Troxler ICO 4740, Manual Of Operation And Instruction, Page: 49 / 171

ICO 3-15
INSTALLATION WITHOUT AN
EXHAUST HOOD
NOTE
The ideal configuration utilizes an exhaust hood,
which eliminates the effects of positive or negative air
pressure in the environment. However, the ICO is
tolerant and should perform well in most situations.
POSTIVE AND NEGATIVE AIR PRESSURE
Positive Air Pressure
Many air handling systems pump air from the outdoors into a
building, which creates positive air pressure. If the unit is
vented via a wall exhaust pipe, this positive air pressure will
move air through the furnace and out the pipe, causing the unit
warm-up time and the recovery time after opening the door to
increase. If the airflow is excessive, the unit may not heat up to
the proper temperature (i.e., 540°C +/- 5°C) at all.
Negative Air Pressure
A lot of labs have mounted exhaust fans to move air out of the
area, which create negative air pressure. This causes air to enter
the furnace via the exhaust pipe. If this airflow is excessive, it
will pull exhaust gases into the room.
The best way to mitigate this issue is to configure the airflow lift
with the fans off. (For information about measuring the airflow
lift, see page 3-19.)
1. After the unit is set up, turn off the fans, close the door,
and allow the airflow lift to stabilize. (The ideal range is
between -2.5 and -3.5 grams.)