70
PHTM II
Combi Installation, Operating & Service Instructions
110331-07 - 8/23
Figure 18-1: Ignitor/Flame Sensor Location
18
Service and Maintenance
(continued)
3.
Inspect heat exchanger combustion chamber.
Vacuum any debris found on coil surfaces. If
further cleaning is necessary, use heat exchanger
cleaning kit (111705-01). Water and vinegar are
acceptable cleaning agents. Do not use any other
cleaning agents, solvents, acid, or alkali products
of any kind to clean heat exchanger.
4.
Inspect target wall and burner door insulation.
If either shows signs of damage, it must be
replaced.
5.
Inspect burner door seal.
Look for signs of embrittlement or deterioration.
Replace if needed.
6.
Inspect burner.
Look for heat damage or other deterioration. Use
a nonmetallic brush or source of compressed
air to clean off dust or debris from ports. Ensure
burner is secured tightly to burner door.
Figure 18-2: Ignitor/Flame Sensor Spark Gap
.16" (4mm) - .19" (5mm) Gap
7.
Inspect ignitor/flame sensor.
A. Clean off any deposits found with steel wool.
Do not use sand paper or Emory cloth for this
cleaning.
B. Inspect ceramic portion for cracks and
replace ignitor/flame sensor if any are found.
C. Verify ignitor/flame sensor spark gap is within
range shown in Figure 18-2.
D. Verify gap between ignitor/flame sensor and
burner is within range shown in Figure 18-3
and Table 18-4.
Figure 18-3: Ignitor/Flame Sensor to Burner Gap
8.
Inspect blower gas valve assembly.
A. Look for dust, lint, or other debris that may
have been drawn into this assembly.
Excessive deposits may be vacuumed out.
B. Inspect all rubber and plastic components
on blower/gas valve assembly, looking for
deterioration. Replace blower and/or gas
valve if deterioration is found.
.16 in. (4 mm) - .19 in. (5 mm) Gap
Burner Door Mounting
Nuts (4X)
Ignitor/Flame
Sensor
Table 18-4: Electrode Gap
Boiler Size
Gap A
136 combi
.32 in. (8 mm) - .52 in. (13 mm)
136 combi (B)/
200 combi
.36 in. (9 mm) - .56 in. (14 mm)
200 combi
(LP above 2,000 ft. (610 m)) .59
in (15 mm) - .79 in. (20 mm)
Gap "A"
