EXHeat MFH T4 Guide

Installation, Operation & Maintenance
Instructions Manual
MFH Portable Air Warmer

Page 1of 28
Contents
1. Contact Details.....................................................................................................2
2. Description of Equipment....................................................................................3
3. Preservation and Storage Instructions ..............................................................4
4. Pre-installation Instructions................................................................................6
5. Installation Instructions.......................................................................................8
6. Operating Instructions.......................................................................................11
7. Maintenance Instructions..................................................................................14
8. Special Conditions for use................................................................................ 17
9. Fault Finding, Correction and Spares ..............................................................18
10. COSHH Statement............................................................................................19
11. General Arrangement Drawings......................................................................21
12. Wiring Diagrams...............................................................................................22
13. Routine Maintenance Inspection Record.......................................................25
EXHEAT Industrial can provide versions of this manual in German, French, Italian,
Spanish, Portuguese, Polish, Chinese and Russian. These versions can be requested
at [e-mail]
To maintain the equipment warranty and, if applicable, the Hazardous Area
Certification, the instructions contained within this manual must be complied with in
full.
Fitting any other device invalidates the hazardous area certification.

1. Contact Details
Page 2of 28
1. Contact Details
Sales Enquiries
EXHEAT Industrial Ltd
Threxton House
Threxton Road Industrial Estate
Watton, Thetford
Norfolk, IP25 6NG
Tel: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.exheat-industrial.com
Technical Support
EXHEAT Industrial Ltd
Threxton House
Threxton Road Industrial Estate
Watton, Thetford
Norfolk, IP25 6NG
Tel: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.exheat-industrial.com

2. Description of Equipment
Page 3of 28
2. Description of Equipment
This MFH portable fan heater range offers a compact high capacity air heating solution that is suitable
for small and medium sized premises, and is designed for flexibility, allowing it to be supplied
according to our clients’ capacity and power supply requirements.
Certification
The full range of MFH portable fan heaters are supplied with both ATEX
and IECEx certification.
ATEX IECEx
II 2 G D Ex h
Ex db eb IIB+H2 T3-T4 Gb
Ex tb IIIC T200°C – T135°C Db
Certificate No:
ITS 17 ATEX 101743 X
Ex db eb IIB+H2 T3-T4 Gb
Ex tb IIIC T200°C – T135°C Db
Certificate No:
IECEx ITS 17.0012 X
The Heater Range
MFH T4 MFH T3
Voltage
Duty
Voltage
Duty
110 2.5kW 220
240
380
415
5.5kW
220
240
380
415
2.75kW
120
230
254
277
400
440
480
3kW
230
254
277
400
440
480
600
690
6kW
600
690 3.7kW
The model number is defined as MFH-Duty-Voltage. E.g. MFH-5.5-415
Performance Data
50 Hz 60 Hz
Air Flow 1050 m³/hr 1260 m³/hr
Face Air Velocity 3.6 m/s 4.3 m/s
Fan Speed 1380 rpm 1460 rpm
Motor Rating 0.09 kW 0.09 kW
T Delta T3 – up to 18°C
T4 – up to 10°C T3 – up to 15°C T4 – up to 9°C
Specifications
Dimensions Length: 475mm Width: 470mm
Height: 530mm Packing Length: 480
Width: 480
Height: 540
Weight
(Heater only) 28kg Incl. Packing
(Box) 30kg

Page 4of 28
Materials of
Construction Casing Aliphatic Polyamide (PA66) with EMI
shielding offering excellent resistance to
Hydrocarbons
Flameproof Enclosure Hard Anodised Aluminium offering great corrosion and wear resistance suitable for
both onshore and offshore applications.
Increased Safety Enclosure Stainless Steel fitted with Silicone Sponge
gaskets.
Heating Elements Stainless Steel sheathed tubular element with fully brazed individual stainless steel
fins.
Motor Housing Epoxy Coated Aluminium suitable for both
onshore and offshore applications.
Impeller Epoxy Coated Aluminium hub Aliphatic Polyamide (PA66) with EMI
shielding
Fasteners Stainless Steel Gr. A4-70
Optional Isolator Epoxy Coated Aluminium
Other information
Ingress Protection IP65
Applicable Standards
EN IEC 60079-0
EN IEC 60079-1
EN IEC 60079-7
EN IEC 60079-31
EN 80079-36
EN 80079-37
EN 14986
2. Description of Equipment

