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3.4- AIRFLOW VERIFICATION
Verify the airflow by taking readings of the following points, while
the elements are in heating mode:
a. Total amperage of all the heating elements;
b. Voltage at the furnace;
c.
Supply air temperature. The point of the reading must not
be affected by radiant heat from the elements;
d. Return air temperature.
From these readings, one can arrive at an approximate
calculation of the average airflow. To do that, the following
formula should be used:
0.82 x amps. x volts
Liter/s= -------------------------
Diff. temperature ˚C
3.1 x amps. x volts
CFM = ------------------------
Diff. temperature ˚F
3.4.1- Supply Air Temperature Rise Test
1. Operate the unit at maximum power for at least 10 minutes;
2. Measure the air temperature in the return air plenum;
3. Measure the air temperature in the largest trunk coming off
the supply air plenum, just outside the range of radiant heat
from the heat exchanger. 0.3 m (12”) from the plenum of
the main take-off is usually sufficient;
4. Calculate the temperature rise by subtracting the return air
temperature from the supply air temperature.
If the temperature rise exceeds the temperature specified in
Table 2 by
5˚F/2.8°C, move the “AC/HP CFM ADJUST” black
wire to high (HI) position. If the excessive temperature rise
cannot be reduced by increasing fan speed, investigate for
ductwork obstructions or dirty and improper air filter.
CAUTION
It is important to check the airflow and to ascertain that the
unit does not operate above the temperatures specified in
the Technical Specifications (Table 2). This is particularly
important if a cooling coil or a heat pump has been installed
in the ducts.
Hi-Limit thermal protectors should never need to engage
during the normal functioning of the appliance. They are
strictly designed to engage during the improper functioning
of the blower or when the filter was improperly maintained.
3.4.2- High limit verification
After operating the furnace for at least 15 minutes, restrict the
return air supply by blocking the filters or the return air register
and allow the furnace to shut off on High Limit. The electric
heaters must deactivate themselves before the warm air
temperature exceeds 200˚F (93°C).
Remove the obstruction and the elements should restart after a
few minutes.
4- MAINTENANCE
WARNING
Electrical shock hazard.
Turn OFF power to the furnace before any disassembly or
servicing.
Failure to do so can result in death, bodily injury and/or
property damage.
Preventive maintenance is the best way to avoid unnecessary
expense and inconvenience. Have your heating system
inspected by a qualified service technician at regular intervals.
Do not attempt to repair the furnace or its controls. Call a
qualified service technician.
Before calling for repair service, check the following points:
1. Check fuses or the circuit breakers;
2. Check if the 15 A circuit breaker on the furnace is
disengaged;
3. Check if the 5 A fuse of the control board is blown;
4. Set the thermostat higher than room temperature. If the unit
does not start up, cut the power and call a qualified service
technician.
When calling for service or ordering a replacement part, specify
the model and serial number of your appliance.
4.1- AIR FILTER
The disposable filter should be replaced twice a year. The
presence of animal hair, dust, etc. may necessitate more
frequent changes. Dirty filters have an adverse effect on the
performance of the central heating system.
4.2- MOTOR LUBRICATION
Do not lubricate the blower motor, since it is permanently
lubricated.
