Nordson NH-4 Reference guide

NH-4 Heaters
Customer Product Manual
Part 1602369-03
Issued 02/20
NORDSON CORPORATION •AMHERST, OHIO •USA
C
APPROVED
US
FM
For parts and technical support, call the Industrial Coating
Systems Customer Support Center at [phone] or
contact your local Nordson representative.
This document is subject to change without notice.
Check http://emanuals.nordson.com for the latest version.

Part 1602369-03 E2020 Nordson Corporation
Table of Contents
Safety 1.......................................
Qualified Personnel 1.........................
Intended Use 1..............................
Regulations and Approvals 1..................
Personal Safety 2............................
High-Pressure Fluids 2.....................
Fire Safety 3................................
Halogenated Hydrocarbon Solvent Hazards 4.
Action in the Event of a Malfunction 4...........
Disposal 4..................................
Description 5..................................
Theory of Operation 6.........................
Identifying Groups of Heaters 6.................
NH-4 Heater Versions 7.......................
Installation 7..................................
Location and Mounting 7......................
Electrical 8..................................
Fluid Lines and Fittings 9......................
Multiple Heater Installations 10..................
Thermometer Installation 11....................
Filter Installation 12............................
Thermostat Adjustment —
Single Heater Installation 12....................
Thermostat Adjustment —
Multiple Heater Installations 12.................
Operation 13...................................
Safety Precautions 13..........................
Startup 13....................................
Thermostat Adjustments 14....................
Shutdown 14..................................
Daily Maintenance 15..........................
Troubleshooting 16.............................
Repair 17......................................
Thermostat Replacement 17....................
Thermostat Removal 17.....................
Thermostat Installation 17...................
Heat Limiter Replacement 19...................
Heater Cartridge Replacement 19...............
Fluid Heating Reservoir Replacement 19.........
Fluid Heating Reservoir Removal 20...........
High Pressure Housing Removal −
Standard Heaters Only 21..................
Fluid Heating Reservoir Installation 21.........
Parts 22.......................................
Heater Reference Chart 22.....................
Standard NH-4 Heaters 24.....................
115 Volt: Single Passage — 1700 watts 24.....
115 Volt: Twin Passage — 500 watts 26.......
115 Volt: Twin Passage — 1000 watts 28......
200 Volt: Single and
Twin Passage — 1700 watt 30...............
200 Volt: Single Passage —
Japan Only — 1700 watt 32.................
200 Volt: Twin Passage —
Japan Only — 1700 watt 34.................
230 Volt: Single Passage — 1700 watt 36.....
230 Volt: Twin Passage — 1000 watt 38.......
230 Volt: Twin Passage — 1700 watt 40.......
380 Volt: Single Passage and
Twin Passage — 1700 watt 42...............
460 Volt: Single and Twin Passage —
1700 watt 46.............................
Stainless Steel NH-4 Heaters 48................
115 Volt: Single Passage — 1700 watt 48......
230 Volt: Single Passage — 1700 watt 50.....
380 Volt: Single Passage — 1700 watt 52.....
460 Volt: Single Passage −1700 watt 54.......
200 Volt: Single Passage —
Japan Only — 1700 watt 56.................
Kits and Spare Parts 57........................
Standard NH-4 Thermostat/Heat Limiter Kit 57..
Standard NH-4 Thermostat Kit 57.............
Stainless Steel NH-4 Thermostat/Heat
Limiter Kit 57..............................
External Adjust Kit 58........................
Manual Reset Thermostat Kit — Japan Only 58.
Standard NH-4 Single Passage
Fluid Reservoir Seal Kit 58..................
Standard NH-4 Twin Passage
Fluid Reservoir Seal Kit 58..................
Stainless Steel Alternate Fitting 58............
Heater Cartridges (Standard and
Stainless Steel Heaters) 59..................
Recommended Spare Parts 59..................
Contact Us
Nordson Corporation welcomes requests for information, comments, and
inquiries about its products. General information about Nordson can be
found on the Internet using the following address:
http://www.nordson.com.
Address all correspondence to:
Nordson Corporation
Attn: Customer Service
555 Jackson Street
Amherst, OH 44001
Notice
This is a Nordson Corporation publication which is protected by copyright.
Original copyright date 2013. No part of this document may be
photocopied, reproduced, or translated to another language without the
prior written consent of Nordson Corporation. The information contained
in this publication is subject to change without notice.
Trademarks
Nordson and the Nordson logo are registered trademarks of Nordson
Corporation.
All other trademarks are the property of their respective owners.

