Webasto Thermo 90 ST User manual

– 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.
– Installation and repair of Webasto heating and cooling systems requires special
Webasto training, technical information, special tools and special equipment.
– NEVER attempt to install or repair a Webasto heating or cooling system unless you
have successfully completed the factory training course and have the technical skills,
technical information, tools and equipment required to properly complete the
necessary procedures.
– ALWAYS carefully follow Webasto installation and repair instructions and heed all
WARNINGS.
– Webasto rejects any liability for problems and damage caused by the system being
installed by untrained personnel.
CAUTION
Webasto BlueCool Premium
Thermo 90 ST - Chiller
Installation Manual

Table of Contents
www.webasto.us Webasto Product N.A., Inc. www.techwebasto.com
3
Contents Page
Foreword 4
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Scope and Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Safety and Important Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Symbol Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Heater Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Packaged Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Installation 8
General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Installation Site / Installation Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Hose Connections to Chiller Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Fuel Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Combustion Air Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Heater Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Electrical System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Information about Air Guidance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Circuit Diagrams 21
Initial Start-up 23
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Description and Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Technical Data 24
Troubleshooting 25
Fault lock-out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Version with Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Foreword
www.webasto.us Webasto Product N.A., Inc. www.techwebasto.com
4
1. Foreword
General
Webasto Product North America, Inc. is pleased to provide this installation manual with the Thermo 90 ST designed for the
BlueCool Premium System. When used according to the guidelines stated in this manual, you can expect to provide years
of trouble-free, enjoyable operation for your customer.
We encourage our customers towrite to us with their comments or criticisms concerning this manual or product. Thank you
for your participation.
Please write to us at:
Webasto Product 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 immediate questions concerning this manual, the installation procedures within or the product itself, please call
our technical support team at: [phone] or send a fax to: [phone]
Scope and Purpose
This manual is intended to provide the information necessary to ensure proper installation and operation of the Thermo 90
ST in conjunction with the BlueCool Premium System. Improper installation can result in unsatisfactory performance and/
or premature failure of these units. BEFORE proceeding, please read this manual completely. In the interest of product
improvement, specifications and design are subject to change without prior notice.

Foreword
www.webasto.us Webasto Product N.A., Inc. www.techwebasto.com
5
2. Safety and Important Information
Failure to follow the installation instructions and the notes contained therein will lead to all liability being refused by
Webasto Product. The same applies if repairs are carried out incorrectly or with the use of parts other than genuine spare
parts.
All Webasto BlueCool (WBC) products are 110 or 220 volt components that are only allowed to be installed, connected and
maintained by trained and duly certified personnel. The electrical power supply must be permanently disconnected before
any work is started on the systems.
The year in which the heater is used for the first time must be permanently recorded on the heater’s factory plate by deleting
the inapplicable year figures.
The heater must not be operated:
• In filling stations
• In places where explosive vapors or dust may build up (e.g. near fuel, coal, wood, or dust).
• In enclosed rooms (e.g. winter storage facilities)
The heater must not:
• Be exposed to temperatures of more than 248°F (120 °C) (storage temperature), otherwise the electronics may
suffer permanent damage.
The heater must:
• Be operated with the fuel specified on the factory plate.
• Be switched off if considerable quantities of smoke is generated, in case of unusual combustion noises or if you
smell fuel. Switch it off by removing the fuse. The heater must not be restarted until the unit has been checked by
personnel duly trained by Webasto.
• Be operated for 10 minutes at least once a month. The heater must be inspected by a specialist at the beginning of
the heating season or earlier.

Foreword
www.webasto.us Webasto Product N.A., Inc. www.techwebasto.com
6
Symbol Identification
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.
Heater Dimensions
DANGER
WARNING
CAUTION
OR
381
==
99
89
45
20ø
5ø
39ø
92
152 88
95
30ø 38ø
20ø
352
131
49
99
137 100
1. Combustion Air Intake
2. Exhaust Fume Outlet
3. Fuel Intake
4. Coolant Inlet
5. Coolant Outlet
Fig. 1 Dimensions of the Thermo 90 ST
12
3
5
4

