5
MANIFOLD
PIPE PLUG
C99019
Fig. 5 -- Two--Stage Burner Assembly
REGULATOR COVER SCREW
PLASTIC ADJUST SCREW
LOW STAGE
GAS PRESSURE
REGULATOR ADJUSTMENT
MANIFOLD
PRESSURE TAP
INLET
PRESSURE TAP
ON/OFF SWITCH
REGULATOR SPRING
(Propane - White,
Natural - Silver)
HIGH STAGE GAS
PRESSURE REGULATOR
ADJUSTMENT
A07804
Fig. 6 -- Two--Stage Gas Valve
22. Install plastic adjust screw into the low stage gas regulator.
turn clockwise 9.5 turns (see Fig. 6).
23. Verify igniter, flame sensor, orifice/main burner
relationship prior to completing conversion. (See Fig. 4.)
Partially slide burner rack assembly into unit.
24. Disconnect the orange wire from the combustion air
pressure switch and connect it to the orange wire on the low
gas pressure switch (LGPS) equipped with a 1/4 in. male
quick--connect
terminal. The low gas pressure switch
should have one unconnected orange wire remaining.
Connect this wire to the vacant terminal on the combustion
air pressure switch (see Fig. 8).
25. Reconnect the violet wires removed in item 5 to the rollout
switch and reinstall the rollout switch.
26. Reconnect orange sparker cable to sparker and reconnect
the white flame sensor wire to the flame sensor.
27. Reconnect the remaining wires removed in item 5 to the gas
valve. Connect the gray wires to (HI). Connect the blue
wires to (M). Connect the brown and green/yellow wires to
(C).
28. Slide burner rack assembly into base pan. Align burner rack
with screws on sheet metal partition and slide assembly
back tight to the partition. Replace the screw attaching the
burner rack to the base pan removed in step 4. If the Fan
partition mounting bracket was removed, slide bracket back
into placed and fasten with 2 screws. (See Fig. 2.)
29. Reconnect the brown wire from the burner assembly to the
fan partition panel, using the ground screw saved from Step
8.
30. Remove the 1/8 in. pipe plug on the gas manifold and
connect a pressure manometer (see Fig. 5).
31. Reconnect electrical power and gas supply to the unit. For
propane applications, the gas pressure must not be less than
11.0 IN. W.C. or greater than 13 IN. W.C. at the unit
connection. A 1/8--in. NPT plugged tapping, accessible for
test gauge connection, must be installed immediately
upstream of the gas supply connection to the gas valve and
downstream of manual equipment shutoff valve.
The newly installed low gas pressure switch is a safety device used
to guard against adverse burner operating characteristics that can
result from low gas supply pressure. Switch opens at not less than
6.5 IN. W.C. and closes at not greater than 10.2 IN. W.C.
This switch also prevents operation when the propane tank level is
low which can result in gas with a high concentration of impurities,
additives, and residues that have settled to the bottom of the tank.
Operation under these conditions can cause harm to the heat
exchanger system.
This normally open switch closes when gas is supplied to gas valve
under normal operating pressure. The closed switch completes
control circuit. Should an interruption or reduction in gas supply
occur, the gas pressure at switch drops below low gas pressure
switch setting, and switch opens. Any interruption in control
circuit (in which low gas pressure switch is wired) quickly closes
gas valve and stops gas flow to burners.
FIRE AND EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury and/or property damage.
Never test for gas leaks with an open flame. Use a
commercially available soap solution made specifically for
the detection of leaks to check all connections.
!
WARNING
IMPORTANT
: Restart unit and leak check all gas connections
including the main service connection, gas valve, gas spuds, and
manifold pipe plug. All leaks must be repaired before firing unit.
32. Fire unit and verify proper ignition and proper sequence of
operation (Table 2). See Table 4 for proper low stage and
high stage manifold pressure settings for your unit. Adjust
the gas valve setting for high and low stages by turning the
plastic adjustment screws clockwise to increase pressure and
counter--clockwise to decrease pressure for the respective
stages. Refer to Table 3 for required rated heating input
rates. Replace regulator cover screws when finished (see
Fig. 6).
33. With control access panel removed, observe unit heating
operation in both low stage operation and high stage opera-
tion. Watch burner flames to see if they are blue in appear-
ance, and that the flames are approximately the same for
each burner (see Fig. 9).
34. Turn off unit, remove pressure manometer and replace the
1/8 in. pipe fitting on the gas manifold (see Fig. 5).
35. Attach warning label (P/N 48DU500076) to visible side of
gas valve.
36. Attach conversion label (P/N 48VL500206) above unit
rating plate on exterior of unit.
37. Attach completed conversion responsibility label (see Fig.
10, P/N 48VL500207) inside control access panel.
CPL
P
CONV