Change Record i
Part 1602369-03
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Change Record
Revision Date Change
01 02/13 Released
02 03/17 Updated DOC and labels.
03 02/20 Added NH-4 heaters to parts list: 1617936, 1617938, 1617937, 1617939.

Change Record
ii
Part 1602369-03 E2020 Nordson Corporation

NH-4 Fluid Heaters 1
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NH-4 Fluid Heaters
Safety
Read and follow these safety instructions. Task- and equipment-specific
warnings, cautions, and instructions are included in equipment
documentation where appropriate.
Make sure all equipment documentation, including these instructions, is
accessible to persons operating or servicing equipment.
Qualified Personnel
Equipment owners are responsible for making sure that Nordson equipment
is installed, operated, and serviced by qualified personnel. Qualified
personnel are those employees or contractors who are trained to safely
perform their assigned tasks. They are familiar with all relevant safety rules
and regulations and are physically capable of performing their assigned
tasks.
Intended Use
Use of Nordson equipment in ways other than those described in the
documentation supplied with the equipment may result in injury to persons
or damage to property.
Some examples of unintended use of equipment include
Susing incompatible materials
Smaking unauthorized modifications
Sremoving or bypassing safety guards or interlocks
Susing incompatible or damaged parts
Susing unapproved auxiliary equipment
Soperating equipment in excess of maximum ratings
Regulations and Approvals
Make sure all equipment is rated and approved for the environment in which
it is used. Any approvals obtained for Nordson equipment will be voided if
instructions for installation, operation, and service are not followed.

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Personal Safety
To prevent injury follow these instructions.
SDo not operate or service equipment unless you are qualified.
SDo not operate equipment unless safety guards, doors, or covers are
intact and automatic interlocks are operating properly. Do not bypass or
disarm any safety devices.
SKeep clear of moving equipment. Before adjusting or servicing moving
equipment, shut off the power supply and wait until the equipment
comes to a complete stop. Lock out power and secure the equipment to
prevent unexpected movement.
SRelieve (bleed off) hydraulic and pneumatic pressure before adjusting or
servicing pressurized systems or components. Disconnect, lock out,
and tag switches before servicing electrical equipment.
SWhile operating manual spray guns, make sure you are grounded.
Wear electrically conductive gloves or a grounding strap connected to
the gun handle or other true earth ground. Do not wear or carry metallic
objects such as jewelry or tools.
SIf you receive even a slight electrical shock, shut down all electrical or
electrostatic equipment immediately. Do not restart the equipment until
the problem has been identified and corrected.
SObtain and read Safety Data Sheets (SDS) for all materials used.
Follow the manufacturer’s instructions for safe handling and use of
materials, and use recommended personal protection devices.
SMake sure the spray area is adequately ventilated.
STo prevent injury, be aware of less-obvious dangers in the workplace
that often cannot be completely eliminated, such as hot surfaces, sharp
edges, energized electrical circuits, and moving parts that cannot be
enclosed or otherwise guarded for practical reasons.
High-Pressure Fluids
High-pressure fluids, unless they are safely contained, are extremely
hazardous. Always relieve fluid pressure before adjusting or servicing high
pressure equipment. A jet of high-pressure fluid can cut like a knife and
cause serious bodily injury, amputation, or death. Fluids penetrating the
skin can also cause toxic poisoning.
If you suffer a fluid injection injury, seek medical care immediately. If
possible, provide a copy of the SDS for the injected fluid to the health care
provider.

