FNM HPEP 225 Installation Manual page 28

Hot Water Heater Installation Recommendation
IMPORTANT: When connecting a cabin heater or hot water heater, certain
requirements must be met, including but not limited to the following:
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Avoid a performance loss and/or possible engine damage. Engine coolant
must flow continuously from the engine intake manifold to the engine water
circulating pump. NEVER close-off or block the coolant flow to or from a
heater. All heater installations must be plumbed in series with the supply and
return connectors.
Avoid engine overheating which could result in engine damage. On models
equipped with Closed Cooling, an air pocket may form in the closed cooling system
if some coolant is lost from the system and the cabin heater or hot water is mounted
higher than the fill cap on the heat exchanger. Heater must be mounted higher than
the heat exchanger on models so equipped.
WATER FLOW
Water flow must be from engine supply hose connection to inlet of hot water heater. The
water returns from outlet on heater to return hose connection on engine.
Supply hose (from engine to heater) and return hose (from heater to engine)
MUST NOT EXCEED 5/8 in. (16 mm) I.D. (inside diameter).
Make heater connections ONLY at locations indicated in the following
information.
Refer to manufacturers' instructions for complete installation information and
procedures.
Do not reposition engine temperature switch; it must remain as installed by
factory.
Typical flow diagram
CAUTION
CAUTION
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