3.1 START-UP
Before starting up the unit, be sure to check that the following
items are in compliance:
1) The electrical installation and ventilation;
2) The blower access door is in place and the blower rail
locking screws are well tightened;
3) The blower speed adjustments for heating and air
conditioning are appropriate and according to the
specifications in this manual;
4) The thermostat of the room is in the heating mode and
is set higher than the ambient temperature.
To start the unit, turn the main electrical switch on.
3.2 OPERATING SEQUENCE
.
Heating mode
1) The thermostat closes the R-W1 circuit (24 VAC),
thereby activating the first 22 VDC relay passing by a
rectifier control. Without delay, the first heating element
is activated and the blower starts at low speed. On 15
kw unit power and more, a second relay is activated
after a 5 seconds delay to start one or two heating
elements depends on the unit power.
2) The thermostat closes the R-W1 & W2 circuit (24
VAC), thereby activating another 22 VDC relay passing
by a rectifier/timer with a 8 seconds delay (there is 2
relays for the 27 kw unit). The heating elements of the
second stage are activated after the 8 seconds delay.
The 24 VAC relay of the heating speed is also
activated and heating blower speed start.
Cooling mode
1) The thermostat closes the R-G circuit, thereby
activating the 24 VAC R-1 relay. The blower starts up
to cooling speed.
2) The thermostat closes the R-Y contact, thereby
activating the compressor relay of the air conditioner.
Continuous Fan speed
The blower will also start up to cooling speed by way of the
“Fan” switch on the thermostat.
3.3 USE OF MANUAL FURNACE CONTROLS
FIGURE 4
Manual Furnace Controls
When there is a demand for heat, the pilot light (“L-1”) comes
on. Refer to the wiring diagram.
When the ”HI/LO” switch is put into the “LO” position, it will shut
down approximately half the elements.
However, it is important to put the switch back to the “HI”
position during the winter months to ensure adequate
heating.
Also, this switch must remain in the “HI” position when a 2-stage
or outdoor thermostat is used to control the electric elements of
the second stage. Refer to the diagram in Section 1.5) above
(Typical 24 VAC Wiring, Thermostat).
The “ON/OFF VENT/FAN” switch engages the blower in the
continuous low speed mode. This will filter the air and provide
for better air distribution in the building.
The circuit breaker is there to protect the motor and control
circuit conductors. If the unit does not function, press the circuit
breaker button to see if it may have disengaged due to a power
surge. If the breaker has to be pressed again, the unit must be
checked by a qualified service technician.