INSTALLING THE HEATER
PREPARE COOLANT SYSTEM
1. Drain and ush cooling system to remove any debris
present in the engine’s cooling system.
SELECT PORTS
2. Select return port. The return port will allow heated
coolant to return to the engine. See Fig 2 on following
page. The return port should be located:
• away from the engine thermostat
• toward the rear (ywheel) of the engine
• away from the supply port
• on the same side of the engine as the intended
heater mounting location
3. Select supply port. The supply port will allow coolant
to ow from the engine to the heater. See Fig 2 on
following page. The supply port should be located:
• toward the front (radiator) of the engine
• at the lowest point of the engine’s water jacket
• away from the return port
NOTE: For V-type engines, it is acceptable to
select a supply port on the opposite side
of the engine as long as the supply hose is
routed properly. See PLUMB HEATER.
SELECT HOSE, FITTINGS & VALVES
4. Select ttings. CSM minimum port size tting:
• 20 mm (3/4 inch NPT)
5. Select hoses. CSM minimum hose inner diameter:
• 25 mm (1 inch)
NOTE: Select hoses rated for 121 °C (250 °F) and
690 kPa (100 psi) minimum.
6. Select optional, user-supplied isolation valves.
NOTE: Hotstart recommends installing valves to
isolate the heating system in case of service.
To minimize ow restriction, select full-ow
(full-port) ball isolation valves.
MOUNT HEATER
NOTICE
Vibration damage: Do not mount
heater directly to engine. Engine
vibration will damage heater. If the
heater is installed with rigid pipe,
connect exible hose to inlet and
outlet to isolate from vibration.
Heater orientation: CSM units must be installed with
discharge port pointing directly upward. See Fig 2 on
following page. Do not mount at an angle. An incorrectly
oriented heater may cause heater failure.
7. Select a heater mounting position. The heater should
be located:
• low enough to allow the return hose to continuously
rise to the return port
• on the same side of the engine as the return port
• in a position to ensure the discharge port points
directly upward
• in a location that allows a minimum of 43 cm
(17 inches) clearance for heating element removal
PLUMB HEATER
NOTICE
High points: Do not allow high
points along heater plumbing.
High points will restrict coolant
ow and damage heater. To avoid
high points, it may be necessary
to change hose routing or lower
heater mounting location.
Dips and bends: Do not allow dips
or bends along heater plumbing.
Dips or bends will allow air pockets
to form, restricting coolant ow
and damaging heater.
90° Fittings: Elbows (90° ttings) along heater plumbing
may restrict ow and damage heater. To minimize ow
restriction, Hotstart recommends sweeping bends or 45°
ttings in place of 90° ttings.
8. Install isolation valves to port ttings.
9. Route and install return hose. The return hose should
continuously rise from the heater to the return port.
10. Route and install supply hose. The supply hose
should continuously descend from the supply port
to the heater.
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installation instructions
Hotow®csm Heater
