Page 11
Operation and maintenance instructions
Envistar / CRAMO
DSCR111125.01
Air handling with the focus on LCC
SV
EN
DA
FI
NO
Continuous product development may give rise to specification changes without prior notice.
3.4 Electric air heater (code ATEE)
Electric air heater (code ATEE)
The air heater consists of ”naked” electric heating rods. Severe fouling on the
rods will cause them to overheat and this will shorten their useful life. This may
also give off a smell of burned dust and in the worse scenario create a fire ha-
zard. Overheated heating rods can become deformed or loosen from their sus-
pension brackets and heat the air unevenly.
Inspection
Check that the heating rods are properly seated and are not deformed.
Cleaning
Vacuum clean or wipe off surfaces to remove any impurities that may be on them.
Operation
1. Simulate reduced need for heat by temporarily lowering the temperature
setting (setpoint), so that all the electric output steps (contactors) switch out,
i.e., to the OFF position.
2. Then substantially increase the setpoint setting and check that the electric
output steps switch in.
3. Reset the temperature setting.
4. Stop the air handling unit (N.B! Do not switch off the power supply with the
safety switch). All the electric output steps should fall out (=contactors in
the OFF position). The air handling unit stop may be delayed roughly 2 – 5
minutes because the fans in the unit must continue to run to cool away the
heating energy stored in the air heater.
The electric air heater is equipped with double temperature limiters. The one that
resets itself automatically should be set to 70 °C.
The overheat protection device that must be manually reset opens the circuit at
approx. 120 °C and is located on the cover panel on the side of the coil.
Find
out why the air heater has overheated and remedy the fault before you re-
set the overheat protection device.
Keep in mind that the risk of overheating increases as the airflow through the
unit decreases. The air velocity should not be less than 1.5 m/s.
