Milnor 5050, Руководство по обслуживанию

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Pellerin Milnor Corporation
2. About the Min Fire and Outlet Temperature Exceeded 220°
Faults
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The function of these faults is to prevent conditions that can cause a fire. The controller does the
necessary steps. There are no other steps for the operator to do immediately. But the controller
puts data about the fault in the record of dry cycle details. These faults usually cause unsatisfac-
tory operation. To prevent these faults, it can be necessary to change some procedures as told in
the subsequent sections. Heat system adjustments and repairs are not routine maintenance. Speak
to your dealer or Milnor®.
2.1. Min Fire (MINF)
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This condition applies to dryers that use gas or propane. Minimum fire is when the controller tells
the modulating gas valve to go to the position 000. The correct condition is when the gas valve is
open a small, stable increment. Under this condition, a
min fire fault occurs if the controller
senses that the outlet temperature increases. This fault usually shows that the goods became too
hot and could catch fire. (One more symptom is if the goods have a burned smell.) When this
fault occurs, the controller immediately goes to the subsequent cool down step. Some causes of
min fire faults include:
•
The goods are held against the basket
—The correct condition is that the goods tumble in
the basket. If the basket speed is too high, centrifugal force can hold the goods against the
basket. Then the part of the goods that is against the basket can become too hot.
• The gas valve does not operate correctly —For example, the valve throttle cannot move
down fully because it is damaged. This can prevent the min fire position.
•
Min fire is set too high
—The min fire position must be adjusted correctly when the gas and
air as told in the procedure to set the heat system. Damage to components can cause this ad-
justment to change.
2.2. Outlet Temperature Exceeded 220° (degrees Fahrenheit)
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This fault applies to all dryers except those with steam valves that do not modulate. The value
220° F (104° C) is 5°F (3° C) below the temperature that will close the outlet temperature
switches (Fenwal switches) and start water flow. It cancels each subsequent heat step if the outlet
temperature is higher than 220° F (104° C) for five seconds or more at the start of the step. This
fault can also occur if the goods are held against the cylinder or the gas valve is damaged. The
function of this fault is to make water flow not necessary, if the goods are not on fire. But if the
goods catch fire, the temperature switches will quickly close to start water flow.
3. How to Prevent Water Flow When No Fire Occurs
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If water flow occurs when there is no fire, two possible causes are:
• A temperature switch is damaged. This is the usual cause. For example, material can hit a
temperature probe and bend it. This can be a piece of goods that goes through a space where
Fire Safety System Operation and Maintenance
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