Exhaust Vent; Exhaust Port Connections; Figure 3 Exhaust Vents - Thermo Scientific BF51728 Installation And Operational Manual

| Installation
Chapter 4
|
4-20
330985H01

Exhaust Vent

Flow from the exhaust vent on the top of the unit can be adjusted by inserting or removing
the plug provided.
For most applications, the exhaust vent should be fully plugged during operation of the
furnace; a closed vent results in more efficient operation and greater temperature stability.
However, there are some applications which benefit from a partially or fully open exhaust
vent.
The exhaust vent should be partially or fully open for the following applications:
To provide slow cool down of work load. Some work loads may be damaged by heat

shock when the furnace door is opened. The vent can be opened to allow work load
to cool gradually.
To remove unwanted vapors and gases from the furnace chamber. If you need to

ventilate vapors and gases outside of the room, be sure to read section "Exhaust Port
Connections".
"Exhaust Vents" shows how you can use the plug to adjust flow from the exhaust vent.

Figure 3 Exhaust Vents

Exhaust Port Connections

The 1" (2.54 cm) diameter exhaust port through the top wall of the furnace allows for the
removal of unwanted vapors and gases produced during high-temperature operation.
When you need to ventilate vapors and gases outside of the room, be sure to make a
proper connection to the exhaust port that allows some room air to flow into the exhaust.
This is necessary to prevent "chimney effect" which sucks heat out of the chamber and
results in slow run-up time or poor temperature uniformity.
Two methods of making the exhaust port connection are shown in "Preventing Chimney
Effect". With a hood suspended above the furnace, be sure that there is at least
3" (7.62 cm) between the hood and the exhaust port. If you use a metal tube or pipe,
leave at least 1" (2.54 cm) clearance.
1100°C Box Furnace