Durex industries DFX 750 Series User manual

DFX Cast Circulation Heater
Installation & Operation Manual
190 Detroit Street, Cary, Illinois 60013 • Phone: [phone] • Fax: [phone] • Web: www.durexindustries.com • TOLL FREE: 800-762-3468
1
DFX 250
NEMA 4
Housing
Cartridge
Heater
Heater
Body
Optional TC
Location
DFX 350, 375, 550 and 750 Series
PARTS LIST:
1. Electrical Enclosure
2. Cast Heater Body
3. Connection Fiings
(optional)
4. Thermostat (optional)
5. Sheet Metal Insulation
Jacket (optional)
6. Foam Insulation Sleeve
(optional)
7. Thermocouple (optional)
8. Replaceable Heater
(DFX 250 Only)
BEFORE INSTALLATION
NOTICE!
Read this entire document before installing, operating
or servicing this product. Failure to do so may cause
personal injury and/or equipment damage.
Read all WARNING! messages. They call out impor-
tant safety information to prevent personal injury and/
or equipment damage.
1. Unpack the heater and ensure all parts are included. Consult
Durex Industries for instructions if parts appear to be missing
or if the product appears to be damaged. DO NOT OPERATE
DAMAGED EQUIPMENT.
2. Check nameplate information to ensure the product complies
with the required specications. Contact Durex Industries
if there appears to be an error prior to proceeding with the
installation.
250 NEMA 1 250 NEMA 4 250 NEMA 7 350/375/550 NEMA 1 350/375/550 NEMA 4 350/375/550 NEMA 7
750 NEMA 1 750 NEMA 4 750 NEMA 7
Terminations
NEMA 1
Housing
Heater Body
Note: Number of heater elements varies
depending on model number.

DFX Cast Circulation Heater
Installation & Operation Manual
190 Detroit Street, Cary, Illinois 60013 • Phone: [phone] • Fax: [phone] • Web: www.durexindustries.com • TOLL FREE: 800-762-3468
2
Customer
Fabricated
Support
Figure 1
Thread Size & Depth
DFX
Style
Thread
Size
Thread
Depth
Hole
Depth
250 #10-32 ⅜” ½”
350/375 ¼” - 20 ⅜” ½”
550 ¼” - 20 ½” ⅝”
550 L ⅜” - 20 ¾” 1”
750 ½” - 20 1” 1 ⅜”
WARNING!
EXPLOSION & FIRE HAZARD. Avoid installation of
heater near combustible vapors or ammable gas-laden
atmospheres as hot heater surfaces can possibly ignite
the ammable 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 classication 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 nal 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 sloed 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 ow inlet and the upper tube is the outlet.
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-o” 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 ow 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 classication.
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 ow switch is rec-
ommended to prevent operating the heater when ow rate is
insucient. A suitable lter should be used to prevent ow
tube clogging. A pressure relief valve is also recommended for
higher pressure applications.
INSTALLATION
Inlet
Outlet
Enclosure Up Enclosure Down
Outlet
Inlet
Figure 2

