Bosch Appliances 125B NGL Water Heater User Manual


 
11
C. Gas regulator may be shut or damaged.
2. In-line AquaStar gas regulator jammed (usually on
LP gas)
Replace or unjam the regulator. Note: The regulator
furnished with the heater is designed for low gas pressure.
Excessive pressure will lock it up (propane only).
Jamming usually happens if the gas pressure between the
gas tank (propane) and the water heaters gas regulator
has not been reduced. See page 2 for recommended correct
gas pressure.
3. Pilot orifice clogged and/or air screen dirty, or pilot
gas filter is dirty.
Clogging of the pilot burner can be caused by dust and any
suspended matter contained in the ambient air. Although
the filters can lengthen the cleaning intervals, they can never
completely prevent such clogging. In consequence the gas
jet issuing from the pilot orifice is reduced and or the air
mixture is reduced. The pilot flame is weak and thus can
no longer heat the thermocouple sufficiently. For cleaning
purposes, the air filter screen is pulled off, washed and
blown out. The pilot orifice has likewise to be cleaned or
exchanged. To clean the pilot consult a gas service person
.
4. Air in the Gas Line
Note: Normally this is a problem only at the time of initial
installation, after the pipes have been worked on, or after a
propane tank has been allowed to empty, or after the heater
has been shut down for a long time.
Bleed all the air trapped in the gas line. Because of the
very small pilot orifice (especially on LP gas models),
bleeding out all the air could take several minutes. Depress
the pilot button ( ) until all the air has escaped, and the
gas has arrived. During this process, press repeatedely on
the piezo ignition button until the pilot flame has ignited.
PILOT LIGHTS BUT FLAME GOES OUT WHEN BUTTON
IS RELEASED
1. Pilot push button was not pushed in far enough or
was not held in long enough
Once pilot flame has been lighted. Hold button pushed in
for at least 15 seconds to give time for the pilot flame to
properly heat the tip of the thermocouple.
2. Pilot flame improperly aimed or is too weak so it
is not properly heating the tip of the thermocouple.
The Pilot flame should be a sharp blue flame and aimed at
the tip of the thermocouple so that it envelops 10 mm (3/8
) of the thermocouple tip. Pilot flame has to be properly
aimed at the thermocouple. See Fig 8.
3. Poor thermocouple connection at the
electromagnet
Note: Electromagnet is part #8707201094 located on the
right side of the gas valve behind the piezo pushbutton
assembly. Check the tightness of the thermocouple
connection nut at the electromagnet: The Electro-magnet
connection is a large aluminum 17mm hex head nut. The
thermocouple end is a 5 mm brass nut which screws into
the 17 mm nut.
Tighten the thermocouple nut snugly but not too tight.
4. Poor circuit connections at the ECO. (Energy Cut-
Off overheat protection)
Oxidation or looseness of the ECO terminal connections
can result in millivolt current loss through the thermocouple
safety circuit. Clean terminals with very fine sand paper or
an eraser and reconnect ECO leads.
5. Faulty ECO (part #8707206017)
If cleaning the terminals attached to the ECO did not fix
the problem, connect a jumper wire between the two wires
and try to relight the pilot. If the pilot flame now remains
on, replace the ECO. If the flame still goes out when the
button is released, the ECO is not defective. Go to next
step.
6. Faulty thermocouple (part #8747202083) or
electromagnet) Unless these 2 parts are at least 8
to 10 years old, it is very unlikely that they are
faulty. Before testing, reconfirm that #2 is absolutely
correct, and that all connections are clean and
tight.
Consult a gas service person to test and change the
thermocouple.
BURNERS DO NOT IGNITE WHEN HOT WATER IS
TURNED ON OR WHEN A CIRCULATOR PUMP IS
OPERATING
1. Pilot is not on.
Light the pilot. See lighting instructions.
2. Gas valve button not positioned on Burner Position
Be sure once the pilot flame is on, that after a 15 to 20
second wait, the main burner button ( ) is pushed all
the way in.
3. Water flow rate at hot water tap is too low.
Note: The AquaStar models 125BL require 1.8 gallon per
minute flow to activate the burners. This is a flow which
would fill a quart jar in 8 seconds.
4 . Cold water inlet filter on heater is dirty.
Remove filter and clean. This screen filter is located at the
inlet side of the brass water valve (fig 11, #32). Check and
clean faucet aerators too.
5. Inadequate pump used on a recirculating loop
If unit is plumbed in a recirculating loop system verify that
the primary circulator pump is sized properly. GF 26-96,
Taco 009 or equivalent is required. See diagram on page 4.
6. Crossover in household plumbing
The AquaStar burner activates when there is sufficient water
pressure drop in the AquaStar water valve assembly ie.
when a hot water faucet is opened. If there is a crossover in
the plumbing, the necessary pressure drop in the AquaStar
will be insufficient, or totally eliminated. A plumbing
crossover can be caused by a bad washer at a single lever
faucet or incorrect plumbing or a mixing valve in the line,
etc. which permits hot and cold water to mix in the
plumbing. The crossover will create a back pressure in the