3. Preservation and Storage Instructions
Page 5of 28
3. Preservation and Storage Instructions
•Do not remove the heater from its packing until you are ready to assemble and
operate it for the first time.
•After use, store the equipment in an inside location that is dry, clean and well
ventilated.
•Always allow the heater to cool (approx. 20min) before moving it to operate in
another location, transport or store.
•Suitable preservation materials, such as silica gel bags or equivalent, have been
placed inside the packaging and inside the enclosure. Additionally, spare silica gel
bags, or equivalent, can be purchased by contacting EXHEAT Industrial Ltd.
CAUTION – The following preservation instructions must be adhered to, failure
to do so could result in the equipment warranty being invalidated:
•Store the equipment at between 0°C and +40°C.
•Do not store the equipment for more than 3 months unless packed for long term
storage.
•If the equipment is stored beyond 3 months, ensure that preservation materials are
inspected and replaced if required.
CAUTION – It is the client’s responsibility to ensure that, if the terminal
enclosure is opened prior to installation; when refitting the terminal enclosure
lid please ensure the gaskets are not damaged or moved in any way, please
refer to section 5.
•Protect the equipment against additional external sources of vibration and/or impact.
•All fasteners are made from Stainless Steel Gr. 316 to prevent corrosion.

4. Pre-installation Instructions
Page 6of 28
4. Pre-installation Instructions
Unpacking
•Carefully remove the packaging from each product and check for damage.
Immediately report any damage to EXHEAT Industrial Ltd (please keep this IOM and
the additional certification booklet for future reference).
•Remove the heater using the handle provided and place on the ground, remove any
optional extras from the box and discard the packaging responsibly.
•Visually inspect the heater casing for damage. Again, report any damage to EXHEAT
Industrial Ltd straight away.
•Carefully lift the heater onto a bench or workspace then gently lay the heater on its
side to gain access to the enclosures underneath.
Before carrying out the following inspections, ensure no attempt is made to
connect a power supply to the heater. The following instructions may only be
completed while the heater is completely isolated from a source of power.
Pre-Installation Inspection
•Each heater is manufactured to the highest
standard with great care and quality materials.
All the goods are thoroughly inspected and
tested before leaving the manufacturing plant,
and they must be handled with care during
storage and installation.
•Carefully lay the fan heater on its side with the
side entry into the casing facing up.
•If fitted with an optional local isolator, carefully
remove fixing (a.) and loosen fixing (b.) and
slide the enclosure housing towards you. See
Fig 4.1. Rotate so as not to apply any
additional stress on the cable and set down.
See Fig 4.2.
•Remove the four fasteners (c.) and carefully
place the lid to one side so as not to damage
the flamepath.
•Carefully remove the seven fasteners (d.) on
the stainless steel enclosure and remove the
lid. See Fig 4.3.
•If not fitted with an optional local isolator,
remove the seven fasteners (d.) on the
stainless steel enclosure and remove the lid.
Fig 4.1
Fig 4.2

4. Pre-installation Instructions
Page 7of 28
Be careful when removing the fasteners. Failure to replace all correctly prior
to use shall invalidate the certification.
•Before the installation starts it is advised that the product is checked to ensure the
insulation resistance reading is above 2MΩ for the heater when tested at no less
than 500 volts dc. To do this, connect the neutral cable (generally black) to any part
of the steel enclosure, connect the live (generally red) cable to any power terminal
and test for a minimum of 30 seconds.
•Should the product fail this test, please contact the technical help via our website:
www.exheat-industrial.com/contact/support
•Before connecting any supply cables, ensure that the incoming power supply
conforms to the specified voltage on the products nameplate at a nominal variance of
+/- 5% of the specified voltage.
Compliance with these instructions is a warranty requirement. Documented
evidence must be maintained in the form of a signed checklist. Copies of
completed checklists and records will be required in the event of any warranty
claim.
CAUTION – Check the voltage and current of the heater to ensure it is
compatible with the ratings of the supply before energising.
Power Supply
•Only appropriately sized SWA cable can be used on this heater. The cable must also
satisfy the relevant clauses of IEC/EN 60079-14 / Installation requirements.
•The heater supply may derive from;
•suitably rated plug socket,
•suitably rated enclosure with local isolation,
•fixed installation, must be isolatable.
Fig 4.3
Fig 4.4

