Ignitor Sparks, But Pilot Will Not Light - Desa CERAMIC PLAQUE Service Manual

V E N T - F R E E
Problem

Ignitor sparks, but pilot will not light

Possible Causes
1. Gas supply is turned off and/or manual
shut-off valve is closed
2. Air in pilot line
3. Dirty pilot assembly
4. Insufficient gas supply pressure
Procedures
1. Check to be sure that the gas supply to the
heater is turned on. Be sure the manual
shut-off valve is open.
2. Be sure that the pilot line has been purged
for sufficient time to remove air from the
line.
The pilot line can be purged by turning the
control knob to the "PILOT" position and
fully depressing the knob. Ignition should
be attempted every 30 seconds until a
correct pilot flame is established. See
Owner's Manual for correct ignition proce-
dure.
G A S H E A T E R
3. Check the pilot assembly for dirt, cobwebs
4. Check gas supply pressure at the pres-
Problem
PILOT GRH/P 007A
Figure 14. Ignitor/Pilot Assembly
S E R V I C E M A N U A L
or other restrictions. Be sure the heater
has been turned off. First remove the wire
clip from the bi-metal strip located on the
pilot tube (see Figure 14). Remove the
brass cover and clean any dust or cob-
webs from the air/gas mixing chamber.
Reassemble the brass cover with the wire
clip and retest to see if a correct pilot flame
is established. If the above procedure
does not give satisfactory results, discon-
nect the pilot assembly and remove it from
the heater. Blow out the pilot tube from
both directions to remove any restrictions.
Also inspect the pilot line tubing for dirt,
kinks in the line or other restrictions. Re-
place the pilot assembly if necessary.
sure tap on the manual shut-off valve
below the heater and at the manifold pres-
sure tap next to the control valve (see
Figure 21, page 17) to be sure that enough
pressure is available to the system ac-
cording to the "SPECIFICATIONS" sec-
tion on page 13. If the inlet pressure is
correct and the manifold pressure is low,
replace the regulator, control valve or inlet
tubing as required.
Bi-metal Strip
Wire Clip
Brass Cover
15