1.4.3 Pilot Flame Adjustment
The pilot flame should be adjusted to produce the proper millivolt output from the pilot sensing device.
Millivolt output for the thermopile should be between 300 and 500 millivolts. Figure 1-3 shows the pilot
assembly with examples of the incorrect and correct pilot size. Example A illustrates a pilot flame size that
is too small to produce sufficient millivolt output. Example B is the correct size for proper millivolt output.
B
Figure 1 -2 Pilot Assembly, Flame Adjustment
This test requires a DC millivolt meter set to a scale of 0-1000mv.
Locate the thermopile wires coming from the thermostat/High Limit box
going to the gas shut off valve. The wire insulation size decreases near the
gas valve connections.
Connect the negative (-) test probe to pilot bracket.
Connect the positive (+) test probe to one of the High Limit terminal
connections
PRESSURE REGULATOR LOCATION
(UNDER CAP SCREW)
PILOT ADJUSTER LOCATION (UNDER CAP SCREW)
Figure 1-3 Gas Valve Showing Location of the Pressure Regulator and Pilot Adjusters
1-10
a.
b.
c.
d
.