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6.6.2. CONNECTING THE ELECTRICAL HEATER
• Use the electric heater to heat clean air. Fire risk is increased when the electric heater
gets dirty, therefore it is recommended to place an air filter before the heating element.
• The electrical installer must provide airflow control device, so that, the electrical heater
operates when the minimum airflow is reached, or when the air speed over the heater is
more than 1.5 m/s.
• The electric heater should operate if the fan is off. The fan should stop only after discon-
necting the strength and entire cooling, or at the same time as the fan is activated.
• The fan must stay off after the stop and cooling of the coil.
• Do not touch the heater when it is working.
• In case that one of the control devices was activated, switch off the unit and verify the
installation before restarting.
• In UTBS equipment with electric heater elements incorporated, there is a possibility of
high temperatures inside the unit.
• In units without factory integrated controls, the connection of electric heater batteries,
as well as the satisfactory protection of the electrical circuit (stop/ start) will be the res-
ponsibility of the installer.
• The electrical installation must be carried out by qualified personnel.
• All electrical installation should be performed as indicated in the following points:
A) Perform the wiring of the thermal protector to safety contactor of electric heater
batteries.
B) Install a flow detector that is interlocked to the safety contactor of electric hea-
ter batteries, to prevent the operation in the absence of airflow over the heater
elements.
C) Incorporate an overrun timing circuit so that after the equipment is switched
off the fan continues to run to cool the elements and prevent ‘hot spot’ damage:
Step 1 : Stop power to the heater elements.
Step 2 : Fan continues to run for minimum overrun time (2 minutes).
Step 3 : Stop the fan.