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The National Spray Equipment Manufacturers Association has created a
wallet card that you should carry when you are operating high-pressure
spray equipment. These cards are supplied with your equipment. The
following is the text of this card:
WARNING: Any injury caused by high pressure liquid can be serious. If
you are injured or even suspect an injury:
SGo to an emergency room immediately.
STell the doctor that you suspect an injection injury.
SShow him this card
STell him what kind of material you were spraying
MEDICAL ALERT—AIRLESS SPRAY WOUNDS: NOTE TO PHYSICIAN
Injection in the skin is a serious traumatic injury. It is important to treat the
injury surgically as soon as possible. Do not delay treatment to research
toxicity. Toxicity is a concern with some exotic coatings injected directly into
the bloodstream.
Consultation with a plastic surgeon or a reconstructive hand surgeon may
be advisable.
The seriousness of the wound depends on where the injury is on the body,
whether the substance hit something on its way in and deflected causing
more damage, and many other variables including skin microflora residing
in the paint or gun which are blasted into the wound. If the injected paint
contains acrylic latex and titanium dioxide that damage the tissue’s
resistance to infection, bacterial growth will flourish. The treatment that
doctors recommend for an injection injury to the hand includes immediate
decompression of the closed vascular compartments of the hand to release
the underlying tissue distended by the injected paint, judicious wound
debridement, and immediate antibiotic treatment.
Fire Safety
To avoid a fire or explosion, follow these instructions.
SGround all conductive equipment. Use only grounded air and fluid
hoses. Check equipment and workpiece grounding devices regularly.
Resistance to ground must not exceed one megohm.
SShut down all equipment immediately if you notice static sparking or
arcing. Do not restart the equipment until the cause has been identified
and corrected.
SDo not smoke, weld, grind, or use open flames where flammable
materials are being used or stored.
SDo not heat materials to temperatures above those recommended by
the manufacturer. Make sure heat monitoring and limiting devices are
working properly.

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Fire Safety (contd)
SProvide adequate ventilation to prevent dangerous concentrations of
volatile particles or vapors. Refer to local codes or your material SDS
for guidance.
SDo not disconnect live electrical circuits when working with flammable
materials. Shut off power at a disconnect switch first to prevent
sparking.
SKnow where emergency stop buttons, shutoff valves, and fire
extinguishers are located. If a fire starts in a spray booth, immediately
shut off the spray system and exhaust fans.
SShut off electrostatic power and ground the charging system before
adjusting, cleaning, or repairing electrostatic equipment.
SClean, maintain, test, and repair equipment according to the instructions
in your equipment documentation.
SUse only replacement parts that are designed for use with original
equipment. Contact your Nordson representative for parts information
and advice.
Halogenated Hydrocarbon Solvent Hazards
Do not use halogenated hydrocarbon solvents in a pressurized system that
contains aluminum components. Under pressure, these solvents can react
with aluminum and explode, causing injury, death, or property damage.
Halogenated hydrocarbon solvents contain one or more of the following
elements:
Element Symbol Prefix
Fluorine F “Fluoro-”
Chlorine Cl “Chloro-”
Bromine Br “Bromo-”
Iodine I “Iodo-”
Check your material SDS or contact your material supplier for more
information. If you must use halogenated hydrocarbon solvents, contact
your Nordson representative for information about compatible Nordson
components.
Action in the Event of a Malfunction
If a system or any equipment in a system malfunctions, shut off the system
immediately and perform the following steps:
SDisconnect and lock out system electrical power. Close hydraulic and
pneumatic shutoff valves and relieve pressures.
SIdentify the reason for the malfunction and correct it before restarting the
system.
Disposal
Dispose of equipment and materials used in operation and servicing
according to local codes.

