– Improper installation or repair of Webasto heating and cooling systems can cause fire
or the leakage of deadly carbon monoxide leading to serious injury or death.
– To install and repair Webasto heating and cooling systems you need to have
completed a Webasto training course and have the appropriate technical
documentation, special tools and special equipment. Only genuine Webasto parts
may be used. See also Webasto air and water heaters accessories catalogue.
– Never try to install or repair Webasto heating or cooling systems if you have not
completed a Webasto training course, you do not have the necessary technical skills
and you do not have the technical documentation, tools and equipment available to
ensure that you can complete the installation and repair work properly.
– ALWAYS carefully follow Webasto installation and repair instructions and heed all
WARNINGS.
– Webasto heating and cooling systems require qualified and/or professional
installation and repair technicians. Warranty shall be void if not installed by a
certified or trained installer/repair technician who has successfully completed the
factory training course for installation and repair of Webasto heating and cooling
systems, and has been provided with the technical information, tools and equipment
required to properly complete the necessary installation /repairs.
– Product produces temperatures high enough to ignite surrounding combustible
materials such as inflammable liquids, gases, vapor, and other combustible matter.
The heater must
to prevent the risk of explosion.
be switched off when loading or unloading inflammable materials
www.webasto.us4Webasto Thermo & Comfort N.A., Inc.
Page 4
Thermo Pro 90Safety and General Information
DANGER
WARNING
CAUTION
OR
1.Safety and General Information
1.1Warning Symbols in this Installation Manual
The purpose of safety symbols is to attract your attention to possible hazardous conditions. This manual uses a series of
symbols and signal words which are intended to convey the level of importance of the safety messages. The
progression of symbols is described below. Remember that safety messages by themselves do not eliminate danger and
are not a substitute for proper accident prevention measures.
Indicates an imminently hazardous situation which, if not avoided,
WILL result in death or serious injury.
Indicates a potentially hazardous situation which, if not avoided,
COULD result in death or serious injury.
Indicates a potentially hazardous situation which, if not avoided,
MAY result in minor or moderate injury or property damage.
It may also be used to alert against unsafe practices.
These symbols are used to alert the installer to important or useful information
about proper installation of the equipment.
1.2General Information
Webasto Product North America, Inc. is pleased to provide this installation manual with the Thermo Pro 90 Heater.
When used according to the guidelines stated in this manual, you can expect to provide years of trouble-free, enjoyable
operation for your customer.
This manual represents our latest effort to produce the best technical documentation possible. In our efforts towards
continuous, ongoing product improvement, we encourage our customers to write to us with their comments or
criticisms concerning this manual and the Thermo Pro 90 Heater Installation.
Please write to us at:
Webasto Thermo & Comfort North America, Inc.
Technical Documentation Group
15083 North Road
Fenton, MI 48430
You are also invited to fill out our online questionnaire concerning our technical documentation and web site at:
www.techwebasto.com
If you have any immediate questions concerning this manual, the installation procedures within or the product itself,
please call us at:
(800) 860-7866or send a fax to:(810) 593-6001
www.webasto.us5Webasto Thermo & Comfort N.A., Inc.
Page 5
Regulation for Installation in the VehicleThermo Pro 90
2.Regulation for Installation in the
Vehicle
Read this installation manual in its entirety before
installing this equipment.
2.1Scope
2.1.1Subject to the provisions of paragraph 2.1.2,
internal combustion heaters must be installed in
accordance with the requirements contained in
this Annex.
2.1.2In the case of vehicles and trailers with heaters
for liquid fuel, it is presumed that these vehicles
comply with the requirements in this Annex.
2.2Position of the Heater
2.2.1Parts of the vehicle body and other components
in the immediate vicinity of the heater must be
protected against excessive heat and the danger
of contamination by fuel or oil.
2.2.2The internal combustion heater must not pose a
fire hazard even when overheated. This
requirement is deemed to have been met if care
is taken during installation to ensure an
adequate distance from all parts, as well as
adequate ventilation and if fire-resistant
materials or heat shields are used.
2.2.3For passenger carrying vehicles such as shuttle
busses, transit busses, and coaches, the heater
must not be installed in the passenger cabin. A
device in a sealed cover, which also meets the
requirements set out in paragraph 2.2.2, may be
used, however.