Foreword
www.webasto.us Webasto Product N.A., Inc. www.techwebasto.com
7
Packaged Components
Category Description Qty.
Intake and Exhaust TUBE FLEX SS 38MM X 2M 1
TUBE FLEX PAK 30MM X 2M 1
CLAMP EXHAUST 1 1/2" 4
CLAMP HOSE AIR INTAKE 2
THRU HULL EXHAUST 1
Fuel System FUEL LINE METAL (3/16"DIA) 25 FEET 1
COMPRESSION FITTING 3/16" COUPLING UNION 1
STANDPIPE W/COMPRESSION FITTING 1
COUPLER FUEL LINE STRAIGHT 1
CLAMP HOSE 9.5-10.5MM 2
FUEL PUMP ENCLOSURE 1
Manuals / Warranty ENVELOPE WHITE 9"X12" 1
WARRANTY CARD 1
THERMO 90 ST INSTALLATION MANUAL 1
Heater Parts THERMO 90 ST 12V MARINE HEATER 1
HARNESS POWER / SWITCH 1
INTERNAL HARNESS THERMO 90 S 1
Parts Bag Clamps CLAMP HOSE 13-32MM 1/2" SS MARINE GRADE 6
Parts Bag Mounting BOLT M6 X 25 SS 4
NUT M6-1.0 SS 4

Installation
www.webasto.us Webasto Product N.A., Inc. www.techwebasto.com
8
1. Installation
General Information
IMPORTANT
• The Thermo 90 ST must be installed outside the passenger cabin.
• The following temperature ranges apply to some components:
• ABS pipe system (G. Fischer) and fittings from -40°F - 140°F (-40°C to +60°C). Use a pipe system designed for
temperatures up to 248°F (120 °C), e.g. Hep2O made by Hepworth.
• Radial blower on the heat exchanger (arranged on inlet side) up to 131°F (55 °C)
• For this reason, a Thermo 90 ST with a specialized control unit must be used. The heater has a pre-programmed
nominal temperature of 126°F (52 °C).
• Thermo 90 ST Heater – 12 volt diesel
• Thermo 90 ST Heater – 24 volt diesel
• If the volume of water in the circuit is too small less than 2.5gal. (10 liters), the heating system may shut down
prematurely. To avoid this, a storage tank should be installed ahead of the heater.
• The heater is incorporated into the water circuit of the air conditioning unit by means of an additional, electrical 3-
way valve. Activation is controlled by the TECC card within the Webasto Blue Cool Premium (WBCP) air conditioning
unit.
• The heater is powered by a 12 or 24 volt battery voltage. The heater is activated by the electronic control unit via a
12 or 24 volt signal wire. The Webasto BlueCool Premium Air Conditioning Unit functions with 110 or 220 volts.
• The circulation pump (P1) operates continuously when the system is switched on. This means there is no need for
the circulating pump on the heater. As a result, it is integrated directly at the heater inlet. A cool down cycle is
assured from program version 413 of the TECC card onwards.
• The Thermo 90 ST offers excellent heat capacity to an air handler power up to 31,000 BTU.
• If an external heater is incorporated into a Webasto Blue Cool Premium System with an electrically operated 3-way
valve, function F 04:“Automatic with External Heater” or function F 05 “Heat Cycle Only with External
Heater” must be preset on the Chiller Control and the operating element must be blocked by a code.
• When connecting the heater, it is essential that the correct terminal is selected for the nominal temperature.
NOTE: If the vehicle manufacturer has issued separate instructions, they must be followed.

Installation
www.webasto.us Webasto Product N.A., Inc. www.techwebasto.com
9
Installation 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 auto-
matically. This is particularly important as the circulating pump is not self-priming.
Mounting the Heater
The heater must be secured with at least three M8 screws. The screws must be tightened with a torque value of 13
lb-ft. (18 Nm).
Model 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.
Fig. 2 Correct installation positions for the Thermo 90 ST

Installation
www.webasto.us Webasto Product N.A., Inc. www.techwebasto.com
10
Hose Connections to Chiller Unit
The Thermo 90 ST is intragrated into the Chiller unit water circuit via a electrically actuated 3-way valve assembly.
Components:
1. Stop valve at ship’s side inlet
2. Sea water filter
3. Webasto Blue Cool Premium Unit 110 / 220 volts
5. 3-way valve
6. Intermediate storage tank (optional)
7. Water heater – Thermo 90 ST 126°F (52 °C)
8. Webasto BlueCool Air Handler 110 / 220 volts
10. Expansion tank
P1 Sea water pump – 110 / 220 volts
P2 Circulating pump – 110 / 220 volts
Fig. 3 BlueCool Premium System with a Thermo 90 ST

