Lennox Hearth Direct Vent MPD-40 Series - Manual (Page 31)

31
NOTE: DIAGRAMS & ILLUSTRATIONS NOT TO SCALE.
Pilot for Honeywell Millivolt Gas Valve
(Loosening of Hex Fitting For Orifice Strip Tab Positioning)
Pilot for Honeywell Millivolt Gas Valve
Figure 64
Pilot for Honeywell Millivolt Gas Valve
Orifice Strip Tab Positioning
Figure 62
Figure 63
Hood Alignment Hood
7/16 in. Open End Wrench
Orifice Strip Tab
Take Care Not to Contact the Orifice Strip Tab
with the Hex Fitting Wrench - Distortion of the Tab
May Render the Pilot Inoperative.
Natural Gas Position -
NAT shown on tab
LP/Propane Gas Position -
1/16 in. Hole, LP and
Red Color shown on tab
NAT
P
L
Orifice Strip Tab Position Identification
For LP/Propane and Natural Gas
Top View of Hex Fitting and Orifice Strip Tab
Orifice Strip Tab
Pilot Hood Position After
Loosening Hex Fitting 1/4 Turn
Push Tab to Set
Gas Type Usage
Note - Orifice Strip Tab May
Be Randomly Located On Any
Side Of The Hex Fitting
b. Attach manometer to the manifold side
pressure test fitting and verify manifold pres-
sure reads 3.5 inches water column (0.87 kPa)
for natural gas, and 10.0 inches water column
(2.49 kPa) for propane gas.
c. Convert the pilot orifice as follows (see
Figures 62, 63 and 64 ):
Note - Use extra care not to engage the orifice
strip with the 7/16" open end wrench (contact-
ing the orifice strip could cause strip distortion
rendering the pilot inoperative). Also avoid
wrench contact to any of the other pilot parts.
Use a 7/16" open end wrench and turn the pilot
hex fitting counter-clockwise 1/4 turn. (See
Figure 62).
Note - The orifice strip tab may be randomly
located on any side of the hex fitting.
d. Push the orifice strip tab all the way against
the hex fitting to align the appropriate gas type
orifice
(see Figures 63 and 64). The type of
gas for which the pilot is set, is, the gas type
shown on the tab.
e. Retighten, clockwise, the pilot hex fitting
until the pilot hood aligns with the thermo-
couple and thermopile as indicated by the
arrows shown in
Figure 62.