DFX Cast Circulation Heater
Installation & Operation Manual
190 Detroit Street, Cary, Illinois 60013 • Phone: [phone] • Fax: [phone] • Web: www.durexindustries.com • TOLL FREE: 800-762-3468
3
WARNING!
ELECTRIC SHOCK HAZARD. Disconnect power prior
to making (or servicing) wire, cable and conduit con-
nections. Failure to do so may cause personal injury or
equipment damage. Only qualied electricians should
install wiring, and ensure proper grounding, in accor-
dance with the NEC, NFPA 70 and other local codes.
EXPLOSION & FIRE HAZARD. For classied hazard-
ous locations, user must verify that the properly rated
enclosure is being employed and is responsible for
proper eld connections as required by NEC, NFPA70
and other local codes.
EXPLOSION & FIRE HAZARD. A high limit safety de-
vice (preferably FM Approved or similar rating) such as
high limit temperature controller, temperature switch
or other redundant control MUST be used to prevent a
potentially dangerous heater over-temperature condi-
tion. This condition could lead to personal injury and
equipment damage.
1. It is the user’s responsibility to properly size and install
proper feed wire and protective conduit. Due to potentially
high operating temperatures, use minimum 250°C (480°F) rated
power feed wire. Apply appropriate ampacity de-rate factors
to the wire based on expected enclosure operating temperature
conditions. Feeder wire should also be housed in properly
sized and rated conduit.
2. Consult wiring diagrams for wiring connection guidance.
Consult factory if anything is unclear.
3. After heater is wired, check tightness on each terminal by
supporting lower hex nut and tightening upper hex nut to a
maximum torque of 20 in-lb (2.25 N-m). Over tightening will
lead to termination breakage and render heater inoperable!
4. Use copper connector lugs to land power supply wiring (not
applicable to DFX 250). Refer to wiring diagrams for assistance.
5. Ensure that process temperature controllers, high limit con-
trollers and thermocouple(s) are properly wired and connected.
Ensure that the power switching device (relay or SSR) is prop-
erly rated for voltage and current requirements.
6. If using a thermostat, ensure that it is properly wired and
connected. If the thermostat is used as pilot duty, verify proper
wiring to user supplied contactors and eld wiring.
7. Thermostats and temperature controllers should not be used
to “power o” or disconnect power to the the heater. Use of
a disconnect switch or circuit breaker is required to interrupt
power supply to the heater and electrical connections.
WIRING
WARNING!
ELECTRIC SHOCK HAZARD. Disconnect power prior
to servicing wire, cable and conduit connections. Fail-
ure to do so may cause personal injury or equipment
damage. Only qualied electricians should service wir-
ing, and ensure proper grounding, in accordance with
the NEC, NFPA 70 and other local codes.
1. Periodically check high limit functionality as well as tempera-
ture control.
2. Periodically, check electrical connections and retighten those
that may have loosened in service. Replace wires and connec-
tion hardware that appear to be oxidized and which would
interfere with electrical conduction.
3. Periodically disconnect the process ow tube and visually
inspect to ensure no build up or corrosion of the ow tube.
4. If a moisture resistant enclosure, check the gasket condition
and replace if needed.
5. NOTE: Maintenance intervals are to be established by the
user.
MAINTENANCE
WARNING!
EXPLOSION & FIRE HAZARD. Do not operate the
heater at pressures higher than for which it is rated.
Also, do not heat materials that are corrosive to the ow
tubing. The ow tube may rupture potentially causing
personal injury or equipment damage.
1. Establish uid ow. If a liquid, it is preferable to bleed the
air out of the lines if possible.
2. Energize the heater and control system. Set proper tempera-
ture and process parameters. Make sure the system is working
properly before leaving it unaended.
3. Do not allow heater to operate if ow is interrupted or allow
pressure to build up in access of pressure ratings.
OPERATION

DFX Cast Circulation Heater
Installation & Operation Manual
190 Detroit Street, Cary, Illinois 60013 • Phone: [phone] • Fax: [phone] • Web: www.durexindustries.com • TOLL FREE: 800-762-3468
4
WIRING DIAGRAMS
TYPICAL THERMOSTAT WIRING DIAGRAMS
L1
L2
1 Phase 3 Phase, Delta
L1 L2
L3
L1 L2
L3
3 Phase, Wye
DFX 550 and 750, 3 Elements
1 Phase - Pilot Duty
Heating
Elements
Line
120V, 240V, or
480V
Control Volts
120V or 240V
2 Pole ContactorSPST Thermostat
For 120V, 240V, or 480V heaters when current
exceeds thermostat rating
1 Phase - Pilot Duty
Heating
Elements
Line
120V, 240V, or
480V
Control Volts
120V or 240V
2 Pole ContactorDPST Thermostat
For 120V, 240V, or 480V heaters when current
exceeds thermostat rating
DFX 250, Heater Element
3 Phase
L1
L2 L3
1 Phase
L1 L2
DFX 350 and 375, 2 Elements
L1
L2
1 Phase Parallel
L1 L2
1 Phase Series
DFX 750, 6 Elements
L1
L2
L3
3 Phase Delta Series
L1
L2
L3
3 Phase Delta Parallel
L1
L2
L3
3 Phase Wye Parallel
1 Phase - SPST Tstat
Heating
Elements
Line
120V or 240V
1 Phase - DPST Tstat
Heating
Elements
Line
120V, 240V,
or 480V
3 Phase - DPST Tstat
Heating
Elements
Line
120V, 240V, or
480V, 3 Ph
3 Phase - Pilot Duty
Heating
Elements
Control Volts
120V or 240V 2 Pole or
3 Pole Contactor
Line
240V or 480V,
3 Ph
3 Phase - Pilot Duty
Heating
Elements
Control Volts
120V or 240V 2 Pole or
3 Pole Contactor
DPST Thermostat
Line
240V or 480V,
3 Ph
SPST Thermostat
CAST-DFXIM-0613