Installation
www.webasto.us Webasto Product N.A., Inc. www.techwebasto.com
11
Electrically actuated 3-way valve:
Electrically actuated 3-way valves of the relevant sizes are used in chiller systems with up to 36,000 BTU.
The selection is made according to the diameter of the pipe used.
• 3-way valve 5/8" incl. fitting
• 3-way valve 3/4" incl. fitting
• 3-way valve 1" incl. fitting
The hoses must be installed without kinks and (to ensure perfect bleeding) rising if possible. Hose connections must be
supported by hose clips to prevent them slipping.
NOTE: The hose clips must be tightened with a torque value of 35 lb-in. (4 Nm).
The cooling system must be bled carefully before using the heater for the first time or after
replacing the water. The heater and lines should be installed in such a way as to ensure static
bleeding. Perfect ventilation can be identified by the circulating pump operating almost silently.
Poor bleeding may cause the resetting temperature limiter to trip while the heater is operating.
CAUTION
Fig. 4 Electrically Actuated 3-way Valve

Installation
www.webasto.us Webasto Product N.A., Inc. www.techwebasto.com
12
Fuel Supply
The fuel can be used from the vehicle fuel tank or from a separate fuel tank. The values for the maximum pressure at
the fuel extraction point are shown in the table below.
A sign must be affixed to the fuel filler neck warning that the heater must be switched off before refuelling.
Connection to Fuel Source
The fuel can be taken from the vessels fuel tank or a separate tank
NOTE: Ensure to deburr the sharp edges from the standpipe after cutting.
NOTE: Refer to fig. 7. The fitting must be made from metal!
Permissible fuel inflow
height H
At max. pressure (PSI)
in fuel line
0.00’ (0.00m) 2.9 PSI
3.28’ (1.00m) 0.16 PSI
6.56’ (2.00m) 0.44 PSI
Maximum fuel intake
height S (Ft.)
At max. negative pressure
(PSI)
in the fuel tank
0.00 (0.00m) -1.5 PSI
1.64’ (0.50m) -0.88 PSI
3.28’ (1.00m) -0.29 PSI
Fig. 5 Fuel Supply
Sealing ring
Fuel Standpipe
Tank fittings
Fig. 6 Fuel Pickup from the Plastic Tank
Hole pattern
Only use a tank connector if the
fuel tank is made from metal
Fig. 7 Webasto Tank Connector

Installation
www.webasto.us Webasto Product N.A., Inc. www.techwebasto.com
13
Since the lines cannot be routed with a constant rising gradient, the internal diameter must not exceed a certain size. Air or
gas bubbles will accumulate in lines with an internal diameter of more than 4 mm and will cause malfunctions if the lines
sag or are routed downwards. The lines should not be routed downwards from the metering pump to the heater.
Unsupported fuel lines must be secured to prevent them sagging. They must b e ins tall ed in s u ch a way that t hey c a nno t b e
damaged by flying debre and high temperatures (e.g. exhaust line).
Connecting two pipes with a hose
The correct procedure for connecting fuel lines with hosing is
illustrated in Fig. 8
Ensure that there are no leaks.
Installation location
Before installing the metering pump, ensure that the maximum
pressure occurring at the pickup point is less than 3 PSI. It is
advisable to install the metering pump in a cool place. The
maximum ambient temperature must not exceed 104°F (40 °C) at
any time during operation.
The metering pump and fuel lines must not be installed within
range of the radiated heat from hot vessel parts. A heat shield must
be used if necessary.
The pump should ideally be installed near the vessels fuel tank.
Installation and attachment
The metering pump must be secured with the supplied vibration-damping mounting clamp. Its installation position is
limited as shown in Fig. 9 in order to ensure effective auto-bleeding.
Fuel filter
Only a Webasto filter P/N: 50487171A is permitted when a fuel filter is needed. Install vertically if possible. (See Fig.10).
NOTE: Ensure to follow the correct fuel filter direction flow marked on the side of the filter.
Clip
Bubble
Correct
Wrong
Bubble
Fig. 8 Pipe / Hose Connections
WARNING
12 V and 24 V – diesel only
Fig. 9 Metering Pump
0° - 90°
Fig. 10 Fuel Filter

