Connection To The Vehicle Cooling System; General Information - Webasto Thermo 90 ST B Installation Manual

Connection to the Vehicle Cooling System

7. Connection to the Vehicle Cooling System

7.1 General Information

The heater is connected to the vehicle cooling system as shown in Figures 10 through 15, 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 ten or more 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.
Optimum Cross-Flow Through Engine
Figure 9: Ensure optimum cross-flow
Webasto Product N.A., Inc.
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 9.
12
Thermo 90 ST
www.techwebasto.com