AAF International Type N RotoClone - Manual (Page 12)

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f. Plugged eliminator plates or accumulations in impellers or dirty
air chamber.
g. Plugged air equalizing hose or air leak in hose.
2. Reduced dust collection efficiency can be caused by:
a. Extreme reduction in air flow indicated in Item B-1, above.
b. Corrosion or abrasion to impeller sections.
c. Low water level in RotoClone. Can be observed through closed
portlight. Water level below running level weir can be caused by:
1) Open or leaky drain valve.
2) Insufficient water supply due to plugged strainer in makeup
water line. Prolonged periods of low water pressure can
reduce water supply rate below water evaporation rate in
RotoClone. Evaporation will be greatest on hot, dry days.
3) Incorrect flow control valve. Contact AAF representative
for replacement.
4) Solenoid valve sticking in closed position.
5) Accumulation on electrode in Model “SV” with low water
safety control or Model “A”.
6) The unit out of level. (See Item B-1, Installation Instructions).
3. Water entrainment in Exhauster Discharge:
a. Rain or snow draining into exhauster housing during erection or
shut down.
b. Incorrect position of water eliminator plates in Design 2 or 3.
c. Excessive air flow through RotoClone. Overrating can be
checked by measuring the pressure drop across the RotoClone.
This can be done by subtracting the static pressure directly
upstream of the inlet of the RotoClone from the static pressure
directly downstream of the exhaust plenum (between the
RotoClone and the exhauster on draw-thru systems). If the
pressure drop of the RotoClone exceeds the maximum allowable
for the particular operating line the RotoClone was sized for (see
Item 5, Back Page for operating line selected for this unit), this
usually indicates excessive air flow. The maximum allowable
pressure drop for each operating line can be determined from
the operating line chart in Figure 8. The maximum allowable
pressure drop for a particular operating line occurs at its
intersection with the “maximum pressure drop” line.
To stop entrainment caused by excessive air flow, increase static
pressure or reduce exhauster speed.
d. A plugged air equalizing hose will cause the water level control
box to maintain a too-high water level in the unit. Clean the hose
and readjust the water level (See Item A2, Operating
Instructions).
e. Surging of the RotoClone is a rocking of the water from end to
end in the unit. This can be caused by running the unit well
below its rated capacity. Contact the local AAF sales
representative for assistance.
1) Surging can also be caused by a duct elbow at the RotoClone
inlet. Four to five duct diameters length of straight run will
give an even air flow at the inlet. If an elbow is required due to
space limitations, turning vanes in the elbow will evenly
distribute the air and eliminate surging.
f. If the unit is out of level water entrainment will result. (See Item
B-1, Installation Instructions).