Installation
www.webasto.us Webasto Product N.A., Inc. www.techwebasto.com
14
Combustion Air Supply
Asphyxiation risk! The combustion air required for the heater may only be drawn in from the outside or from
spaces that are not occupied by persons e.g. ventilated foredeck box or ventilated *engine compartment
(Diesel only).
The combustion air intake line (internal diameter at least 1 1/8” (30 mm) may be 1 1/2” (0.5 m) to 16 1/2” (5 m) long with
several bends totalling 360°. The minimum bending radius is 1 3/4” (45 mm). The combustion air intake must not be routed
above the exhaust outlet.
Where combustion air is drawn from an internal source, the combustion air tube should be routed away from the heater
with a downward pitch to prevent condensation or moisture from collecting in the tube.
Where combustion air is drawn from an external source, the end of the combustion air intake tube must be routed with a
goose-neck bend with a downward pitch toward the outlet so any water that may penetrate, can drain out and not into the
heater. A 3/16 in. (5mm) condensation weep hole must be provided at the lowest point between the goose-neck to allow
drainage of any trapped condensation or splash water.
Keep combustion air intake tube opening
clear of obstructions!
To avoid pressure differences between exhaust gas outlet and combustion air inlet, the openings of the through-hull fittings
should be located in an area where equal pressure prevails. Do not point the inlet of the combustion air tube in the direction
of travel when intake air is drawn from an external source.
Secure the intake tube to the heater with the provided hose clamps. Ensure the fuel pump connector harness is in place in
the slot provided in the air intake port before tightening clamp. Secure the tube to the adjacent structures with P-clips or
nylon wire ties.
WARNING
Fig. 11 External Combustion Air Intake with Drain Hole

Installation
www.webasto.us Webasto Product N.A., Inc. www.techwebasto.com
15
Heater Exhaust
Route the flexible exhaust in such a way that the heat cannot affect adjacent heat sensitive materials, plastic piping, electric
cables and sails etc. Make sure to use the glass / silicon protective insulating sleeve supplied in the kit to ensure surrounding
objects are protected.
If additional protection is required, it is recommended to over-sleeve with an additional layer of insulation (available from
your local Webasto marine dealer).
DO NOT connect the heater exhaust into the engine or generator exhaust. Doing so will result in
unacceptable back-pressure levels and may damage the heater or cause operational failure.
DO NOT install a flapper valve (clamshell) over the exhaust outlet as this will cause excessive back
pressure within the exhaust system and heater.
DO NOT cover or block the exhaust outlet while the heater is in operation.
The end of the exhaust pipe must be routed with a goose-neck bend and be pitched downward toward the outlet. Any
splash water that may have penetrated can thus drain back out again and not into the heater. This is a dry exhaust and
not water injected.
The exhaust pipe is to be kept as short as possible. The maximum length of 5 meters (16 1/2’) without muffler or 2 meters
(6 1/2’) with muffler must on no account be exceeded. The total radius of bends should not exceed 270 degrees with a
minimum bend radius of 50mm (2 in.).
The exhaust tube and exhaust components must be securely fastened using approved exhaust tube clamps and P-clips as
supplied with the heater kit.
At the lowermost point of the exhaust pipe, a condensation water drain should be installed in which condensation or excess
water collecting in the exhaust pipe can be drained off at regular intervals. Make sure to fill condensation drain with water
to provide a seal against exhaust gas leakage once drain has been installed.
CAUTION
Fig. 12 Exhaust System Layout

Installation
www.webasto.us Webasto Product N.A., Inc. www.techwebasto.com
16
Avoid asphyxiation! If the exhaust pipe is routed through the inside of the vessel, exhaust gas tube must be as leakproof as
possible:
• use only Webasto approved exhaust clamps and firmly tighten clamps.
• an approved exhaust sealant can be used on the inside of the exhaust tube at all connection points
• use condensation water drain
• if desired, use an optional gas tight exhaust muffler to reduce interior noise
•DONOT fit the skin fitting below the water line.
•DONOT cover the exhaust while the heater is in operation.
• DO fit the skin fitting as high as possible to avoid ingress of water.
• DO make sure exhaust clamps are tight and fit well to avoid gas escape.
• DO make sure that exhaust fumes cannot reach the air intake.
WARNING
CAUTION

Installation
www.webasto.us Webasto Product N.A., Inc. www.techwebasto.com
17
Electrical System
General Information
Electrical connections are to be carried out in accordance with the circuit diagrams contained in this installation manual.
When installing the electrical system make sure that the components are installed in protected, dry areas to prevent
corrosion.
If vessel only has one battery, we recommend a second battery be installed for the operation of the heater. To avoid having
to charge the battery too often, its capacity should not be too small.
If you have highly sensitive electronic components on board, a special electrical interference suppression may become
necessary. In this case, please consult a competent specialist workshop.
When actuating the battery disconnect switch (if equipped), wait until the cool down cycle of the heater has been
completed.
Control Module / Heater Connection
The electrical connection of the heaters is undertaken in accordance with the circuit diagrams in Figures 13, 15, 17, and 18.
Thermo 90 ST Control Module
The control module offers protection type 6K9K if it is installed in the position shown in Fig. 13.
24 V
XXXXXXX_.XXXXX
Fig. 13 Thermo 90 ST Control Module, Arbitrary Installation Position