2.2.4The model/ Serial plate or a duplicate thereof
(duplicate model/ Serial plate) must be fitted in
such a way that it is still clearly legible when the
heater has been installed in the vehicle.
2.2.5When positioning the heater, all reasonable
precautions must be taken to minimize the risk
of personal injury or damage to items in the
vehicle.
2.2.6A clearly visible indicator within the user's field
of vision must show when the heater is switched
on or off.
2.3Fuel Supply
2.3.1The fuel filler neck must not be located in the
passenger compartment and must have a tightly
fitting cap to prevent any fuel leaks.
2.3.2The type of fuel and the fuel filler neck must be
clearly identified on heaters for liquid fuel, for
which the fuel supply is separate from the fuel
supply for the vehicle.
2.3.3A sign must be affixed to the fuel filler neck
warning that the heater must be switched off
before refuelling. An identical warning must also
be included in the manufacturer's operating
instructions.
2.4Exhaust System
2.4.1The exhaust outlet must be positioned in such a
way that exhaust fumes cannot enter the interior
of the vehicle through ventilation devices, hot-air
inlets or open windows.
2.5Combustion Air Inlet
2.5.1The air for the combustion chamber of the
heater must not be extracted from the
passenger cabin of the vehicle.
2.5.2The air inlet must be positioned in such a way
that it cannot be obstructed by other objects.
2.6Water Inlet
2.6.1The supply of water to be heated must be
protected against freezing with a suitable
antifreeze additive to the required strength as
directed by the manufacturer. The supply of
water to be heated must be uncontaminated by
corrosive compounds and other impurities.
2.6.2The inlet hose must be protected from damage.
2.7Hot Water Outlet
2.7.1Hot water hoses within the vehicle must be
positioned or protected in such a way as to
exclude all risk of injury or damage caused by
direct contact.
Thermo Pro 90Regulation for Installation in the Vehicle
2.7.2The water outlet hose must be protected so that
it cannot be obstructed by other objects or the
flow of water through the hoses.
IMPORTANT!
Failure to follow the installation
instructions and the notes contained
therein will lead to all liability being
refused by Webasto. The same applies if
repairs are carried out incorrectly or with
the use of parts other than genuine
Webasto service parts. This will result in
the invalidation of the type approval for
the heater and therefore of its
homologation / type licence.
www.webasto.us7Webasto Thermo & Comfort N.A., Inc.
Page 7
Purpose / VersionThermo Pro 90
3.Purpose / Version
3.1Purpose of the Coolant Heater
The Webasto Thermo Pro 90 coolant heaters are used in
connection with the vehicle’s own heating system
– to heat the cab,
– to defrost vehicle windows and
– to preheat water-cooled engines,
– to heat boats and motor-homes (recreational vehicles)
The water heater operates independently of the engine
and is connected to the cooling system, the fuel system
and the electrical system of the vehicle.
The Thermo Pro 90 heaters differ from each other in their
component connection arrangement and in the fact that
they have different control units.
3.2Versions
3.2.1Thermo Pro 90 version
Thermo Pro 90 12V / 24V diesel
Water heater for “diesel” fuel
The water heaters are designed for 12 V and 24 volts.
The water heater must be installed outside
the passenger cabin.
The requirements of the latest version of
“Hazmat” must also be observed for the
installation of the heater into vehicles used
to transport hazardous substances.
4.1Installation site / Installation position
The heater must be installed in as low a position as
possible to allow the heater and circulating pump to be
bled automatically. This is particularly important as the
circulating pump is not self-priming.
The installation must be performed in accordance with
the installation instructions provided in this manual.
NOTE:
If the vehicle manufacturer has issued specific installation
instructions, they must be followed.
4.2To install the heater
The heater must be secured with at least three M8
screws. The screws must be tightened with a torque of
18 Nm. (13.3 lb-ft).
exhaust temperature sensor and the loose routing of the
exhaust temperature sensor cable to the control unit
must be ensured during installation.
4.3Model plate
The model plate must be positioned so that it cannot be
damaged and must be clearly legible when the heater is
installed (otherwise a duplicate model plate must be
used).
Inapplicable years must be erased from the model plate.
4.4CE mark
The Thermo Pro water heater carries the CE mark since it
complies with the regulations in force. The heater
satisfies the requirements of class A. As a result, the
following supplement applies:
This is a class A device. This device
may induce radio interference in
residential areas; in this case, the
owner may be required to
undertake appropriate measures.
