AirTek TW15 Installation, Operation & Maintenance Manual - Page 8

Browse online or download pdf Installation, Operation & Maintenance Manual for Dehumidifier AirTek TW15. AirTek TW15 20 pages. Heatless desiccant compressed air dryer

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Models TW10 & 15 are provided with a needle valve for

purge adjustment. A purge indicator for this low a flow is

not practical. The purge flow should be set to feel. As a

minimum it must be set high enough so that the dryer

achieves full repressurization prior to switching. If perfor-

mance is unacceptable, increase purge flow. Purge flow

can be determined if there is a system flow meter in place,

via addition or subtraction from the flow meter.

Models TW25, 40 & 55 are provided with a needle valve for

adjustment and an orifice and pressure gauge for metering

and indication. Adjust the needle valve so that the purge

(center) pressure gauge reads the correct purge pressure as

determined above. The setting may vary slightly with line

pressure.

Some special models are equipped with flow meters that

read purge directly in SCFM. Adjust the needle valve so

that the flow meter reads the correct purge flow..

C. DRYER OUTLET FLOW:

Dryer outlet flow is equal to the dryer inlet flow minus the

purge flow.

A. DRYERS EQUIPPED WITH POWERLOC:

The PowerLoc is a Digital Dewpoint Monitor and Demand

Cycle Controller. The sensor is a thin film gold aluminum

oxide design. The PowerLoc monitors the outlet pressure

dewpoint of the dryer and digitally displays it.

The Demand Cycle Control feature tailors the dryer cycle to

actual loading conditions, maximizing energy usage.

Without the PowerLoc the cycle is fixed and "worst case"

design conditions are assumed.

The Demand Cycle is accomplished by providing a discrete

dry contact closure across the CycleLoc terminals on the

Sequence Annunciator. The Variable Cycle Switch must be

set to the 100% load setting and JP1 must be removed for

the PowerLoc to work!

If the dryer is maintaining a good dewpoint AFTER the first

five minutes of drying, the PowerLoc will override the fixed

cycle and keep the current tower on-line until it is saturated

to design loading (switchpoint valve), usually –40º. If this

occurs the offline bed, which has just finished being

regenerated, will repressurize and be ready to go on-line.

The CycleLoc light on the Sequence Annunciator and the

PowerLoc Mode light on the PowerLoc will be on at this

time. Once the dewpoint degrades to the switchpoint valve,

the freshly regenerated bed will go on-line, and the satu-

rated bed will depressurize and begin regeneration.

Note that the PowerLoc cannot shorten the cycle. The

drying tower will always be on-line a minimum of five

minutes and the regenerating tower will always undergo a

design regeneration cycle of 4 minutes and 15 seconds.

Thus the PowerLoc can only compensate for "under"

loading, not overloading conditions.

AIRTEK

4087 WALDEN AVENUE, LANCASTER, NY 14086

If there is any error with the PowerLoc, the dryer will default

to the fixed time cycle. There is also a PowerLoc On/Off

switch located in the control enclosure. If this switch is

turned off the dryer will operate in the fixed time cycle. The

PowerLoc will continue to display dewpoint.

The PowerLoc is fully programmed and wired at the

factory if ordered with the dryer. All that is normally

required is sensor installation. The sensor should be

installed (without cable attached) only after the dryer has

cycled 3 or more times and the sample line has been "blown

out". Do not allow the probe to bottom out in the sample

line. Do not tighten ferrule on sensing tip. Hand-tighten

nut, wrench tighten 1-1/2 turns. Open the probe isolation

valve slowly to full open position. This allows operation at

full line pressure for correct reading of pressure dewpoint. A

coil of capillary tubing is provided to allow a small sample

flow over the sensor and prevent ambient moisture from

infiltrating the system. Check the bleed periodically to

ensure it is not clogged.

Following sensor installation allow the sensor to stabilize at

line pressure for four hours prior to attaching the sensor

cable.

Failure to follow the above precautions may result in sensor

failure not covered by warranty.

Upon installation the sensor may be saturated. Even if the

dryer is producing a good dewpoint, it will not be indicated

immediately as it will take a period of time for the sensor to

dry out and come to equilibrium with the system. The

sensor will also become saturated if the air system is shut

down and allowed to depressurize. Upon restart of the

system, the dewpoint may appear to be poor, even though

the dryer may be producing clean, dry, air.

Although the probe can be exposed to occasional, brief

periods of liquid saturation, it can not be exposed to

continuous wet conditions. If your dryer is overloaded and

saturated, or if it will be shut down for an extended period of

time; remove or isolate the probe until the problem is

resolved.

Refer to the separate PowerLoc Manual for additional

information.

10. A. MAINTENANCE PROGRAM:

DAILY:

Check dewpoint or humidity level, if instrumentation is

available. Any difficulty with the dryer will result in poor

dewpoint performance.

Check for correct purge setting and air flow from purge

exhaust.

Check gauge readings & sequence of operation

through complete cycle.

Check auto drain operation on Prefilter, Separator &

Receiver. A manual drain valve installed (in addition to

the automatic drain at these points will ease checking

of the automatic drains.

Ensure there is no backpressure in the regenerating

tower (Pressure = 0 PSIG).

Tel: (716) 685-4040

Pg. -8-

Fax: (716) 685-1010