Trouble Shooting - Bosch 38B LP Installation And Operating Instructions Manual

Fig. 8 - Pilot burner with air screen/ pilot orifice
Main Burner Flames: The main burner flames should be
blue, with a more intense blue cone in the center core. Yellow
flames could be a sign of wrong size gas orifices or dirty
burners, or a blockage on the heat exchangers fins. If some
burners have yellow flames while others have good flames,
it is likely that dust, lint or spider webs have partially clogged
the burner venturis. To clean the burners contact a gas service
person.
Mineral Scale Build-up: The AquaStars heater, when
operated at lower temperature settings, do not accumulate
mineral build-up. If however, the heater is used at the higher
temperature settings and the water has a high mineral
content, periodic descaling may be necessary. The heating
coils should be flushed with a descaling solution. Consult
your service person.

TROUBLE SHOOTING

back)
Introduction
The AquaStar 38 burners are ignited by a water flow valve.
Numerous water related problems can cause this water valve
to malfunction such as: Insufficient water flow volume to
activate the burners at its minimum flow requirement; Dirt
in the water flow valve causing it to malfunction; Sediment
build-up in faucet aerators, or shower heads; Uneven
pressures between cold and hot. (with single lever faucets)
Plumbing cross overs. These water flow related problems
can cause the heater to deliver less than its full output, or
to fail to ignite or to shut down completely.
Problems are stated in upper case, bold face. Most common
causes for the problems follow in order of likelihood. The
suggested solutions require that the cover be taken off. To
this, remove incandescent particle tray, pull off the
temperature adjustment knob and unscrew and remove the
plastic collar and unscrew the central screw located at the
bottom of the front cover. Pull main cover out toward you
and lift up and out.
6 720 606 446
AIR SCREEN
PILOT ORIFICE
(see maintenance table on
PILOT DOES NOT LIGHT
1. No gas to the Aquastar
A. Gas cock on gas line may not be open.
B. Gas valve button has not been moved to "PILOT
POSITION". Slide button to right to single flame position
( ).
2. In-line Aquastar gas regulator jammed (usually on LP
gas)
Replace or unlock the regulator. Note: The regulator
furnished with the heater is designed for low gas pressure.
Excessive pressure will lock it up (propane only). Locking
usually happens if the gas pressure between the gas tank
(propane) and the water heater's gas regulator has not been
reduced. See page 2 for recommended correct gas pressure
and check with gas service person.
To unlock a regulator, consult your gas supplier.
3. Pilot orifice clogged and/or air screen 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.
See page 12.
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. Slide the gas
valve button ( ) to pilot position (
button until all the air has escaped, and the gas has arrived.
During this process, press on the piezo ignition
button separately until the pilot flame has ignited.
) and depress this
13