As a rule, installation in the engine compartment
represents sufficient screening. Please contact the
Webasto technical support team in the event that radio
interference occurs nevertheless.
4.2.1Exhaust Temperature Sensor
The exhaust-temperature sensor cable is designed for
high temperature (heat - resistant). The material is
resistant to continuous effects of temperatures of up to
185 °C, however it is sensitive to external mechanical
influences. Before the final installation location has been
set, it is recommended conduct an analysis for the
possible risk of damage to the cable due to stone impact.
If stone impact is possible then precautionary measures
must be taken. e.g. protective covering.
The exhaust temperature sensor must be handled
carefully - it is a sensitive electronic ceramic component!
Tensile loading of the exhaust temperature sensor cable
on the sensor head must always be avoided during
installation and heater operation. Sharp bends in the
cable at the sensor head are not permitted in order to
prevent damage to the Teflon insulation of the cable.
Do not pull on the cable after the exhaust temperature
sensor is installed!
Should a sensor be dropped during maintenance work,
then a new sensor must be installed.
The proper condition of the mica disc (insulation) on the
sensor, the force-free seating of the cable clips of the
4.5Compatibility
The heater is reverse compatibly with previous models
regarding installation points on the vehicle.
The peripherals of the Thermo Pro 90 are also compatible
with the previous model Thermo 90 ST. This makes it
possible to retrofit a Thermo Pro 90.
When the Thermo 90 ST is replaced with a Thermo Pro
90, the metering pump of the Thermo 90 ST (DP2 or
DP30) must also be replaced with the Thermo Pro 90
metering pump (DP42)!
When the metering pump is replaced (from DP2 or DP30
to DP42), a new metering pump wiring harness must be
used for connecting the DP42 to the existing Thermo 90
ST wiring harness (5m metering pump harness 5010871A).
www.webasto.us9Webasto Thermo & Comfort N.A., Inc.
Figure 7: Optional perpendicular mounting with bracket kit P/N 905838
www.webasto.us13Webasto Thermo & Comfort N.A., Inc.
Page 13
Connection to the Vehicle Cooling SystemThermo Pro 90
Optimum Cross-Flow Through Engine
7.Connection to the Vehicle Cooling System
7.1General Information
The heater is connected to the vehicle cooling system as shown in Figures 9 through 14, depending on the type of
heating system the vehicle is equipped with. The system must contain at least 6 litres (1.6 US Gal.) of coolant. The
system must be filled with an antifreeze and water mixture as recommended by the vehicle manufacturer. Coolant flow
throughout the system must be maintained in all operating conditions.
If desired, shut-off valves can be installed at the engine inlet and outlet connections of the coolant heater circuit,
although, shut-off valves are not mandatory. All valves should remain open throughout the year.
IMPORTANT!
To maintain optimum heater condition, periodically run heater for 20 minutes monthly during the
off-season. Ensure any shut-off valves are open before operating the coolant heater.
• Use 1/2” or larger NPT pipe fittings for hose connections at engine.
• Use good quality, heavy duty 3/4” ID. coolant hose for the coolant heater circuit.
• Hoses must be installed without kinks and bends which may restrict coolant flow.
• To ensure proper bleeding of air, keep hoses rising if possible. Avoid “goose necks” to prevent trapping air.
• Hoses must be supported where required to prevent chaffing and damage from vehicle components.
• Hose connections must be secured by hose clamps to prevent them from slipping off.
• Coolant heater flow direction should match the flow direction of the engine’s coolant circulation system.
IMPORTANT!
The hose clamps must be tightened with a torque of 4 Nm. (35 lb.-in.)
The use of silicone hose requires special hose clamps.
Separate the heater supply and return
connections at the engine as far apart as
is practical for optimum engine heating
and heater performance. See Figure 8.
Thermo Pro 90Connection to the Vehicle Cooling System
1
2
3
4
5
6
7
1. Coolant supply connection
2. Vehicle heat exchanger
3. Coolant pump
4. Thermo Pro 90 heater
5. Coolant return connection
6. Engine coolant pump
7. Thermostat
1
22
3
4
5
6
7
1. Coolant supply connection
2. Vehicle heat exchangers
3. Coolant pump
4. Thermo Pro 90 heater
5. Coolant return connection
6. Engine coolant pump
7. Thermostat
The cooling system must be bled carefully before using the heater for the first time or after replacing the coolant.
