Marquis 420 Sport Coupe Owner's Manual page 60

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Pressurizing and Priming the Water System
Perform the following ONLY after the fresh water tank is full.
Using the Water System
If your boat will be left unattended for at least a few days, switch the Pressure
Water Pump circuit breaker OFF. If this breaker is left on, pressure in the fresh
water system may fall and cause the water pressure pump to engage. If this
happens frequently, it could discharge your batteries.
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1. Verify power to the circuit breakers on the DC Control Panel - Helm
2. Switch the Auto Sump circuit breaker ON DC Control - Engine room.
3. Open the hot and cold shut-off valves on hot water tank and close
bypass valve. (See photo next page)
4. Partially open all cold water faucets, including the faucets for the
transom hand shower and bow and transom fresh water washdowns
(for locations - refer to photos on following pages.)
5. Supply AC power to your boat. Refer to Section 3 - Shore Power or
Generator Power to do this.
6. On the DC Control Panel - Helm, switch the Pressure Water Pump
circuit breaker ON. This activates the boat's pressure water pump,
which pressurizes the water system.
7. The fresh water system is primed when all air is purged from the
system's pipes and hoses. Starting from the aft of the boat, monitor
each sink tap and shower head. When a steady stream of water flows
from the tap or shower head, close the cold water faucet for that tap or
shower head, then open its hot water faucet (the washdowns supply
only cold water). When a steady stream of water again flows from the
tap or shower head, close the hot water faucet for that tap or shower
head. When you have done this for each sink tap and shower head, the
water system is primed.
8. Add water to the fresh water tank to replace that which was used in the
previous step.
When water pressure within the system increases to a predetermined
point, the pressure water pump automatically shuts off.
After filling, pressurizing and priming the fresh water system, simply open a
faucet to receive fresh water. As you draw water from the system, the
pressure in the system decreases. When the pressure decreases to a
predetermined point, the pressure water pump automatically turns on and
increases the pressure. This ensures a steady flow of water any time you
open a faucet.
Occasionally a recently filled system or one that has not been used for
some time may need re-priming. This is normal and is caused by an
accumulation of air bubbles at the pressure water pump. To re-prime the
fresh water system, repeat the steps Pressurizing and Priming the Water
System.
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3837 •U3 10/07
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