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Description
The Model NH-4 heaters are electrically operated, explosion-proof,
high-pressure fluid heaters, designed for use with both air and airless spray
systems.
1
2
3
4
5
6
Model NH-4 Heater
P/N S/N
Volts AC
Watts
Amperes
Phase 50/60 Hz
Maximum operating pressure
Operating temperature range T3C
Minimum Grade for socket head
screws in cover is Class 12.9.
PSIBAR
Nordson Cororation Amherst Ohio 44001 USA
II 2 G
1180
BAS00ATEX2170
WARNING
DO NOT OPEN WHEN
ENERGIZED OR WHEN
EXPLOSIVE ATMOSPHERE
IS PRESENT Ex db IIB T3 Gb
Figure 1 NH-4 ATEX Heaters
1. Enclosure cover
2. Fluid outlet
3. High-pressure housing
4. Fluid inlet
5. Fluid passage body
6. Electrical enclosure
See Figure 1. The standard NH-4 heater is available in both aluminum and
stainless steel versions. Refer to the Parts section for a complete listing of
available heaters.
The heater can be wall or dolly mounted. The heater consists of an
electrical enclosure (6) and a fluid section. The electrical enclosure
contains a thermostat adjustment for the heater. Most versions of the NH-4
heater have internal thermostat controls so you must remove the enclosure
cover (1) in order to change the setting.
The fluid section consists of a fluid passage body (5) and high-pressure
housing (3). The thermostat probe, heater cartridge, and heat limiter are
located within the fluid passage body.

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Theory of Operation
See Figure 2. The heater cartridge heats the fluid passage body (6).
Coating material flows through the inlet port (4) and the spiral passages in
the fluid passage body where it is heated then exits through the outlet
port (8).
An adjustable thermostat (7) controls the temperature. If the thermostat
fails, causing an over-temperature condition, the heat limiter (1) will sense
the excess heat and open the circuit to the heater cartridge, shutting down
the heater.
1
2
3
5
6
7
8
4
Figure 2 Cutaway View of Heater Components
1. Heat limiter
2. Spiral grooves
3. Heater cartridge
4. Inlet port
5. High-pressure housing
6. Fluid passage body
7. Thermostat
8. Outlet port
Identifying Groups of Heaters
This manual covers different types of NH-4 heaters. When procedures or
data differs, the following codes will be used:
[EXT ADJ]—This code is used for NH-4 heaters that have an external
adjustable thermostat control.
[INT ADJ]—This code is used for NH-4 heaters that have an internal
adjustable thermostat control.
[ST STL]—This code is used for stainless steel NH-4 heaters.

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NH-4 Heater Versions
Refer to the Parts section for descriptions, specifications, and part numbers
of available NH-4 heaters.
Installation
WARNING: Allow only qualified personnel to perform the following tasks.
Follow the safety instructions in this document and all other related
documentation.
WARNING: All ATEX approved heaters have a torque specification for the
enclosure cover bolts of 1.11−1.66 kgSm (8−12 ft-lbs). Before installing the
cover make sure it and the top of the enclosure are clean and free of dirt
and debris. Use only bolts of the grade specified on the equipment label.
Tighten the bolts to the torque specification.
WARNING: The purchaser should make the manufacturer aware of the
external effects or aggressive substances that the equipment may be
exposed to.
Location and Mounting
WARNING: Installation must be performed by a qualified electrician and
conform to all federal, state and local codes.
See Figure 3.
Mount the NH-4 heater in a vertical position on a wall or panel, allowing
adequate surrounding space to perform periodic maintenance. Always
locate the heater as close to the spray operation as possible.
NOTE: All ATEX approved NH-4 heaters include a kit with several labels in
different languages. Choose and install the appropriate language label for
your NH-4 heater.