Proper venting of trapped air can be identified by the circulating pump operating almost silently. Poor bleeding may
cause the resetting temperature limiter to trip while the heater is in operation.
7.2Various Plumbing Configurations
Select the appropriate plumbing configuration according to the customers requirements and the vehicle system type.
Figure 9 illustrates an engine preheat / boost heat configuration.
Figures 10 through 13 illustrate configurations for bunk heat and engine preheat / boost heat.
Figure 14 illustrates a system for vehicles with continuous fan operation or high amperage heat exchanger fan designs.
In this case, the addition of a low amperage draw, auxiliary heat exchanger system is recommended.
Figure 9: System configured for engine pre-heating and boost heating.
Figure 10: System configured in a “series” fashion with both heat exchangers.
www.webasto.us15Webasto Thermo & Comfort N.A., Inc.
Page 15
Connection to the Vehicle Cooling SystemThermo Pro 90
1
22
3
4
5
6
7
1. Coolant supply connection
2. Vehicle heat exchangers
3. Coolant pump
4. Thermo Pro 90 heater
5. Coolant return connection
6. Engine coolant pump
7. Thermostat
1
22
3
4
5
6
7
1. Coolant supply connection
2. Vehicle heat exchangers
3. Coolant pump
4. Thermo Pro 90 heater
5. Coolant return connection
6. Engine coolant pump
7. Thermostat
4-way back-check valve
1
22
3
4
5
6
7
8
9
9
10
1. Coolant supply connection
2. Vehicle heat exchangers
3. Coolant pump
4. Thermo Pro 90 heater
5. Coolant return connection
6. Engine coolant pump
7. Thermostat
8. Automated control valve
9. Wye connectors
10. Bypass hose 13-16mm I.D.
(1/2”- 5/8” I.D.)
Figure 11: System configured in series with rear heat exchanger in a “dual” circuit heating system.
Figure 12: System configured in the rear heat exchanger circuit using an optional 4-way back-check valve.
Figure 13: System configured with a bypass circuit within the rear heat exchanger circuit where an automated flow
control valve is installed. Bypass is required in the event the valve is closed during heater operation.
Thermo Pro 90Connection to the Vehicle Cooling System
1
22
3
4
5
6
7
8
11
9
9
1. Coolant supply connection
2. Vehicle heat exchangers
3. Coolant pump
4. Thermo Pro 90 heater
5. Coolant return connection
6. Engine coolant pump
7. Thermostat
8. Automated control valve
9. Wye connectors
10. N/A
11. Auxiliary heat exchanger
Figure 14: System configured with an additional auxiliary heat exchanger connected in “series / parallel” with rear heat
exchanger circuit.
www.webasto.us17Webasto Thermo & Comfort N.A., Inc.
Page 17
Fuel SupplyThermo Pro 90
0
°
A
B
C
D
E
F
G
A. Fuel standpipe
B. Connector hose
C. Fuel filter
D. Hose clamp
E. Fuel pump
F. Fuel line
G. 90° Connector hose
8.Fuel Supply
8.1General Information
The values for the maximum pressure at the fuel
extraction point are shown in the table below and in
Figure 16.
Intake SidePressure Side
D1- Inside diameter of fuel line
= 2 mm.
H1 - Dimension for fuel tank
over metering pump [m]
S1 - Dimension for fuel tank
under metering pump [m]
l1 - Length of fuel line
with D1 = 2 mm => l1 ≤ 3 m
P1: Relative fuel pressure at
removal point
D2: Inside diameter of
fuel line = 2 mm.
H2: Dimension for heater
over metering pump [m]
S2: Dimension for heater
under metering pump
[m]
l2: Length of fuel line
The fuel is taken from the vehicle fuel tank or from a
separate fuel tank. The exploded view in Figure 15
Illustrates the progression of fuel system components.
A sign must be affixed to the fuel tank’s filler neck
warning that the heater must be switched off before
refuelling.
This separate fuel pickup precludes any effect of
pressure.
Where available, a spare NPT threaded port can be
utilized for the standpipe. If a spare port is not present,
proceed with the following instructions under “To install
the standpipe”.
1. bore a 25mm (1”) hole through top of fuel tank
(item G, Figure 17).
2. remove sharp burrs and smooth edges with emery
cloth.
3. determine length of standpipe when installed. End
should sit at least 25mm (1”) above tank bottom.
