Dometic WH - 6GA Manuel D'installation Et D'utilisation page 18

Maintenance And Care
After draining the tank, because of the placement
of the drain plug, approximately two quarts of water
will remain in the tank. This water contains most of
the harmful corrosive particles. To remove these
harmful corrosive particles, flush the tank with either
air or water. Whether using air or water pressure, it
may be applied through the inlet or outlet on the
rear of the tank or the P/T relief valve. (If using the P/T
relief valve, the handle must be pulled straight out).
The pressure will force out the remaining water and
the corrosive particles.
If you use water pressure, pump fresh water into
the tank with the assistance of the on-board pump
or use external water for 90 seconds to allow the
fresh water to agitate the stagnant water on the
bottom of the tank and force deposits through the
drain opening. Continue adding water and draining
until the particles have been cleared from the water
remaining in the tank.
If sporadic water flow is encountered, open the P/T
relief valve to allow air into the tank. Using a small
gauge wire or coat hanger, poke through the drain
opening to eliminate any obstructions.
3. Replace the drain plug and close the P/T relief valve.
I The two quarts of water remaining in the tank after
draining the tank will not cause damage to the tank
should freezing occur.
6.4.2 Re-establishing the Thermal
Expansion Air Pocket

CAUTION: SCALDING HAZARD.
Turn off the water heater before opening the P/T
relief valve to establish air space. Storage water
must be cool. Failure to obey this caution could
result in minor or moderate injury.
1. Let the water cool or let the water run until it is cool.
2. Turn off the main water supply (the pump or water
hook up source).
3. Open the hot water faucet closest to the Water
Heater.
4. Pull the handle of the P/T relief valve straight out and
allow water to flow until it stops.
5. Allow the P/T relief valve to snap shut.
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6. Close the faucet.
7. Turn on the water supply.
8. Turn on the Water Heater and test.
At least once a year manually operate the P/T relief
I
valve.
9. When the P/T relief valve discharges again, repeat
Steps 1–8.
To flush with the P/T relief valve:
1. Lift the P/T relief valve handle.
2. Apply air pressure through the P/T relief valve.
For a permanent solution, Dometic recommends one of
the following procedures:
1. Install a pressure relief valve into the cold water inlet
line to the Water Heater. Set to relieve at 100–125 PSI
(689.47 kPa–861.84 kPa). Refer to "Replacement P/T
Relief Valve Parts" on page 20.
2. Attach a drain line from the valve to outside of the RV.
When attaching a drain line be sure the water flow is
not restricted.
3. Alternatively you can install a diaphragm-type
expansion tank in the cold water inlet line. The
tank should be sized to allow for expansion of
approximately 15 oz. of water and pre-charged to a
pressure equal to the water supply pressure. These
devices can be obtained from a plumbing contractor
or service center.
6.4.3 Flushing the Tank
Use this procedure for general flushing of the water
heater tank.
1. Turn off the main water supply (the pump or water
hook up source).
2. Remove the drain plug to drain the water from the
tank.
I If the water drains sporadically or trickles out of
the drain hole, open the P/T relief valve then use
a small gauge wire or coat hanger to remove any
obstructions from the drain hole.
L .P . Gas Water Heater
EN