AEC WD 350 through WD3000 Dehumidifying Dryers - Manual (Page 41)

350-2100 cfm Dryers Chapter 6: Maintenance 40 of 58
Figure 6: Desiccant Amounts Required
Dryer Desiccant Required per Tower
Model Large Bead Small Bead Total
350 30 76 106
350-RT 30 76 106
425 30
90 120
425-RT 30 90 120
500 40
100 140
500-RT 40 100 140
600 40 120 160
600-RT 40 120 160
700 40 35 175
700-RT 40 35 175
850
120 120 240
850-RT 120 120 240
1000
120 130 250
1000-RT 120 130 250
1250
120 180 300
250-RT 120 180 300
1500
120 240 360
1500-RT 120 240 360
1800
120 310 430
1800-RT 120 310 430
2100
120 360 480
2100-RT 120 360 480
6-9 Process Heater Replacement Procedure
ACS dryers have a number of single phase Calrod-type heater elements wired in a delta formation.
They are mounted in the vertical compartment behind the right hand desiccant tower. The number and
wattage of the heaters varies with model, voltage, temperature range, etc., but the replacement
procedure is the same.
WARNING! Disconnect and lock out power before heater replacement.
1. Remove the bolts securing the process heater access cover.
2. Sketch the heater wiring configuration so the heaters may be re-wired properly. Heaters are
mounted on a common plate of three or six for easy maintenance.
3. Remove the jumper bars and wires for the heater plate assembly(ies) being removed or replaced.
4. Remove the bolts securing the heater plate assembly and slide out the assembly. Avoid damaging
the gasketing.
5. Remove individual heaters for replacement by removing the large brass nuts and washers.
6. Re-install the heaters and heater plate assemblies in reverse order, replacing gaskets if necessary.
Caution! Heater loops should not touch each other. "Hot spots" will lead to premature heater
failure.
7. Re-install the jumper wires and bars according to the sketch made earlier.
8. Re-secure the process heater access cover.