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3/4NPT
Both sides
433 mm
(17.86 in.)
84 mm
(3.307 in.)
149 mm
(5.866 in.)
57 mm
(2.25 in.)
232 mm
(9.13 in.)
98 mm
(3.54 in.)
22 mm
(0.875 in.)
Single passage
3/8NPTF
Twin passage
1/2NPTF
Single passage
3/8NPTF
Twin passage
1/2NPTF
4 Holes
ø9.5 mm
(ø0.374 in.)
41.5 mm
(1.63 in.)
Outlet
Inlet
Figure 3 NH-4 Heater Dimensions
Electrical
WARNING: Install a power isolation device or disconnect in the service line
ahead of the heater to prevent electrical shock during installation or
servicing.
1. Remove the enclosure cover.
2. Route the power supply wiring (recommended 12 AWG, 90 _C (195 _F))
into the electrical enclosure and connect the L1 (power) and L2 (neutral)
leads to the terminal block. Install the ground wire to the electrical
enclosure internal ground stud.
3. Make sure the enclosure cover and top of the enclosure are clean and
free of dirt and debris. Install the enclosure cover and tighten the bolts
to 1.11−1.66 kgSm (8−12 ft-lbs).
4. Install the ground cable to the external ground stud and clamp the cable
to a true earth ground.

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L1 L1 L2
L2
DUAL HOOK−UP
SINGLE PHASE
TRIPLE HOOK−UP
SINGLE PHASE
SINGLE HOOK−UP
SINGLE PHASE
DUAL HOOK−UP
THREE PHASE
TRIPLE HOOK−UP
THREE PHASE
L1
L2
L1
L2
L1 L2 L1 L2 L1 L2
L1
L2
L1 L2
L3
L1 L2
L1
L2
L1 L2
L3
L1 L2 L1 L2
L1
L2
Figure 4 NH-4 Heater Wiring Diagrams
Fluid Lines and Fittings
CAUTION: The heater inlet and outlet fittings use O-ring seals which form
a leak-proof hydraulic seal if tightened properly. To prevent damage to the
seals, do not over-tighten fittings.
1. Install the fluid inlet fitting to the fluid inlet port. Tighten the fluid inlet
fitting to 2.08 kg (15 ft-lb).
2. Install the fluid outlet fitting to the fluid outlet port. Tighten the fluid outlet
fitting to 2.08 kg (15 ft-lb).
3. Install the high-pressure fluid line from the pump to the heater fluid
inlet fitting.

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Multiple Heater Installations
Configure multiple heater installations in a series or parallel.
See Figure 5. Install the heaters in series for all general finishing
applications, except for those with very viscous materials or extremely high
flow rates, such as continuous coaters.
Figure 5 Series Installation
See Figure 6. Install the heaters in parallel for very viscous materials or
extremely high flow rate applications. In parallel systems the length of the
hose between the manifold and the heaters must not exceed 0.91 m (3 ft).
0.91 m (3 ft)
Max.
0.91 m (3 ft)
Max.
Figure 6 Parallel Installation

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Thermometer Installation
Install the thermometer at the heater outlet port, or at the filter outlet port.
The installation kit furnished with the heater includes the fittings necessary
for either installation.
See Figure 7.
1. Install the close nipple (6) in the heater output port, or hex nipple (6) to
the filter output port.
CAUTION: Use the stainless steel thermometer and fittings with the
stainless steel NH-4 heater to prevent damage to the equipment.
NOTE: If the thermometer is installed after the filter, use the hex nipple
included with the heater installation to install the adapter to the filter.
2. Install the applicable thermometer adapter (2 or 5) to the nipple.
3. Install the thermometer (1) to the thermometer adapter.
4. Install the elbow (3) to the thermometer adapter.
5. Connect the high-pressure fluid line to the thermometer adapter elbow.
6. Make sure all fittings are tightened securely.
1
2
6
1
5
6
3
3
4
4
Figure 7 Thermometer Installation
1. Thermometer
2. Standard and stainless steel
thermometer adapter
3. Elbow
4. To filter inlet port
5. Twin passage thermometer adapter
6. Nipple