5. Installation Instructions
Page 8of 28
5. Installation Instructions
•Refer to the relevant code of practice for the equipment:
IEC/EN 60079-14 for selection and installation or the relevant global equivalent.
IEC/EN 60079-17 for inspection and maintenance of electric apparatus for use in
potentially explosive atmospheres or the relevant global equivalent.
•Ensure all pre-installation instructions have been undertaken and that the relevant
documentation has been completed. Failure to do so will invalidate the warranty.
•Ensure that person(s) are suitably competent and authorised to install the equipment
into a hazardous location.
•Ensure the power supply cable is fully isolated from the power source for the duration
of the installation.
•Before operating the equipment, have the installation approved by the site authorised
person who is responsible to ensure that the installed system is safe for operation
•Ensure compliance with any instructions and information provided in this manual and
on the drawings/certification supplied, also be aware of any additional warning that
may be present on the product on any warning labels.
•At no time is the ambient temperature to be allowed to rise above the heaters
certified limit, please check the sales literature and certification for this ambient
range.
•Before energising the product, ensure that the power supply conforms to the
specified voltage on the products nameplate at a nominal variance of +/- 5% of the
specified voltage.
•No additional cable entries are to be made within the terminal box. Only EXHEAT
Industrial Ltd. can facilitate this.
Should deviation from original design parameters occur, or change of
original design structure be required, please refer back to EXHEAT Industrial
Ltd for consultation prior to installation.
No alterations are permitted to the factory installed wiring.
It is the user’s responsibility to ensure that safe systems of work are used by
all personnel operating and maintaining the equipment, including testing
when ‘live’.
If there is any uncertainty about these points, contact EXHEAT
Industrial Ltd
for advice.
Failure to comply could result in the Hazardous Area Certificate being
invalidated.

5. Installation Instructions
Page 9of 28
Electrical Supply Connection with Optional Local Isolator fitted.
•Refer to the wiring diagram in Section 12.
•Cable entry to the optional local isolator is via 1 off pre drilled M32x1.5p hole and
fitted with a temporary plastic plug. Remove the plug and install the cable and gland
as per manufacturer’s instructions.
•Connect the Live connection(s), Neutral and Earth in accordance with the appropriate
wiring diagram in Section 12.
•The Live and Neutral connections to the heaters are made using the installed
terminals and by the use of proprietary ferrule crimps (client supplied). The isolator
can accept a maximum cable size of 25mm². Torque to 2N.m.
•Optionally, the external earth connection is made by use of proprietary ring crimps to
suit an M6 fixing and to suit the size of cable installed. This is found adjacent to the
cable entries.
•With the connections made, replace the enclosure lids securely with all fasteners.
•When replacing the Isolator, ensure the cable is looped around the bracket to prevent
snagging.
Electrical Supply Connection without Optional Local Isolator fitted.
•Refer to the wiring diagram in Section 12.
•Cable entry to the main terminal enclosure is via 1 off M20 Certified cable gland (not
supplied).
•Connect the live connection(s), neutral and earth in accordance with the appropriate
wiring diagram in Section 12.
•The live and neutral connections to the heaters are made using the installed
terminals and by the use of proprietary ferrule crimps (client supplied). The terminals
can accept a maximum cable size of 10mm² and must be tightened to 1.2N.m min /
1.9N.m max.
•Optionally, the external earth connection is made by use of proprietary ring crimps to
suit an M6 fixing and to suit the size of cable installed. This is found adjacent to the
cable entries.
•With the connections made, replace the enclosure lids securely with all fasteners to
5N.m min.
Ensure that the connections are made in accordance with site philosophy. If using
ferrules, a minimum of 5.5mm must be engaged within the terminals. If using multi-
stranded cable, the stripping length should be 12mm. No modification to allow other
connections is permitted.
DO NOT ENERGISE THE HEATER AT THIS TIME
DO NOT ENERGISE THE HEATER AT THIS TIME