Cut off excess standpipe at a 45 degree angle.
Remove burrs.
4. loosely assemble items C, D, E, and F (Figure 17).
5. place sealing compound on threads of item B and
thread into item F. Tighten item B completely.
6. slide standpipe into hole at angle. Slip one shoulder
of item F, Figure 17 inside the hole as shown in
Figure 18.
Figure 17: Webasto fuel standpipe
www.webasto.us19Webasto Thermo & Comfort N.A., Inc.
Only steel and plastic lines made of plasticized, light and
temperature-stabilized may be used for the fuel lines.
Since the lines normally cannot be routed with a constant
rising gradient, the internal diameter must not be
allowed to exceed a certain size. Air or gas bubbles will
accumulate in lines with an internal diameter of more
than 4 mm (5/32 in.) and these will cause malfunctions
whilst the heater is operating if the lines sag or are
routed downwards. The diameters specified in Figure 16
will ensure that bubbles do not form.
The lines should not be routed downwards from the
metering pump to the heater.
Unsupported fuel lines must be secured to prevent them
from sagging. They must be installed in such a way that
they cannot be damaged by flying road debris and high
temperatures, i.e. close to the exhaust line.
The fuel lines must be secure at the connections using
hose clips to prevent their slipping.
Figure 23: Fuel line / coupler hose connection
8.4Fuel Metering Pump
IMPORTANT!
Cut lines without burr and do not crush
them. Do not cut fuel line with side cutting
pliers!
8.3.1Connecting two fuel lines with a
coupler hose
The correct procedure for connecting fuel lines with
hosing is shown in Figure 22. Ensure that there are no
leaks.
The fuel metering pump is a combined delivery, metering
and shut-off system and is subject to certain installation
criteria (see Figures 24).
Figure 24: Metering pump DP42 - installation position
8.4.1Installation Location
It is advisable to install the metering pump in a cool
place.
The metering pump and fuel lines must not be installed
within range of the radiated heat from hot vehicle parts.
A heat shield must be used if necessary.
Figure 22: Fuel line / coupler hose connection
www.webasto.us21Webasto Thermo & Comfort N.A., Inc.
Page 21
Fuel SupplyThermo Pro 90
A
Ø 5mm
0° - 90°
8.4.2Attachment
The metering pump must be secured with a vibrationdamping mounting. Its installation position is limited as
shown in Figure 24 in order to ensure effective automatic
bleeding.
As a result of the risk of corrosion, only genuine Webasto
parts may be used for the plug connections between the
metering pump and the metering pump wiring harness.
8.5Fuel Filter
Only a Webasto filter is allowed to be used if the fuel is
expected to be contaminated. Install vertically if possible,
however at least horizontally (check flow direction).
IMPORTANT!
Do not substitute the Webasto supplied
fuel filter with a non Webasto replacement.
Irregular heater operation may result.
Under no circumstances may the combustion air be
taken from areas occupied by people. The combustion air
intake opening must not point in the direction of travel.
It must be located in that it cannot become clogged with
dirt or snow and cannot suck in splashing water.
IMPORTANT!
The combustion air must be extracted using
a combustion air tube from a position that
is as cool as possible and protected from
splashing water.
The combustion air intake tube (internal diameter at least
30 mm) may be 0.5 m to 5 m (1.6 ft to 16 ft) long with
several bends totalling 360°. The minimum bending
radius is 45 mm (1.75 inches).
The combustion air intake must not be routed in the
vicinity of the exhaust discharge.
IMPORTANT!
A minimum of 0.5m of the combustion air
tube must be installed on every
application.
IMPORTANT!
If the combustion air intake tube cannot be
installed so that it slopes downwards, a
water drain hole with a diameter of 4 mm
(5/32”) is to be made at its lowest point.
If the heater is installed in the vicinity of a fuel source, the
combustion air tube must be routed in a way to prevent
fumes from entering. The openings must be splashproof.
A ventilation opening measuring at least 7 cm² is
required if the heater is installed in an enclosed box. The
size of the ventilation opening must be increased
accordingly if the temperature in the box exceeds the
permitted ambient temperature of the heater (see
Technical data).
www.webasto.us23Webasto Thermo & Comfort N.A., Inc.
