Sequence Of Operation; Oil Fired Heating Mode; Cooling Mode; Continuous Blower Mode - CAC / BDP CVMAAR036105 Installation Instructions Manual

d. Take a CO sample at the same test location where
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the smoke reading was taken and make note of it;
e. Adjust the burner air setting to obtain a CO
1.5% lower (or a O
reading associated with the "trace" of smoke;
f. This method of adjusting the burner will result in
clean combustion
between 0 and a trace) and ensure the proper
functioning of the system.
4. A barometric draft regulator, supplied with the furnace,
must be installed, in order to ensure proper draft
through the furnace. The barometric damper must be
mounted with the hinge pins in a horizontal position and
the face of the damper vertical for proper functioning,
(see instructions included with damper). After the
furnace has been firing for at least five minutes, the
draft regulator should be set to between -0.025" W.C.
and -0.035" W.C.;
5. The over fire pressure that is taken through the
observation door located in the centre of the front panel
above the burner is a measurement that is necessary to
determine if there is a blockage in the heat exchanger
or the flue pipe. Please refer to the Technical
Specifications in this manual for over fire pressure
values. A high pressure condition may be caused by
excessive combustion air due to the air band being too
wide open or a lack of flue draft (chimney effect) or
some other blockage, such as soot in the secondary
section of the heat exchanger or the use of an oversize
nozzle input or high pressure pump;
6. After all the set up procedures mentioned above have
been completed, the burner should be fired and an
inspection mirror should be used to observe the flame
pattern at the tip of the nozzle. Any irregularities such
as burning to one side or pulsating flame patterns
should be corrected by changing the nozzle.
3.5

SEQUENCE OF OPERATION

Using schematic diagram in Figure 13, follow the sequences
of operation through the different modes.
NOTE: ECM variable speed motors deliver infinitely variable
CFMs. At start-up the motor increases its speed gradually,
in order to lower noise perception. ECM motors ramp down
in the same gradual fashion as they do on start-up. ECMs
are energized by 120V, whenever power is available to the
furnace control. However, they operate only when 24V
motor control signals are received.
3.5.1

Oil fired heating mode

1. The thermostat closes R to W.
2. Burner motor fan pre-purges the combustion chamber
for 10 to 15 seconds, establishing the combustion air
pattern. During this time a spark is also established.
The fan starts at 13% of nominal heating for a period
equivalent to the "Pre-Run Delay". Refer to Tables 8
and 9 ;
3. The solenoid valve opens and a flame is established. A
short time after that, the ignition transformer ceases
sparking.
4. After the "Pre-Run Delay" the blower slightly increases
its speed for a period of time equivalent to the "Short-
Run Delay". Refer to Tables 8 and 9.
reading
2
reading 2.0% higher) than the
2
(Bacharach smoke
5. After the "Short-Run Delay" the blower increases its
speed in order to reach the CFMs indicated in Tables 8
and 9.
6. The call for heat is satisfied.
7. The solenoid valve closes, the burner motor stops and
the flame extinguishes.
scale
8. The blower slows down gradually to 38% of nominal
CFMs for a period of 3 minutes and then stops.
3.5.2

Cooling mode

NOTE: On units using a 2-stage compressor, the terminal
Y1 must be used. Once the Y1 terminal on the electronic
control receives a 24 V signal, the airflow is reduced by 20%
percent. If a single stage compressor is used, do not use the
Y1 terminal.
1. The R - G-and R - Y/Y2 thermostat contacts close. The
R-Y/Y2 circuit starts the outdoor unit, and the R - G
circuit starts the blower at cooling speed. Refer to
Tables 8 and 9.
2. When the call for cooling is satisfied, the R - G and R -
Y/Y2 thermostat contacts open. The cooling unit stops
and furnace blower stops after a period of 3 minutes.
3.5.3

Continuous Blower Mode

1. When the R – G thermostat contacts close, the blower
functions at 64%, 75% or 86% of cooling airflow,
depending on the adjustment of the DIP switches. Refer
to Tables 8 and 9.
2. 2. When the R – G thermostat contacts open, the
blower stops immediately.
3.5.4 Heat Pump – Heating / Cooling Mode
NOTE 1: On units using 2-stage compressors, terminal Y1
must be used. When Y1 on the electronic control board
receives a 24 V signal, the airflow is cut by 20%. If a single
stage compressor is used, do NOT use terminal Y1.
NOTE 2: A dual-fuel thermostat is required when a variable
speed furnace is used with a heat pump. See dual-fuel
thermostat Installation Instructions for interface connections.
The interface prevents simultaneous operation of both the
furnace and heat pump and prevents direct transition from
heat pump to furnace operation.
Cooling Mode
1. The thermostat contacts R - G, R - Y/Y2 and R - O
close. The R - Y/Y2 circuit starts-up the outdoor cooling
unit, the R - O maintains the reversing valve in the
cooling mode and the R - G circuit starts-up the blower
at cooling speed. Refer to Tables 8 and 9.
2. When the call for cooling is satisfied, the R - G, R -
Y/Y2 and R - O contacts open. The cooling unit stops
and the furnace blower stops after for a period of 3
minutes.
Heating Mode Thermo Pump
1. The thermostat contacts R - G and R - Y/Y2 close. The
R - G circuit starts-up the blower at heating speed by
way of the Thermo Pump. Refer to Tables 8 and 9.
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