Durex industries DFX 550 Посібник з монтажу та експлуатації - Сторінка 2

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WARNING!

EXPLOSION & FIRE HAZARD. Avoid installation of

heater near combustible vapors or flammable gas-laden

atmospheres as hot heater surfaces can possibly ignite

the flammable mixtures and cause personal injury and

equipment damage.

EXPLOSION & FIRE HAZARD. The user of this prod-

uct is entirely responsible for determining and comply-

ing with ALL hazardous location classification require-

ments for the application of this product.

BURN HAZARD. Uninsulated DFX heater body (cast-

ing), electrical enclosure and mounting leg parts can

reach temperatures well in excess of 140°F (60°C). User

is responsible for appropriate thermal insulation and

personnel protection to avoid personal injury.

1. Megohm check. Electric heater elements may absorb mois-

ture during shipping and storage. This can cause excessive cur-

rent leakage. Therefore, it is recommended to check the heater

megohm value prior to energizing. A test voltage of 500VDC

should be used between the heater element terminal pin and

heater sheath. A reading of 10 megohms or greater is accept-

able. If a low megohm level is measured, there are two rem-

edies. The best remedy is to remove the electrical enclosure and

termination hardware along with thermostats, sensor and temp

switches. Then place the unit in an oven set at 250°F (120°C) for

a minimum of 8 hours. Remove the heater from the oven and

check the megohm value. Once a minimum of 100 megohms

has been achieved, remove from oven and allow the unit to cool

to room temperature. Then do a final megohm re-check and

proceed with reassembly of enclosure hardware and wiring.

The second remedy is to remove the enclosure cover, connect

wires and power the heater at low voltage (start out at about

¼ of the rated voltage) until an acceptable megohm value is

reached. Ensure the high limit safety device is operating to

prevent an overheat condition. Allow heater body to "soak" at

a temperature of no more than 250°F for about 4 hours.

2. Mount the heater to a structural member using the tapped

holes on the mounting legs (Figure 1). Do NOT use tubing and

tubing connections to support the heater. The structural mem-

ber should have slotted holes on one end to allow for heater

expansion and contraction. Mounting bolts should be torqued

in accordance with SAE standards.

3. DFX heaters MUST be mounted vertically as shown in Figure

2. Regardless of electrical enclosure orientation, ensure that the

lower tube is the flow inlet and the upper tube is the outlet.

190 Detroit Street, Cary, Illinois 60013 • Phone: 847-639-5600 • Fax: 847-639-2199 • Web: www.durexindustries.com • TOLL FREE: 800-762-3468

DFX Cast Circulation Heater

Installation & Operation Manual

INSTALLATION

Enclosure "Down" orientation is recommended for higher

temperature outlet applications (300°F or 150°C+) to reduce en-

closure temperatures. If the heater has a "stand-off" enclosure,

mount the heater vertically with the enclosure up.

4. Ensure enough clearance to easily access electrical enclosure

for service.

5. Connect user supplied tubing to the DFX heater flow tubes

using appropriate connections. Pressure-test the system to

ensure tight, leak-free connections.

6. Protect the electrical enclosure from spray, condensation,

dripping and vapors. The appropriately rated enclosure should

be used if the heater will be subject to these conditions.

7. For DFX 250 heaters only, ensure the electric heater element

is snuggly tightened to the cast heater body.

8. If thermal insulation is not included with the heater, install

appropriate thermal insulation and protective personnel shield-

ing against high surface temperatures that might cause burns

and/or may be too high for the hazardous location classification.

If operating temperatures are expected above 300°F (150°C), it

is recommended to install ceramic or high temperature com-

posite thermal barriers between the heater mounting legs and

customer structural mounting support. This will greatly aid in

reducing conduction heat losses to the frame.

9. Further recommendations: Pumps or blowers should be

installed on the inlet side of the heater. A flow switch is rec-

ommended to prevent operating the heater when flow rate is

insufficient. A suitable filter should be used to prevent flow

tube clogging. A pressure relief valve is also recommended for

higher pressure applications.

Customer

Fabricated

Support

Thread Size & Depth

DFX

Thread

Style

250

#10-32

350/375

¼" - 20

550

¼" - 20

550 L

⅜" - 20

750

½" - 20

Figure 1

Enclosure Up

Enclosure Down

Outlet

Inlet

Figure 2

Thread

Hole

Size

Depth

⅜"

½"

⅜"

½"

⅝"

¾"

1 ⅜"

Outlet

Inlet