Page 23
Exhaust SystemThermo Pro 90
Heater removed for
clarity of illustration
AA
B
C
10. Exhaust System
The exhaust pipe (internal diameter 38 mm) can be installed with a length of 0.5 m to 5 m (1.6 ft to 16 ft) and several
bends totalling a maximum of 360° altogether. The minimum bending radius is 85 mm (3.35 inches).
The exhaust muffler is required
The opening of the exhaust pipe must not point towards the front of the vehicle (see Figure 27).
The exhaust pipe opening must be located so that it cannot become clogged with snow and mud.
Rigid pipes of unalloyed or alloyed steel with a minimum wall thickness of 1.0 mm or flexible piping of alloyed steel
only must be used as exhaust tube. The exhaust pipe is secured to the muffler using an approved muffler clamp. See
Figure 27 for details. See the regulations section 2 for other requirements.
and must be installed near the heater.
Figure 26: Exhaust muffler installation - enclosure kit only
A. Muffler
B. coupler (between heater and muffler)
C. “L” bracket
The exhaust muffler is secured to the heater using a coupler between the heater and muffler and a bracket fastened to
the underside of the enclosure. See Figure 26 for details.
The exhaust pipe must be securely attached
no further than 150 mm (6 in.) from the end
of the exhaust pipe to ensure that the angle
of 90° ± 10° vertical-down is maintained.
Discharge direction almost vertical 90° ± 10°
Figure 27: Exhaust pipe termination
IMPORTANT!
If the exhaust tube cannot be installed so that it slopes downwards at all points, a condensation drain hole
with a diameter of 4 mm (5/32”) is to be made at its lowest point to allow condensate to drain.
www.webasto.us25Webasto Thermo & Comfort N.A., Inc.
Page 25
Electrical ConnectionsThermo Pro 90
1
2
3
4
Main Fuse
1. Switch / Timer Harness
2. Heater Harness (Pre-installed)
3. Main Harness Connector
4. Power Supply Harness
11. Electrical Connections
11.1 Power / Control Harness Connections
Ideally, the heater power supply should be directly from the vehicle’s batteries or main buss-bar.
The heater control unit is equipped with low voltage protection. It is imperative that the vehicle batteries be kept in
good condition for optimal heater operation.
For sleeper and engine heating applications, Webasto recommends a four battery system for best results.
A weather sealed fuse holder is to be fitted to protect the heater (supplied with the power / control
harness).
+
–
–
Frame Ground
Figure 28: Power and control harness assembly
A. Route item 1 into the vehicle cab in the area where the switch or timer is to be installed.
B. Route item 4 to vehicle battery box and connect to batteries as shown in Figure 28. Brown wire to ground, red wire with fuse
holder to positive. Ensure battery connections are clean and protected with an anti-corrosive compound.
C. Item 3 (main connector) should be left unconnected until all electrical components are installed and heater is ready for the
initial start-up.
IMPORTANT! All power connections must be fused within 14” of the battery.
Figure 34: Thermo Pro 90 with 7-day SmarTemp Control fx Timer - Connection Diagram
www.webasto.us33Webasto Thermo & Comfort N.A., Inc.
Page 33
Initial Start-upThermo Pro 90
13. Initial Start-up
IMPORTANT!
Refer to the safety instructions in the operating and maintenance instructions.
The operating and maintenance instructions must be read thoroughly before starting the heater.
HEATER MOUNTINGComplete
(Yes/No/Comments)
1Is the heater installation safely secure / rigid?
(Ensure that all bracket bolts are tight)
2
Is there a safe clearance from heat generating
Components? (I.e. exhaust, etc...)
3Is there sufficient clearance between heater and any
vehicle moving components under all operating
conditions? (steering cranked to extreme positions,
torqued engine, suspension, etc...)
4Is the heater mounted in an acceptable position
according to the limitations noted in the
installation manual?
5Is the heater installed in a protected location from
road debris and splash-water or items stored in the same area?
6Is there a sufficient amount clearance
between the heater and the ground? (Coolant heaters only)
COOLANT SYSTEMComplete (Yes/No/
Comments)
1Is there a safe clearance (min 4 in.) from heat generating components?
(exhaust, etc...)
2Is there a safe clearance from sharp edges / objects?
Ensure a heat protective has been installed (if applicable)
3Are there any kinks, sharp bends or the possibility for pinched hoses or
harnesses, cuts and rub through?
4Have all the hose clamps been properly positioned and tightened?
