Bosch Appliances GWH 425 EF Water Heater User Manual


 
156 720 607 017
OPERATING INSTRUCTIONS
Before operating the heater, make sure that the system is
filled with water.
Open the cold water inlet supply to the heater fully.
Open a hot water faucet to permit the water to fill the heater
and the piping and to eliminate the air trapped in the system
Close the hot water faucet after the water flows freely and
all the air has escaped from the system. The water heater is
now ready to operate.
FOR YOUR SAFETY READ BEFORE
OPERATING YOUR HOT WATER HEATER
Warning: If you do not follow these instructions
exactly, a fire or explosion may result causing property
damage, personal injury or loss of life.
A. This appliance is equipped with electronic ignition for
lighting the pilot and main burners. When turning the heater
on, follow these instructions exactly.
B. Before operating the unit, set the On/Off switch to the
On ( ) position. The On/Off switch is located behind the
flip-down coverplate on the front panel strip. Smell all around
the appliance area for gas. Be sure to smell next to the floor
because some gas is heavier than air and will settle on the
floor.
WHAT TO DO IF YOU SMELL GAS
- Do not try to light any appliance.
- Do not touch any electric switch; do not use any phone
in your building.
- Immediately call your gas supplier from a neighbor’s
phone. Follow the gas supplier’s instructions.
- If you cannot reach your gas supplier, call the fire
department.
C. Use only your hand to push in the on/off control button.
Never use tools. Follow these instructions exactly. If control
button is jammed, close the gas supply and call a qualified
service technician. Attempted forceful repair may result in a
fire or explosion.
D. Do not use this appliance if any part has been under
water. Immediately call a qualified service technician to
inspect the appliance and to replace any part of the control
system and any gas control which has been under water.
LIGHTING AND OPERATING INSTRUCTIONS
1. STOP! Read the safety information on the front panel of
the heater.
2. The gas valve must be turned off by putting the On/Off
switch to position “ ” (see fig. 10). Wait five (5) minutes
to clear out any gas. If you smell gas, STOP! Follow “B”
in the safety information above. If you don’t smell gas, go
to next step.
3. This water heater is equipped with a safety pilot burner
and an automatic ignition control system.
4. Set the ON/OFF switch (flip down cover plate on front
panel strip) marked / to the “ ” position. In this
position the water heater is ready to use.
5. Verify that the power supply to the appliance is turned
on.
To operate the heater, set the ON/OFF switch to position “ ”.
The switch is located behind the flip down cover plate on the
front panel strip.
To shut down the gas to the heater, set the ON/OFF switch to
position “
G661_004
Temperature Adjustment Knob
Decrease temperature
and increase flow
Increases temperature
and decreases flow
Fig. 10 - Principles of Operation
The 425 EF LP and 425 EF NG water heaters have a gas
control that modulates burner input in response to flow. Its
purpose is to ensure that the hot water temperature will
remain steady, although the demand for water flow might
vary (down to 1/2 gal/minute). To adjust the temperature on
your 425 EF, turn on a hot water faucet to its maximum
flow. At the 425 EF, turn the large knob located beneath
the main gas controls on the front of the heater all the way
to the right (clockwise). See Fig 11. This will produce a
temperature rise of approximately 90°F at flow rates between
.5 and 2.0 gallons per minute. Given that average incoming
water temperatures are 50°F, this heater will produce
approximately 140°F water at these flow rates. Turning the
dial all the way to the left (counterclockwise) will produce a
temperature rise of approximately 45°F for flow rates between
1.0 and 4.0 gallons per minute. This will result in a higher
flow rate, but at cooler temperatures. Turning the dial to
locations in between will give various temperatures between
6. Turn the hot water faucet on to the minimum flow required
to activate the heater. The automatic ignition system first
ignites the safety pilot burner which then ignites the main
burner in about 4 seconds. The power exhaust will then
activate.
7. The pilot flame will extinguish 10-30 seconds after the
burners come on. The burners will remain on until the hot
water tap is turned off.
NOTE: On a first time installation, existence of air in the gas
supply line and in the water line may cause some ignition
delay. In that case, repeatedly open and close the hot water
tap in order to restart the ignition process until all the air
has been purged.
TO TURN OFF GAS TO APPLIANCE
Turn off the manual lever on the gas supply line to the heater
and set the ON/OFF switch to the OFF ( ) position, see
Fig. 10.
SETTING THE WATER TEMPERATURE