Despatch S Type User Manual
Page 35
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I-235 (9/03)
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32
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AIRFLOW TROUBLE SHOOTER
Conditions
Actions
BATCH OVENS
A. Non-uniform work chamber
1.
Check to get a slightly positive chamber pressure by
closing down exhaust or opening up fresh air. See
damper instructions, also.
2.
Adjust supply louvers—open for cold spots—close for
hot spots. If necessary, adjust return louvers in the
same manner.
B. Cold by door
1.
See A-1.
2.
Check door seals.
3.
Open supply louvers close to door.
C. Positive pressure in chamber
1.
Close fresh air damper.
2.
Open exhaust damper.
3.
Check joining connection on return air into heater box
(check with smoke around outside of heater box). If
leaky, fit joint and then reseal.
D. Negative pressure in chamber
1.
Close exhaust damper.
2.
Open fresh air damper.
3.
Open supply louvers slightly.
CONTINUOUS OVENS
E. Cold on ends
1.
Close down the exhaust damper.
2.
Open fresh air damper.
F.
Heat blowing out on ends
1.
Close fresh air damper.
2.
Open exhaust damper.
3.
See C-3.
4.
Adjust supply louvers by end opening.
5.
Make sure cold air is not being pulled in at the bottom
of the end opening—adjust louver if necessary.
ALL OVENS
G. Will not reach operating temperature
1.
Close exhaust damper.
2.
Close fresh air damper.
3.
Quite often the cause is the burner not up to capacity
because of gas pressure or burner adjustment. If
problem persists after assurance has been made that
the unit BTUH OUTPUT is the same as on the rating
plate, proceed to Number 4.
4.
See C-3.
5.
Check the supply duct joint between the heater box
and the oven. If leaky, fix joint and then seal.
WARNING
Too much positive pressure in an oven creates a high outer skin temperature because hot air is forced out
through panel joints and around door seal and could possibly warp the front.