5
Has the coolant system been topped off and bleed per the vehicle
manufacture’s specifications for proper mixture and type?
6Has a pressure test been performed on the coolant system under all
operating conditions?
7Have the coolant hoses been installed so that they are below the coolant
Has all wiring been safely secured away from moving components
and / or heat sources?
2
Check for proper power and ground connections.
3
Has blower motor functionality been tested (if applicable)?
4
Check for proper fuse tap connection.
5
Verify the correct fuses are in the specified locations per the
installation manual.
6
Ensure heater and vehicle fuse boxes are closed and secure. Was the
Webasto fuse block installed in a location protected from water and /
or moisture?
7
Ensure blower motor resistor (1.0Ω) is securely mounted and has
sufficient clearance from any plastic component and battery.
8
Ensure battery is mounted securely and connections are properly
tightened.
9
Ensure battery is at ≥ 12.2Vdc.
FUEL SYSTEMComplete (Yes/No/
Comments)
1
Is the standpipe properly mounted in the fuel tank?
(sealed, structural integrity maintained).
2
Validate the standpipe does not interfere with function of sending
unit by checking fuel gauge for proper operation before completing
installation of tank.
3
Verify that all fuel lines are properly secured and are a safe distance
(min. 4 in.) from exhaust systems and / or moving components.
4
Check all fuel lines for leaks or kinks.
5
Check fuel line clamps for proper positioning and tightness. Ensure
fuel system is free of leaks.
6
Ensure fuel pump is securely mounted in a cool location
NOTE: Vehicle fuel tank area is generally a location with minimal
sound transfer path to vehicle interior.
EXHAUST SYSTEMSComplete
(Yes/No/Comments)
1
Is the muffler and clamps securely tightened?
2
Has muffler and exhaust tube been routed a safe distance (min. 2 in.)
from flammable material?
3
Ensure drain-holes are drilled in low bend areas of exhaust tube.
4
Ensure exhaust is venting a safe distance from any vehicle interior
openings.
5
Ensure exhaust is venting in the direction that will not cause back
pressure while driving.
www.webasto.us35Webasto Thermo & Comfort N.A., Inc.
Page 35
Initial Start-upThermo Pro 90
DANGER
COMBUSTION AIR INTAKEComplete
(Yes/No/Comments)
1
Is the combustion air intake drawing fresh air from a non-turbulent
location? (i.e. not in direction of travel)
2
Ensure air intake system is securely fastened.
HEATER FUNCTIONComplete (Yes/No/
Comments)
1
Ensure heater starts and runs for a minimum of 20 minutes.
2
Ensure vehicle blower turns “ON”.
3
Ensure warm air is blown out of interior vents after blower is
activated.
4
Ensure timer (control device) is functioning.
5Check and Modify CO2 setting as needed based on altitude (will the
heater “live” or spend a lot of time above XXXXXX Feet)
(See service manual for instructions to make adjustment)
COSMETICSComplete (Yes/No/
Comments)
1
Has the vehicle interior, engine compartment, trunk & glove
compartment been inspected for cleanliness after installation.
2
Has user manual placed in glove box?
3
Is the vehicle clock time correct after disconnecting the battery?
If you have any questions, contact our technical support team at (800) 860-7866 or via email at:
info-us@webasto.com
.
HEATER MUST
AND/OR WHILE LOADING OR UNLOADING FLAMMABLE MATERIALS FOR
TRANSPORT, TO PREVENT THE RISK OF EXPLOSION. PLEASE REVIEW OWNER’S
MANUAL FOR SAFETY AND USE INSTRUCTIONS.
BE SWITCHED “OFF” WHEN REFUELING AT FILLING STATIONS
The control unit continuously monitors the heater operation. The control unit identifies errors on individual heater
components and faults during operation. Should the control unit experience component errors and operational faults,
the heater will be shut down.
14.2 Heater Interlock
Fuel is supplied for a max. of 240 seconds if the flame does not start.
Fuel is supplied for a max. of 240 seconds if the flame goes out during operation.
The fuel supply is shut off if the system overheats (temperature limiter is tripped). If the system overheats the
temperature limiter will reset itself after a cool down period.
If the under-voltage protection switches the system off for longer than 20 seconds, the fuel supply is interrupted and
the heater switches OFF.
NOTE:
The heater does not automatically switch back ON. The heater will need to be switched OFF and back ON to re-start
after a fault.
