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HEAT & MASS TRANSFER PRODUCTS

DH 250 Desiccant Dehumidifier

TECHNICAL MANUAL OPERATING & MAINTENANCE

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NovelAire Technologies

DH 250 Desiccant Dehumidifier Technical Manual

Table of Contents 1.0 Description………………………………………………………………………….3

1.1 Principle of Design…………………………………………………………3

1.2 Design…………………………………………………………………….…4

1.3 Design Options……………………….…………………………………….5

2.0 Installation…………………………………………………………………………..6

2.1 Examples……………………………………………………………………6

3.0 Operation and Control…………………………………………………………..…7

3.1 Control………………………………………………………………….……7

3.2 Operation……………………………………………………………………7

3.2.1 Electrical Connections………………………………………….7

3.2.2 First Time Startup……………………………………………….8

3.2.3 Normal Operation………………………………………….……9

3.2.4 Maintenance……………………………………………….…….9

3.3 Troubleshooting……………..…………………………………………….10

3.4 Technical Support and Service……………………………………….…12

4.0 Technical Information…………………………………………………………….12

4.1 Physical Data……………………………………………………………...12

4.2 Unit Information……………………………………...……………………13

4.3 Capacity Diagram……………………………………………………..….13

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1.0 DESCRIPTION

The NovelAire DH 250 Desiccant Dehumidifier is used in a wide range of applications:

− Dehumidifying storage rooms, vaults, small manufacturing, and industrial processing centers

− Extensively used in restoration and water damage applications. − Used in military storage applications, this unit produces dry air in the

storage space to increase readiness, prevent corrosion, reduce maintenance and improve Mean Time Between Failure (MTBF) for electronic systems.

With a process air flow of 150 SCFM and a dehumidification capacity of up to 6-8 pounds per hour moisture removal with regards to inlet conditions. This unit is suited to a broad range of other industrial applications as well. The major components of this dehumidification package are the proprietary NovelAire dehumidification wheel, electric resistance (PTC type) heaters for regeneration, and two blowers (for the process and regeneration air streams). Other elements include a small drive motor to rotate the wheel through the two air streams, and a control panel.

1.1 PRINCIPLE OF OPERATION

The operation of a desiccant dehumidification system is driven by two counter current air streams flowing through the wheel. Return Air from the conditioned space is drawn through the desiccant wheel by the Process Blower. The desiccant adsorbs moisture from the air stream and the blower returns the dry Supply Air to the conditioned space. The moisture containing portion of the wheel is rotated into a separate air stream to be regenerated. Fresh air for the Regeneration Air stream is drawn into the unit through an electric resistance heater. The heated air is then drawn through the wheel before being discharged outside of the conditioned space by the Exhaust Blower. The desiccant releases the adsorbed moisture into the heated Regeneration Air stream, leaving a reactivated desiccant to be rotated back into the Return Air stream. Wheel rotation is continuous between the two air streams, alternately adsorbing moisture from the conditioned space and desorbing moisture into the exhaust stream to be carried outside of the conditioned space.

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1.2 DESIGN

The housing of the DH 250 and all of the components used in the design are of solid construction and selected to withstand rugged use in a wide variety of applications. The interior of the DH 250 is laid out to minimize pressure drop through the wheel and to reduce the overall unit size. The desiccant wheel is housed within a cassette and tightly sealed to separate the process and regeneration sections. A small gear motor is used to drive the wheel at a speed of 24 rph. 24 v control is used to energize the unit. The unit measures 37” long x 15” high x 15” wide and weighs 95lbs. Process supply duct: 6” Regeneration exhaust duct: 4”

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1.3 DESIGN OPTIONS

The unit is factory wired for 220v service. For portability, an optional set of handles and wheels are installed to facilitate easily moving the unit. The unit can use a remote humidistat connected to the dehumidifier with a hard wire which is terminated with a low voltage (24VAC/VDC) plug. This wire is connected to the dehumidifier through a low voltage jack installed in the outside wall of the unit at the location where the Control Dial normally is mounted. A duct transition piece is available to duct the regeneration air into the unit from outside the room.

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2.0 INSTALLATION

The DH 250 Desiccant Dehumidifier is designed to be a free-standing, stand-alone unit. While the DH 250 is normally installed to operate inside the space to be conditioned, with proper ducting, the unit can also be installed to operate outside the space. Whatever installation location is selected, it is recommended that the DH 250 be installed so that the front control panel and the power connection are easily accessible. IMPORTANT - In any installation, the wheel is designed to operate in the vertical orientation. IMPORTANT – To achieve proper operation of the dehumidifier, the Supply Air must always be connected to discharge inside the conditioned space, and the Exhaust Air must always be connected to discharge outside the conditioned space. IMPORTANT – For proper operation of the DH 250, it is necessary that the air flow into and out of the unit be unimpeded. For optimum operation, it is recommended that there be 12 inches clear in front of both the inlet and outlet air streams of the DH 250. 2.1 EXAMPLES

Shown are several examples of the DH 250 as it might be installed for different applications. Note that the Exhaust is outside the Conditioned Space in each example and the Supply Air always discharges inside the Conditioned Space. Best performance will be obtained using the Recommended Installation. Care should be exercised with optional installations. Call manufacturer for information about installation options.