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Filter Installation
Most coating materials and compounds eventually leave residual deposits
on the inside walls of the heater. These deposits may separate from the
heater as small flakes or granules, which then pass through the system and
cause nozzle or fluid tip plugging. To prevent this from happening, install a
filter between the heater and the first spray gun in the system.
Use insulated or uninsulated high-pressure fluid hose or seamless steel
tubing to connect the heater to the filter assembly. The selection of fluid
line, length, and routing (hung on a wall, laid on the floor, etc.) will have a
direct effect on thermostat setting and fluid temperature at the spray gun. It
is extremely important to place the heater and filter as close to the spray
operation as possible.
Thermostat Adjustment — Single Heater Installation
Adjust the thermostat to provide a starting point temperature for heater
operation. Refer to the Operation section for adjustment procedures to
obtain the desired fluid temperature.
1. Ensure the power is removed from the heater.
NOTE: Rotating the thermostat control clockwise increases the heater
temperature. Rotating the thermostat control counter-clockwise decreases
the heater temperature.
2. [EXT ADJ] Adjust the thermostat control to mid-range.
[INT ADJ] Remove the enclosure from the heater, adjust the thermostat
control to mid-range and install the cover. Tighten the cover bolts to
1.11−1.66 kgSm (8−12 ft-lbs).
Thermostat Adjustment — Multiple Heater Installations
Adjust each thermostat to provide a starting point temperature for operation.
Refer to the Operation section for adjustment procedures to obtain the
desired fluid temperature.
1. Ensure the power is removed from the heaters.
NOTE: Rotating the thermostat control clockwise increases the heater
temperature. Rotating the thermostat control counterclockwise decreases
the temperature.
NOTE: The heater in the flow system that provides the final fluid output to
the filter is the last heater.
2. [EXT ADJ] Adjust the thermostat control on the last heater to mid-range.
Turn the thermostat controls on the remaining heaters fully
counterclockwise.
[INT ADJ] Remove the enclosure covers from the heaters. Adjust the
thermostat control on the last heater in the system to mid-range. Turn
the thermostat control on remaining heaters fully counterclockwise.
Install the enclosure covers and tighten the cover bolts to
1.11−1.66 kgSm (8−12 ft-lbs.

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Operation
WARNING: Allow only qualified personnel to perform the following tasks.
Follow the safety instructions in this document and all other related
documentation.
WARNING: This equipment can be dangerous unless it is used in
accordance with the rules laid down in this manual.
This section covers safety precautions, and single and multiple heater
operation procedures for the NH-4 heater. When a procedure is only
applicable to a particular model it is identified with a code. Refer to the
Description section for an explanation of these codes.
Safety Precautions
Observe the following safety precautions when operating a system with a
heater.
WARNING: Make sure all equipment in the spray area is properly
grounded. Periodically check grounds. Sparks, which can result in poor
grounds, can cause fires or explosions.
WARNING: Inspect and maintain fire detection systems and interlocks
daily.
Refer to the Safety section for additional safety precautions.
Startup
WARNING: Do not operate the heater until the fluid system is fully
pressurized and circulating. Failure to observe this warning can cause
damage to the heat limiter or heater.
1. Make sure that the heater is securely connected to a true earth ground.
2. Tighten all heater fittings securely before starting the pump.
3. Start the pump. Refer to the applicable pump manual for starting
procedures.
4. Adjust the pump to 8−10 strokes per minute. Refer to the applicable
pump manual for adjusting procedures.
WARNING: Before applying power to the heater, make sure all conductive
objects in the spray area are properly grounded. Electrical sparks
discharged from ungrounded conductive objects may start fires or cause
explosions.
5. Apply power to the heater.
6. Allow the fluid temperature to stabilize.