5. Installation Instructions
Page 10 of 28
General Installation Instructions
With the power supply cable connected please complete these remaining instructions before
energising.
•Place the heater on its feet in the desired operational location and make further minor
adjustments to each foot as required in order to prevent the heater from rocking.
Failure to do so could cause damage to the heater.
•Ensure the distance between the Isolator and the ground is at least 40mm at all
times.
•The installer and the end user shall ensure that the unit has free and unrestricted air
flow to allow natural convection to occur at all times. DO NOT COVER the heater and
do not allow anything to rest on or against it when in operation.
Terminate / connect the power supply end of the power cable to
the isolated power supply or a certified plug as required.
Warnings
•No additional cable entries are to be made within the terminal box. Only EXHEAT
Industrial Ltd. can facilitate this.
•No alterations are permitted to the factory installed wiring.
•The cable glands installed to the MFH heater should be such that they do not
decrease the IIB + H2 rating of the heater. All cable glands are to be suitable for the
rating and size of the supply cables. IP washers are to be used where applicable.
•Before connection ensure that the supply corresponds with that specified on the
nameplate label, and that the sizes and types of cables to be used are suitably rated
for the load and temperature of the product.
•Each heater circuit must be protected by a suitably rated over current device and
earth leakage circuit breaker device. See below for earth connection details.
•The covers of the MFH range terminal boxes are removed by simply un-bolting the lid
fittings. When re-fitting ensure that any gasket seal is in good condition and correctly
located. The main cover mating faces MUST be kept clean and free from any debris
at all times.
•The installer or end user must connect to the EXHEAT Industrial Ltd designated
terminals within the terminal box - DO NOT disturb factory fitted wiring.

Page 11 of 28
Earth Connections
•When fitted with the optional local isolator, the Client internal earth cable connection
on the MFH heater is inside the Isolator Enclosure. Connection is made by the use of
an M6 earth bolt (fitted) with proprietary cable ring crimp (Client supplied). Maximum
cable size is 25mm².
•When not fitted with the optional local isolator, the Client internal earth cable
connection on the MFH heater is inside the terminal enclosure. Connection is made
by the use of a ferrule crimp (Client supplied) connected to the Earth terminal
provided. Maximum cable size is 10mm², if larger cable is required, an optional local
isolator must be fitted.
•The minimum External Earth conductor size permitted is 4mm². The external earth is
made on the M6 stud on the Ex e enclosure, or optionally on the Isolator bracket
fixings (when fitted)
Earth-fault Protection
For safety reasons, it is essential to limit the magnitude and duration of earth-fault currents.
It is impractical to cover all possible systems, however note that, regardless of which system
is used, the product must be protected by a suitable device wired to shut down the product if
the thermostat fails to earth. Suitable devices include a residual current device (RCD) – this
is the preferred method and should be used whenever possible – or an insulation monitoring
device.
•Maximum recommended setting for the RCD: 100mA/10mS. The duration time of
10mS (ten milliseconds) ensures that any fault is detected within a single cycle of a
thyristor system (where applicable).
•Maximum recommended setting for the insulation monitoring device: Insulation
resistance is not greater than 50 ohms per volt of rated voltage.
Ensure that the equipment is earthed in accordance with the plant earthing philosophy.
If fitted, an anti-condensation heater must be protected by a 30mA earth leakage circuit
breaker.
Before commissioning the equipment, the completed installation should be approved by an
authorised & competent person to ensure that it has been carried out correctly and that the
system is safe for commissioning.
Before switching the thermostat circuit on, check that all the relevant requirements, and any
special conditions of safe use have been adhered to, including any additional warning labels
that may be present on the product itself.
WARNING – These heaters MUST BE EARTHED.
5. Installation Instructions

