T
HERMO
90 / 90 S
8SERVICING
8-3
8.6 Visual Inspections and Installation
Regulations
8.6.1 Connection to the Vehicle's Cooling
System
In thermostat circuits only thermostats opening at
< 65 °C (149 °F) are to be used.
The installation of the heater should be in a location as
low as possible to ensure static priming of the heater and
circulation pump. This applies in particular for the
circulation pump, which is not self-priming.
The heater is to be connected to the cooling system
according to Fig. 8-1. The amount of coolant in the
cooling system must be at least 6 litres (1.6 US gal.).
The coolant hoses used must meet the minimum
requirements of DIN 73411. The hoses must be routed
without kinking, and for proper priming where possible, in
an upwards direction.
Hose connections must be secured with hose clamps to
prevent slippage.
NOTE:
Hose clamps must be torqued to 1.5 Nm (clamps
previously in use) or to 5.0 Nm (new, wide clamps).
Prior to first operation of the heater or after replacement
of the coolant, bleed the cooling circuit.
Heater and lines have to be installed so that a static
priming is guaranteed.
Insufficient priming during heating operation may cause
failure due to overheating.
Proper priming is indicated by a circulation pump almost
noiseless in operation. Insufficient priming during
heating operation may cause the resettable temperature
limiter to trip.
8.6.2 Connection to the Vehicle's Fuel System
Fuel is tapped from the fuel reservoir of the vehicle or
from a separate fuel container.
Fuel lines must be of the type as described in section
8.6.2.2 of this manual.
The fuel system limitations are illustrated in Fig. 8-2.
Maximum suction height (A) = 1 m (3’ 3”)
Maximum suction length (A + B) = 2 m (6’ 6”)
Maximum delivery length (C + D) = 6 m (19’ 6”)
Maximum delivery height (D) = 3 m (9’ 9”)
Previous New
Fig. 8-2 Fuel Supply
