State GPH-90N User Manual

Page 46

46 www.statewaterheaters.com

• Disconnect the hoses joining the tank and the heat

engine (upper hose is water outlet and lower hose is
water inlet).

• Connect addition length of hose (not provided) to

existing hoses. (Note: The heat engine hose is a
3/4” NPT thread which is different for a garden hose
thread.)

5 gallon pail of virgin,
food grade, white
vinegar (or virgin,
food grade,
citric acid).

Hot Water

Line

Cold Water

Line

Heat

Engine

FIGURE 40

• Connect a pump to the hose running to the heat

engine water inlet (lower fi tting). We recommend a
submersible utility pump for the circulating pump. (Note:
If a submersible pump is not used, connect a hose from
the circulating pump to the cleaning solution.)

• Pour approximately 4 gallons (15 litres) of virgin, food

grade, white vinegar or citric acid into a 5 gallon or
greater pail.

• Place the “intake” and “output” hoses into the pail of

cleaning solution. If a submersible utility pump is used,
place the pump into the pail of cleaning solution.

• Plug in the circulating pump.
• Connect the electrical power to the water heater and

run the heat engine.

• Operate the heat engine to circulate the cleaning

solution through the system for at least 45 minutes.
(Note: Lower the temperature below 104°F (40°C) or to
vacation mode.) Warning: Water will become hot very
quickly.

• Disconnect electrical power to the water heater.
• Remove the pail of cleaning solution and replace it with

a pail of clean water.

• Rinse the cleaning solution from the water heater as

follows:

• Connect the electrical power to the water heater and

run the heat engine.

• Allow the clean water to fl ow through the heat engine

for 5 minutes.

• Disconnect electrical power to the water heater and

circulating pump.

• Disconnect the hoses from the heat engine.
• Disconnect hoses and circulating pump, draining the

cleaning solution into the pail.

• Reconnect the original hoses to the tank.
• Remove the in-line fi lter at the cold water inlet and

clean out any residue. Assemble the fi lter back into the
unit.

• Open the shutoff valves on both the hot water and cold

water lines.

• Fill the tank with water.
• Connect the electrical power to the water heater.
• Restart water heater following lighting instructions.

DRAINING THE TANK

The water heater should be drained if being shut down
during freezing temperatures. Also periodic draining and
cleaning of sediment from the tank may be necessary.

Set the power switch to the “OFF” position.
OPEN a nearby hot water faucet and let the water run
until it is no longer hot.
CLOSE the cold water inlet valve to the water
heater.
Connect a hose to the drain valve and terminate to
an adequate drain.
OPEN the water heater drain valve to allow for tank
draining. NOTE: If the water heater is going to be
shut down and drained for an extended period,
the drain valve should be left open with hose
connected allowing water to terminate to an
adequate drain.
CLOSE the drain valve.
Follow instructions in the “Filling The Water Heater”
section.
Follow the lighting instructions on the label or see
“Lighting Instructions” in this manual to restart the
water heater.

FAULT INDICATION AND ERROR CODES
A red fault LED (lighting a large red exclamation point)
should be present on the display panel if a fault condition
exists.

A history of the last 9 error codes along with the current
error code is stored in memory and can be accessed via
the maintenance mode. If the current error code is zero,
“E00” shall be displayed (see Table 4).

1.
2.

6.
7.