Trouble Shooting; Pilot Does Not Light - 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 dealer or Controlled Energy for instructions.

TROUBLE SHOOTING

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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.
10
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 9.
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 ( ) and depress
this 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.