6. Operating Instructions
Page 12 of 28
6. Operating Instructions
General
Electrical equipment must be designed, tested and installed such that, when it is used
correctly, health and safety risks are kept to a minimum. The user must be provided with
information about any necessary safety conditions, warned of any possible hazards that may
arise during normal operation and told how to avoid them.
The user must ensure that the following is adhered to:
•Any employees working on the equipment are authorised & competent in the proper
working procedures in order to ensure safety. The plant must be maintained in a safe
condition.
•The heater terminal enclosure covers are not to be removed whilst any precipitation,
airborne dust or moisture is in the vicinity or when grinding, welding or similar
activities are taking place nearby.
•The heater terminal enclosure covers are not to be removed whilst the heater is
energised.
•Ensure that all protective packaging is removed carefully and visually inspect product
for any transit damage.
•The heaters must be handled with care and stored in clean and dry conditions, as per
section 3.
•All prevailing rules, regulations and bylaws in force at the time and place of
installation must be observed.
•The heater should be checked for standing stability, adjustments to the feet should
only be made whilst the heater is de-energised.
•All terminal connections made by the installer must be checked for tightness before
energising.
•Refer to the relevant code of practice for the equipment:
•IEC/EN 60079-14 for selection and installation or the relevant global
equivalent.
•IEC/EN 60079-17 for inspection and maintenance of electric apparatus for
use in potentially explosive atmospheres or the relevant global equivalent.
•Precautions must be taken to prevent damage to the cable entries and mating
surfaces of the explosionproof enclosure. Report any damage to EXHEAT Industrial
Ltd as flamepaths are no intended to be repaired.
•Ensure that any special conditions for safe use detailed on the Hazardous Area
Certification are complied with (see additional certification booklet supplied with this
product).
•Any modification not carried out by EXHEAT Industrial Ltd will invalidate certification
and warranty.

6. Operating Instructions
Page 13 of 28
CAUTION – There is the potential for electrostatic discharge and as such, painted
surfaces should only be cleaned with a damp cloth.
Operating Instructions
•The heater is to be used to raise the temperature within a room or local area, by
operating at its rated voltage and duty when required.
•Do not energise the heater until you have completed all steps of section 4 and 5 of
this manual.
•To operate the heater, simply ensure the power is connected and turn the applicable
isolator to the on position.
•The isolator shall be either:
•Local to the heater, when fitted with the optional local isolator
•On the wall socket receptacle when fitted with a certified plug
•At the wall mounted enclosure when hard wired to the supply.
When energising, check that the fan has started to rotate and that air flow is in
the correct direction (See General Arrangement Drawings)
. If either is incorrect
de-energise the heater immediately and look at Section 9 to correct the fault.
•Once installed and the power is energised, no adjustments to the heater are allowed.
•The MFH portable fan heater is designed to operate in ambient temperature range of
-40°C to +40°C and the user must ensure that this maximum ambient temperature is
not exceeded at any time whilst in operation.
•Ensure that while in operation, the air flow is not restricted at either the inlet or outlet
of the heater.
•When no longer required, de-energise the heater and allow to cool.
•Allow the heater to stand for 5 minutes minimum if repositioning locally, otherwise
allow 20 minutes to cool before moving fully, transporting or storing.
•The heater is fitted with an over-temperature protection circuit. To reset this you must
isolate and disconnect fully from the power supply and allow to cool prior to resetting.
To reset the over-temperature protection device:
•Remove the fan guard furthest from the impeller,
•Remove the 6 fasteners on the Ex d enclosure lid, and gently slide out the
control rail which is directly mounted to this lid.
•Switch the MCB to the closed position,
•Carefully slide the lid and rail back in, do not use excessive force as this could
damage the internal cabling,
•Replace all fasteners for the lid and fan guard.