Thermo Pro 90
12 Volt10.V – 0.5V
24 Volt21V – 1V
14.2.1 Heater Lock out Reset Procedure
Heater Lock out Reset Procedure
1. Using switch or standard timer control, turn heater on
2. Remove the main power connection to heater from battery or pull fuse for a minimum of 20 seconds.
3. Using switch or standard timer control, turn the heater off.
4. Reinstall main heater power connection where previously disconnected.
Rectify the cause of the fault.
IMPORTANT: Heater fault codes can be read using PC Diagnostics, however, the heater lockout reset must be
manually performed using the procedure stated above.
:
14.3 Diagnostic after a Fault Lock-out for the Thermo Pro 90
Check the fuses and plug connectors.
14.3.1 Version with switch
If the system is operated with a switch, the nature of the fault is indicated by a flashing code on an indicator light
(toggle of switch) during the run-on time of the heater.
After five short signals, count the long flashes:
1xNo start (after 2 attempts to start)
2xFlame failure
3xUnder-voltage or over-voltage
www.webasto.us37Webasto Thermo & Comfort N.A., Inc.
Page 37
TroubleshootingThermo Pro 90
4xPremature flame recognition
5xN/A
6xCoolant temperature sensor interrupt or temperature sensor short-circuit
7xMetering pump interrupt or metering pump short-circuit
8xBlower motor interrupt or blower motor short-circuit or blower motor incorrect speed
9xGlow plug interrupt or igniter short-circuit
10x Overheating
11x Circulating pump interrupt or circulating pump short-circuit
12x Battery main switch short circuit
13x Output vehicle fan short circuit
14x Overheating protection defective
15x Reference resistance not reached during start
16x Exhaust gas temperature too high
17x Exhaust temperature sensor defective
14.3.2 Version with timer
If the system is equipped with a digital timer, a fault message appears on the display of the timer after a fault occurs:
F 01No start (after 2 attempts to start)
F 02Flame failure
F 03Under-voltage or over-voltage
F 04Premature flame recognition
F05 N/A
F 06Coolant temperature sensor interrupt or temperature sensor short-circuit
F 07Metering pump interrupt or metering pump short-circuit
F 08Blower motor interrupt or blower motor short-circuit or blower motor incorrect speed
F 09Glow plug interrupt or igniter short-circuit
F10 Overheating
F 11Circulating pump interrupt or circulating pump short-circuit
Except where limit values are specified, the technical data refer to the usual heater tolerances of ±10% at an ambient
temperature of +20 °C (68 °F) and at the nominal voltage and conditions.
15.1 Electrical Components:
The control module, motors for combustion air blower and circulating pump, ceramic glow pin, metering pump, switch
and timer are available in 12 and 24 volt versions.
The temperature limiter, temperature sensor and flame sensor are identical on 12V and 24V heaters.
15.2 Fuel for Thermo Pro 90 (Diesel):
The diesel fuel specified by the vehicle manufacturer must be used. Heating oil may also be used as long as it complies
to the normal quality available on the North American market.
We know of no negative influences due to additives.
If fuel is extracted from the vehicle’s tank, follow the additive instructions issued by the vehicle manufacturer.
If you change to low-temperature fuel, the heater must be operated for approximately 15 minutes so that the fuel
system is filled with the new fuel.
The Thermo Pro 90 heater is also approved for use with PME (bio-diesel), which complies with DIN EN 14214.
HeaterOperationThermo Pro 90
Approval symbolE1 122R 00 0320 (Heater)
ModelWater heater with evaporative-type burner
Heat outputMax.
FuelDiesel
Fuel consumptionMax.
Rated voltage12 V24 V
Operating voltage range10.5... 15.5 Vor 20 ... 31.5 V
Nominal power consumption with circulation
pump (without vehicle fan)
Perm. ambient temp.:
Heater control Unit:- Operation
-Storage
Metering pump:- Operation
-Storage
Perm. operating pressure (heat medium)Max.2.0 bar (29 PSI)
Capacity of the heat exchanger0.15 l (.158 quart)
Max. combustion air intake temperature+40 °C (104°F)
Minimum capacity of the system6.00 l (6.34 quarts)
CO2 in the exhaust gases (normal function range) Max.9 ... 11.5% by volume
Heater dimensions (tolerance 3 mm)
* Control module installed on the heater