Despatch RFD1-42 -2E with Protocol 3 - Manual (Page 15)

RFD1-42-2E Oven Owner’s Manual T HEORY OF O PERATION
Version 1 15
Copyright © 2012 by Despatch Industries.
All rights reserved. No part of the contents of this manual may be reproduced, copied or transmitted in any form or by any
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retrieval systems without the written permission of Despatch Industries, unless for purchaser's personal use.
Damper slide
Damper Control
Figure 3. RFD1-42-2E Oven Damper Control.
3.2. Damper Control
The RFD1-42-2E oven comes with a manually adjustable damper mechanism which controls the
flow of fresh air into the chamber. The damper control is located on the left side of the oven
(Figure 3). The maximum amount of fresh air is distributed into the chamber when the damper is
in full open position. An additional adjustable damper is provided on the exhaust (Figure 4).
3.2.1. Determining Damper Settings
The optimum setting for the amount of fresh air that
should be
distributed into the chamber depends on several
factors. These factors include ambient environment
temperature, load conditions, load distribution, heat-up
rates, cool-down rates, desired temperature uniformity
and, most importantly, the desired operating temperature.
Carefully consider existing engineering tradeoffs while
using guidelines to determine the fresh air damper setting.
In general, the damper should be set so that the amount of
fresh air flowing into the chamber agrees with the desired
operating temperature conditions. The following
paragraphs show the considerations involved with various
damper position settings.
3.2.1.1. Damper Full Closed Position
The chamber achieves maximum attainable heat-up rates when the fresh air damper lies in the full
closed position. With the damper in the full closed position, the chamber will operate at the
desired temperature using the minimum amount of power. In most cases, the oven also efficiently
operates at the chamber’s maximum operating temperature when in the full closed position.
3.2.1.2. Damper Full Open Position
The chamber operates at its minimum operating temperature with the fresh air damper in full
open position.
Friction heat from the air recirculation system builds up in the chamber. This causes chamber
temperature to rise slightly even without the heating system on. The chamber reaches thermal
equilibrium temperature after the recirculation motor runs for an extended period of time.
Notice
With the damper in full closed position, a predetermined amount of
fresh air enters the chamber via cutaways in the fresh air and exhaust
dampers. This amount of fresh air meets NFPA86 Safety Guidelines for
Class A ovens.