7. Maintenance Instructions
Page 14 of 28
7. Maintenance Instructions
General Safety Precautions
The user must ensure that maintenance, installations, commissioning and testing of the
equipment is only carried out by authorised and competent persons.
The following rules must be adhered to:
•All prevailing site safety regulations shall be adhered to at all times.
•Check for hazardous gases before and during any maintenance activity.
•Fully isolate the equipment from the electrical supply before and whilst any work is
being performed.
•Before starting maintenance work, isolate the equipment completely where possible.
•Before removing the terminal enclosure, allow sufficient time for the internal
components to cool down after electrical isolation.
•Do not work on the equipment when it is energised.
•Be aware of hazards which may arise when working on energised equipment, and
take all necessary precautions.
•Familiarise all persons working on the equipment with the instructions and
information provided within this manual.
The following preventative maintenance should be carried out at the intervals shown below,
for any replacement parts, please contact EXHEAT Industrial Ltd.
Compliance with these maintenance instructions is a mandatory requirement. Documented
evidence must be maintained in the form of a signed checklist. Copies of completed
checklists and records will be required in the event of a warranty claim.
If the heaters are not used for more than three months
they must be tested for
insulation resistance before being energised.
Motor
•Maintenance shall be performed only by qualified people in accordance with the
IEC/EN 60079-17 or national standards (latest edition).
•Qualified people must have knowledge about electrical apparatus for explosive
atmospheres and electrical installations in hazardous areas.
•Every 3000 hours of service verify and restore, if necessary, the grease on the radial
seals (for example the V-rings)
•Periodically (depending on environment and duty) verify:
•Motor cleanliness and free passage of cool air;
•Free motor running with low vibration and absence of anomalous noises,
where there is high vibration and/or noise, verify the motor fastenings,
balance and that the bearings are in good condition.

7. Maintenance Instructions
Page 15 of 28
Every Use
•Generally inspect the equipment for external damage or signs of deterioration.
•Ensure that the product is clear of obstruction and that the airflow remains
unrestricted.
•Check the fan guards, impeller and heating elements for any residual dust build up.
Anything noted must be removed with a damp cloth.
•Check the impeller blades for signs of damage, and that there is at least 2mm of
clearance to the casing and the guard. Any damage should be reported to EXHEAT
Industrial Ltd and the heater taken out of service.
•Check the casing for any signs of contact from the impeller. Any scuffs or marks
made by the impeller should be reported to EXHEAT Industrial Ltd and the heater
taken out of service.
Six-monthly Maintenance Inspections
The following should be undertaken every six months in addition to the maintenance
inspections above:
Do not remove the terminal enclosure cover during wet or humid conditions as
this could lead to a reduction in insulation resistance of the thermostat.
•Ensure the 5mm grub screws that affix the impeller to the motor are tight.
•Remove the fan guard and ensure the blades rotate unimpeded and that there
remains a gap of at least 2mm all the way around.
•Isolate the electrical supply and remove the cover as per section 5.
•Internals should be clean, dry and free from debris, clean using a damp cloth.
•Ensure that electrical terminations are undamaged and secure.
•Measure the overall insulation resistance of the heater. Use a 500V dc Insulation
Resistance Tester to take a reading between the earth and the phase terminals. The
reading should be better than 2 megohm. If it is not, refer to section 4.
•Ensure that the gasket is in good condition and replace if required. Carefully refit the
covers using only the fixings provided, as per section 5.
•Earth continuity must be maintained between all earth points and the main structure,
ensure that any earth conductors are correctly and securely fitted between all earth
points and main structure.