Installation
www.webasto.us Webasto Product N.A., Inc. www.techwebasto.com
18
TECC Program 412 and Higher with Thermo 90 ST and Electrical 3-Way Valve
Because an external water heater (Thermo 90 ST) is being installed with a BlueCool Chiller Unit, the TECC Card must be
reprogrammed for proper operation. This step must be completed in order for proper operation of the Thermo 90 ST.
DEEP PROGRAMMING MODE:
Numbering below in ** represent reference numbers in Fig 14.
Setting Code 2:
1. Programming Code 2: With unit on, lower temperature set-point to
59° F (15° C).
2. Turn the system off by pressing the <on /off button> - *14*.
3. Simultaneously press the <Snow Flake> and <Sun> buttons - *11*.
4. Now in deep programming mode, hit the <F> button twice. The
number 2will be displayed *15* on the left along with the current
value code to the right *16*. e.g. 2 00
5. To change this value, use the <Snow Flake> or <Sun> buttons to
increase or decrease the value. For c5 confutations, use the
following value:
• Programming at nominal temperature 59°F (15 °C) Code 2
value 00 (C1 and T1 closed in heating mode)
6. To confirm a function change, hit the <F>button once to proceed to the next category and hit the <on / off>
button to confirm.
7. Change is successful when the message “NENO” is displayed.
Setting Code 9:
1. Programming Code 9: With unit on, raise temperature set-point to 84° F (29° C).
2. Turn the system off by pressing the <on /off button> - *14*.
3. Simultaneously press the <Snow Flake> and <Sun> buttons - *11*.
4. Now in deep programming mode, hit the <F> button nine times. The number 9will be displayed *15* on the left
along with the current value code to the right *16*. e.g. 9 03
5. To change this value, use the <Snow Flake> or <Sun> buttons to increase or decrease the value. For c5
confutations, use the following value:
• Programming at nominal temperature 84°F (29 °C) Code 9value 03 (C2 and T1 closed in heating mode)
6. To confirm a function change, hit the <F>button once to proceed to the next category and hit the <on / off>
button to confirm.
7. Change is successful when the message “NENO” is displayed.
Setting the Proper Function:
1. To change the function mode: turn the unit on by pressing the <on / off> button.
2. Hit the <F> button until the Function category is reached. The letter Fwill be displayed *15* on the left along with
the current value code to the right *16*. e.g. F 04
3. To change the value, use the <Snow Flake> or <Sun> buttons to increase or decrease the value. For c5
confutations, F 04 and F05 will be the only recommended and usable selections. Refer to the descriptions
below to determine which value is correct for the end user.
•F 04 = Auto Cycle Switching with External Heat Source (AC Heat, Fuel/Water Heater, etc.) - No Reversed
Cycle Valve.
•F 05 = Heat Cycle Only with External Heat Source Alone.
4. To confirm a function change, hit the <F>button once to proceed to the next category and hit the <on / off>
button to confirm.
5. Change is successful when the message “NENO” is displayed.
For electrical connections between the TECC Card and the Thermo 90 ST, refer to Figures 14, 15, 17, and 18.
Fig. 14 Chiller Control 11
12
16
15
14

Installation
www.webasto.us Webasto Product N.A., Inc. www.techwebasto.com
19
Connections on the TECC Card:
R1 - Connection C1
R1 - Connection R1
R1 - Connection T1
R1 - Connection C2
R1 - Connection R2
R1 - Connection T2
Fig. 15 Chiller Unit TECC Card

Installation
www.webasto.us Webasto Product N.A., Inc. www.techwebasto.com
20
Information about Air Guidance
Inlets and outlets:
In principle, the air guidance in the ship is designed for air conditioning operation. This means the air is extracted at floor
level and blown out at ceiling level. By nature, cool air subsides so this arrangement provides a natural circulation of air.
In heating mode, this circulation is weaker and, theoretically, the air is only circulated by the blower.
Improvement possibilities:
One possible solution involves installing closable air outlets in addition to the aforementioned outlet grilles in the floor area.
To do this, a switch must be integrated at a suitable point in the air guidance hoses of the air handler. It is possible to change
from air conditioning to heating operation by operating the switch manually.
Principle of an Air Guidance Switch:
Important points:
• The distance between the (hot) air outlet and the (circulating) air inlet must be at least 5’ (1.5m). (Danger of air
closed circuit)
• Consider the installation complexity (price)
• The customer must perform the changeover manually.
• Currently unavailable as a single part
Fig. 16 Air Guidance Switch