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Thermostat Adjustments
[EXT ADJ] If the thermometer is not indicating the desired temperature,
adjust the thermostat control. If using multiple heaters, adjust the last
heater before the filter until the desired temperature is obtained, then adjust
the thermostats on the remaining heaters to the same setting.
[INT ADJ] If the thermometer is not indicating the desired temperature,
proceed as follows:
1. Remove the power from the heater(s).
WARNING: Make sure the spray activity is not in progress while the
enclosure cover is removed from the heater. Failure to observe this warning
may result in fire or explosion.
2. Remove the enclosure cover from the heater(s).
3. Adjust the thermostat control. If using multiple heater installation, adjust
the thermostat of the last heater before filter to midrange and all other
heaters to zero (extreme counterclockwise position).
4. Apply power to the heater(s) and observe the thermometer.
5. Repeat steps 1 through 4 until the desired fluid temperature is indicated
on the thermometer. If using multiple heaters, adjust thermostat controls
on the remaining heaters to the same setting as the last heater, and
replace covers.
NOTE: If the temperature appears to vary slightly during spraying
operation, adjust the thermostat control on the last heater. Refer to step 5.
NOTE: Consider the following if it is necessary to adjust the thermostat at
the extreme high range in order to maintain the proper fluid temperature:
SReplace the hose with an insulated hose
SRelocate the hose or heater
SInstall an additional NH-4 heater assembly
Shutdown
CAUTION: Always shut down the heater and continue to circulate coating
material through the heater as it cools to avoid material curing inside the
heater fluid passages. Cured coating materials can clog the heater and
damage it.
1. Remove power from the heater 1−15 minutes before shutting down the
pump.
2. Shut down the pump. Refer to the applicable pump manual for
shutdown procedures.

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Daily Maintenance
WARNING: Allow only qualified personnel to perform the following tasks.
Follow the safety instructions in this document and all other related
documentation.
WARNING: Use appropriate respiratory and skin protection when using
coating materials and solvents. Obtain and read the Material Data and
Safety Sheets from the manufacturer before use, and follow manufacturer’s
recommended handling and disposal procedures.
1. Remove paint with a solvent soaked cloth. Do not soak any component
in solvent. O-rings may be affected by some solvents.
2. Make sure fittings are tightened securely.
3. Tighten the tube fittings for the stainless heater inlet and outlet ports to
their original position as follows:
a. Make sure the tubing is resting firmly on the shoulder of fitting.
b. Tighten the nut by hand.
c. Using a wrench, tighten the nut to the original position. An increase
in resistance occurs when the original position has been reached.
d. Tighten the nut slightly.
4. Make sure the heater is grounded.
5. Leave a compatible solvent in the heater when it is not in use.

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Troubleshooting
WARNING: Allow only qualified personnel to perform the following tasks.
Follow the safety instructions in this document and all other related
documentation.
These troubleshooting procedures cover only the most common problems.
If you cannot solve a problem with the information given here, contact your
local Nordson representative for help.
Problem Possible Cause Corrective Action
1. Insufficient heat Faulty thermometer Lightly tap the thermometer to make
sure it is not giving an erratic reading.
If an erratic reading still exists,
replace the thermometer.
Demand is exceeding the capacity
of the heater
Make sure the heating capacity is not
being exceeded. A single heater has
the capacity to raise the temperature
of most organic solvent type coating
materials 56 _C (100 _F) at a flow
rate of 45 l/hr (12 gph). A
temperature rise greater than 56 _C
(100 _F) would proportionately
decrease the capacity of the heater.
Coating material is baked on the
inside of the fluid passage body
For stainless steel heaters:
Flush the heater with a compatible
solvent. If the heat output is not
sufficient after flushing it out, replace
the fluid reservoir.
For all other heaters:
Disassemble the heater and clean the
fluid passage body. Refer to the
Repair section or the Disassembly
Tool Kit section for more information.
2. No heat output Thermostat failed in the on position
causing the heat limiter to open an
electrical circuit to the heater
cartridge
Replace the thermostat and heat
limiter. Refer to the Repair section for
more information.
Heater cartridge failed Refer to the Repair section for more
information. Disconnect the heater
cartridge leads 2 and L2 from the
terminal block. Check for continuity
between the heater cartridge leads
2 and L2. If continuity is not present,
replace the heater cartridge.