Page 16 of 28
Annual Inspections and Long-Term Storage Inspections
Ensure that the following inspections are carried out if equipment is in storage or in use for a
year or more:
•Maintain preservation as per Section 3
•Undertake the 6-monthly inspections as above.
•Inspect for low insulation resistance, as section 4.
•Only EXHEAT Industrial Ltd can undertake any replacements in hazardous area
equipment, any unauthorised modifications will invalidate the hazardous area
certification and any warranty.
•If equipment is being left unused for a period greater than three months, undertake
the 6-monthly maintenance before energizing.
•Check for component failure in line with section 5, if there is component failure or low
insulation resistance, contact EXHEAT Industrial Ltd for further advice.
Only EXHEAT Industrial Ltd or approved Services Representative are
authorised to replace failed components. The hazardous area certification
and
warranty could be invalidated if this requirement is not strictly observed.
EXHEAT Maintenance
If you are unable to complete any of these maintenance checks, please contact EXHEAT
Industrial Ltd to arrange for any of the relevant maintenance work to be undertaken.
If any problems are noted whilst maintenance checks are being carried out, please contact
EXHEAT Industrial Ltd using the information provided at the beginning of this document.
7. Maintenance Instructions

8. Special Conditions for use
Page 17 of 28
8. Special Conditions for use
These conditions are in addition to those stipulated on the certificate that accompanies this
manual.
In order to allow operation of this heater, please ensure that the following conditions for safe
use are met:
•The heater must not be placed within 0.5m of any wall, structure or other obstruction
to the air inlet (Impeller side), or outlet;
•The heater must not be covered in any way whilst in operation or until fully cooled
after use;
•Before opening any enclosure, removing the fan guards or undertaking any
maintenance, ensure the heater is fully de-energised and has been allowed to cool to
ambient temperatures.
•Only EXHEAT Industrial Ltd supplied parts may be fitted to the heater, this includes
bracketry and ducting.

9. Fault Finding, Correction and Spares
Page 18 of 28
9. Fault Finding, Correction and Spares
MFH Fan Assisted Heater
See Maintenance instructions for procedures relating to these faults.
Fault
Check
Resolution
Vibration
De-energise the heaters
- Ensure that all feet are
properly seated on the
ground and that the heater
is positioned on a clear
and level surface.
- Visually inspect the
impeller and check for
centralised revolution.
- Using a hand spanner, adjust
the legs in turn until the heater
sits on all four feet.
- Remove the fan guards and
casing lid and check that the
impeller grub screws are tight.
The Impeller does
not spin
Immediately isolate the heater from
the power supply.
- Inspect all electrical
connections.
- Open the Ex d enclosure
and check if the MCB is in
the open position.
- Tighten any loose connections.
- Switch the MCB to the closed
position.
The impeller
spins clockwise
(looking from fan
end) (3 Phase
heaters only)
Immediately isolate the heater from
the power supply.
- Access the Ex e enclosure
and ensure that phase
numbering is correct.
- Swap the cables between two
of the incoming phases, L1 and
L2 only.
There is no heat
Isolate the heater from the power
supply.
- Check the wiring of the
heating elements.
- Remove the element
connection cable and
check the resistance values
of each phase.
Ensure you are using the correct wiring
diagram in section 12.
- Tighten any loose connections.
- If an imbalanced reading is
found, or an infinite value,
contact EXHEAT Industrial Ltd.
The Heater
suddenly
de-energises
Immediately isolate the heater from
the power supply.
- Check the ambient has not
exceeded 40°C.
- Check for any signs of
damage.
- Check for any electrical
fault.
- Open the Ex d enclosure
and check if the MCB is in
the open position.
- Undertake a 6 monthly
inspection of the equipment to
ensure no fault.
- Switch the MCB to the closed
position.
A rattle or other
unusual noise
Isolate the heater from the power
supply.
- Check all fasteners are
tight.
- Check for signs of scuffing
between the impeller and
casing.
- Using hand tools, tighten any
loose fasteners.
- Take out of service and contact
Exheat Industrial Limited.

Page 19 of 28
Spares
(Anything not mentioned below will require the unit to be sent back to manufacturer)
Failure Type Meantime Between
Failures Estimated Replacement Time Spares Lead Time
Replacement Feet When Required 10 minutes 1 week
Impeller When Required 45 minutes 1 week
RTD Temperature
Sensor When Required 60 minutes 1 week
Gaskets When Required Up to 2 hours 1 week
Handle / Lid When Required 30 minutes 1 week
9. Fault Finding, Correction and Spares