CONDITIONED SPACE

Return Exhaust

Regen Supply

250

CONDITIONED SPACE

Return Exhaust

Regen Supply

250

CONDITIONED SPACE

Return Exhaust

Regen Supply

250

Recommended Installation

Option 1 – Possible infiltration

Recommended Installation

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3.0 OPERATION AND CONTROL

The power switch (or Selector Switch) for the DH 250 is located on the end panel of the unit above the power cord. Once the dehumidifier is connected to the proper power source, it is ready to run. Remember to check that air streams are properly ducted and the air flow through the unit is unimpeded. The DH 250 can be run either in an on/off manual mode or can be controlled by a remote humidistat. The humidistat on/off contact is connected to the unit through a terminal block located below the on/off switch. 3.1 CONTROL

For automatic control a humidistat is connected directly to the DH 250 through the terminal block. This places the humidistat in the 24 VAC control circuit of the unit. The unit will run when the contact of the humidistat closes. For manual operation of the DH 250, place the selector switch in the “Manual” position. The unit will run continuously, dehumidifying to the maximum capacity based on the conditions of the inlet air. Refer to the attached wiring diagrams for further information. 3.2 OPERATION

3.2.1 ELECTRICAL CONNECTIONS 1) When installed, the appliance must be electrically grounded in accordance with local codes or in absence of local codes with the National Electrical Code, ANSI/NFPA 70. 2) The unit is designed to have 220V 60Hz power connected to the terminal block in the control panel in the unit. (See picture at right. Black/red are hot and green is ground.) Ground wire is tied into the ground lug. 220 VAC is connected to black and red at the terminal block.

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3. The controls for the unit are connected on the terminal block on the end of the unit. The diagram below shows a typical humidistat connection. Blue is 24 VAC common, Red is 24 VAC, and Yellow is the unit run signal input (24 VAC). Fuses and circuit breakers are also on the end.

3.2.2 First Time Start Up of the DH 250

1. Be sure that there are no obstructions to the free flow of air into or out of the unit.

2. Set the Selector Switch to “OFF” and plug the DH 250 into an appropriate electrical outlet.

3. Turn the Selector Switch to “ON” and confirm rotation of the desiccant wheel visually by removing the Inlet Filter on the end of the unit and looking through the grill of the Return Air inlet. Replace the Inlet Filter.

4. Confirm operation of the Process Blower by feeling air flow at the Supply Air Outlet on the end of the unit near the power cord. Confirm operation of the Regen Blower by feeling air flow at the Exhaust Air Outlet at the opposite end of the unit.

5. The unit is now ready for routine operation.

Auto/Manual Switch

1) Blue 2) Red 3) Yellow

Fuses

Motor Circuit Breakers

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3.2.3 Normal Operation of the DH 250

1. For continuous, manual operation – Set the Selector Switch to “Manual.” 2. For automatic operation with humidistat control – Connect humidistat into

the terminal block and set humidistat at desired %RH. Set the Selector Switch to “Automatic”.

3. To turn unit off – Disconnect power when in “Manual” or set the humidistat at the highest set point when in “Automatic”.

3.2.4 Maintenance

The only routine maintenance required for the DH 250 is the cleaning and/or replacement of the inlet air filter pads.

Return Air Inlet Clean every 3 months Replace every 12 months

Regen Air Inlet Clean every 3 months Replace every 12 months

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3.3 TROUBLESHOOTING

PROBLEM CAUSE SOLUTIONS

Entire unit is not running Unit running, but not dehumidifying

Unit is in “Automatic” and the humidistat control has turned unit off. No power to unit Heater not operating One or more fans not operating Wheel not rotating Air flow blocked

Check operation of unit by switching to “Manual“. If unit comes on, check operation of humidistat. If unit doesn’t come on, check fuses. If fuses are okay, check for 24 VAC at YEL/ORG terminal block and contactor coil in control panel. (Refer to wiring diagram) Check main power supply. Check fuses on front panel. Replace if necessary. Check for warm air at Exhaust Air Outlet; if not warm, consult factory. Confirm high volume air flow from both Supply and Exhaust Air Outlets. See 3.2.1.4 on previous page. If low flow or unbalanced flow, consult factory. Confirm rotation of wheel. See 3.2.1.3 on previous page. If wheel not rotating, consult factory. Check that all air inlets and outlets are not blocked and allow unobstructed air flows to and from unit. Check and clean both air inlet filters as required.

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Exhaust Air Duct leaking or improperly returning moist exhaust to conditioned space.

Check that all Exhaust Air is ducted outside of the conditioned space.

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3.4 TECHNICAL SUPPORT AND SERVICE

Factory NovelAire Technologies Address: 10132 Mammoth Drive Baton Rouge, LA 70814-4420 Telephone: (225) 924-0427 (800) 762-1320 Fax No.: (225) 934-0340 E-mail: novelair@novelaire.com 4.0 TECHNICAL INFORMATION

4.1 PHYSICAL DATA

Size: L 37” x W 15” x H 15” Weight: 95 lb.

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4.2 Unit Specifications

220v, 1ph, 60 Hz 2.8 KW FLA 13.6 Weight: 95 lbs Process volume 180 cfm Regeneration volume 75 cfm External static: .2 in wc

4.3 CAPACITY DIAGRAM

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The information contained in this manual is believed to be accurate by NovelAire Technologies, but is not warranted.

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10132 Mammoth Drive Baton Rouge, LA 70814-4420 Phone: (800) 762-1320 (225) 924-0427 Fax: (225) 930-0340 Website www.novelaire.com E-mail: novelair@novelaire.com

Revision 2010-07-20